'90 "T-Type" Turbo 3.4 Five-Speed, 2nd Build

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Rettax3
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'90 "T-Type" Turbo 3.4 Five-Speed, 2nd Build

Post by Rettax3 »

1990 Chevrolet Beretta ‘T-Type Turbo 3.4 V-6 Build #2

The Car:
This was my first Beretta. I bought this several years ago from my ex-girlfriend after she had it for a number of years. I had replaced the serpentine belt, alternator, heater-core, clutch, transmission oil-seals, rebuilt the power-steering pump, and replaced one wheel and rear wheel bearing (I bent one of the rears against a curb after avoiding a truck that swerved into my lane), rebuilt the ignition-lock to better-than-factory, and put in new front brakes while she had this car. I also installed a Pioneer CD deck for her. When her health deteriorated enough that she didn’t want to drive a clutch anymore, I offered to buy the car, and she sold it to me for $750.
Car.png
It is an original 3.1 V-6 5-speed blue-on-blue car, F40 ‘Heavy Duty’ suspension. It now has roughly 157k miles on it.

I had installed a Firebird wing-spoiler, 15” Beretta GT Cross-lace rims, and grafted in a Turbo 280Z hood-scoop to feed the intercooler after I located it to where the battery originally sat, and moved the battery to behind the engine on a modified HAVC (blower) plenum. ICM was relocated to the recess behind the right strut-tower with a new ground-wire to get it away from the heat of the exhaust manifold, and I installed Accel 8mm cut-to-fit ignition wires, mostly because they were cheap and in-stock at the parts store and because I had had good experiences with them on my old Camaro. I had also put blue LED lighting into the instruments, driving-lights behind the grill, and eventually removed the diffuser lenses from the headlights replacing them with clear plexi-glass, which made for some obnoxious spot-lights up front (these headlights are currently on the ’95 Z-26 I had, as it is ~ 1” shallower and allowed for grills to be placed in front of the headlights, which fit the look I was going for with that car). I also installed an in-flight adjustable boost-controller, and ran the car anywhere from 4-5 psi (normal setting –enough to b!tc#-slap your average 4.6 GT Mustang) to 9psi (high setting –better for highway grudge-matches) and even a run at 12psi (unintentional, but the engine handled it okay). I adapted a spare heater-core to help provide cooler coolant to the turbo too, which was eventually a source of dispute from a previous bstuff member who thought I was trying to pass that off as an intercooler. :roll:

The Reason:
Well, it may sound a little ridiculous, but with the LG5 turbo 3.1 in the car, it was fast, virtually uncontrollable at full-throttle in either first or second gear due to excessive torque-steer, and it ran great for me for years. But, a friend of mine had bought my ’92 Grand Am SOHC Quad from me, and was planning on shoe-horning a semi-built 3800 Series II Super-Charged engine into it (an engine that I built for him), and I didn’t think my turbo 3.1 would be competitive against it, so in an effort to keep in front of the Joneses, as it were, I started to build up a 3.4 for my car. As it turned out, my friend never completed his project, and gave it all back to me, so I bought a 1989 GTU to put the engine into instead, but that is a different story… :P

The Engine:
Engine.png
I ran across a wrecked ’99 Grand Am GT with low miles in the salvage-yard, but the 3400 was already gone from it. About a week later, the engine was returned, allegedly due to a blown head-gasket. I bought the engine, complete from intake to oil-pan, with all accessories, wiring harness, and PCM for $65, on the condition that it held no warranty, and the yard wouldn’t have to see it again. No problem! As it turned out, it only had the typical 3x00 LIMG failure, the head-gaskets were fine. But I didn’t want the heads that were on it, as I wanted to retain the LG5 “3.1 Intercooled Turbo” manifold that was already in my car, and more era-correct MPFI-style intake setup, even if that ultimately cost me a little bit of power. I started with a good set of MPFI heads, modified them to accept the 3400’s roller-based rockers, matched in correct-length push-rods, rebuilt all 12 roller-lifters, and ported-out the heads, fabricating locator-pins for the modified LIMG to keep it from walking when the lower intake manifold was set in place. I modified the cast aluminum oil-pan for an oil-return from the turbo, and I set up an oil-supply line from the oil gallery on the front of the block. I painted the exhaust-system and turbo’s hot-side with high-temp black paint, built a 2.25” short-run catless side-outlet exhaust system for the car, and put in a new clutch (this installation coincided with the failure of the first clutch I had put in the car before I owned it, and my ex had conveniently thrown out all of the warranty info –thanks- leaving me with the additional cost of a new clutch). I welded up a temporary front engine-mount out of 1/8” steel (which was already distorting slightly by the end of the week, but held the engine in place for testing, as intended), and put about fifteen miles on the engine during testing. Unfortunately, the engine developed only very low oil-pressure, and replacing the oil-pump didn’t help. So, out of time and patience for the project, I pulled the 3.4 and dropped the LG5 3.1 back in.
A couple of years ago, I finally got around to the 3.4 again, and found that the rear main crankshaft bearing was chewed and the crank was toast, certainly due to the LIMG failure it suffered before the donor car was wrecked and scrapped. Things like this make me wonder about the timing of certain wrecks, and the pay-out amount of full-coverage insurance that doesn’t pay to fix engines with defective engineering…
I needed a decent front engine mount for the 3x00 block since I was working with an older Beretta, and my old temporary one couldn’t properly support this engine with the old turbo, exhaust, and 3.1 ECU during very gentle test-driving. It wouldn’t hold up for long under the updates I made, so I didn’t bother with it, except to use it as a template for a heavier-duty unit. I used ¼” thick 3”x3” steel angle stock for this one, and it looked and worked perfect.
11-17-12_1351.jpg


1989 SuperCharged 3800 Srs-II (First)Six-Speed GTU
1990 Turbo 3.4 5-Speed T-Type
1990 4.0L 4-Cam 32-Valve V-8 5-Speed Indy GTi (Project)
1990 Stock(!) 3.1 MPFI Auto Indy
1995 LA1/L82 4T60E Z-26
1995 3.4 DOHC Turbo 5-Speed Z-26
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Rettax3
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Re: '90 "T-Type" Turbo 3.4 Five-Speed, 2nd Build

Post by Rettax3 »

The Exhaust:
4Exhaust.jpg
I decided to go all out on it, built a full set of 1.5” primary-tube block-hugging headers (I couldn’t find ANYONE who built and sold headers for a 60-degree V-6 turbo application) that I port-matched to the heads, installed a brand-new T-4 turbo, bolted in an adjustable Audi K-03 external waste-gate, and rebuilt the exhaust as 2.5”, all mandrel-bent tubing with a high-quality flex coupling and single Thrush ‘Welded’ muffler to replace my aging glass-packs. The resulting sound is perfect, lots of aggressive growl with a faint metallic ring, but no rasp and no bark –just bite! It isn’t a quiet car, but it isn’t really loud either.

The Transmission:
The car was an original Muncie/Getrag 282 5-speed, but the original tranny had issues due to low oil levels from a long-term leak, so I replaced it with a junk-yard salvage some time ago. Unfortunately, the salvaged transmission would not shift into third or fourth, and it is quite a jump from second to fifth, even with the LG5’s torque. Still, I had used this car to tow home my Z-26 when I first bought that car, so it is doable. :roll: But I had finally gotten a couple of replacements ready. I checked the gearing of my somewhat rare ’90 Grand Prix 3.1 5-speed Muncie (the mounts are different, and the housing is cast differently and incorporates a screw-on oil-cap, rather than the regular flip-handle dip-stick, and it was rumored that first and second gear were a little spunkier, which they aren’t), and finding it to be the same as the regular Munci/Getrag 282s in gearing, I just used a cleaner one I had salvaged from a late-eighties/early nineties Z-24 instead (oops!). I later realized my mistake, when I remembered that the Cavalier and Fiero, among others, used a Muncie with a gear-driven VSS (Vehicle Speed Sensor) that is incompatible with the hall-effect pulse-generator VSS used by the Berettas, so I had to improvise for the speedometer. I used a junk Fiero speedometer crudely grafted in to an extra Berretta gauge-cluster I had to get me by until I decided on what to do, and I am still working on a digital instruments set from another vehicle.
5Transmission.jpg
Top to Bottom: My ‘Retta’s original analog Cluster, Modified Z-24 Cluster, Factory Beretta Digital Cluster.

Early ‘90s S-15 Instruments currently in the car. The Z-24 Cluster would work much better and is ready now as a Drop-in, but it is fried, so until I find another donor…

The Wiring and Control Unit:
I considered using the car’s original ECU et al to run the 3.4, as I knew it could handle the turbo’s boost, in fact I had it dialed-up briefly to 12 psi and it ran fine, but I also knew that I would have to tune it to run the bigger engine and ported heads and manifolds just right, and that I would be risking maxing-out my fuel injectors. The wiring in the engine-bay was also suffering from age and mostly heat from the turbo, so I decided to go with the ’99 GA GT PCM I had for the engine. The fuel injectors are the same ones used on the Series II 3800 L36 normally-aspirated engines, so I was comfortable with the added load the boost would put on them. I started fresh with the wiring, unpinning every wire from the PCM and stripping the wiring-harness out completely, then I ran each necessary wire back from each sensor/solenoid/etc to the PCM, which was now to be placed where the old intercooler had previously resided, in the battery’s original spot. The biggest problem this caused was the need for the high-resolution CKP (24x Crank Position Sensor) behind the crankshaft pulley. This meant drilling and tapping into the timing case to precisely mount the 24x CKP, or replacing the timing case with one from a 3x00. I chose the latter option, and found that my lower radiator hose no longer fit onto it (the 3x00s use a lower radiator hose that maintains a constant diameter along its’ length, rather than having a larger diameter at the engine-side like the MPFI engines), and my power-steering pump needed 10mm spacers placed between it and the mounts on the timing case. Then, I had to re-bend my power steering line (I didn’t have a spare 3x00 PS pump to work with, and couldn’t make myself rob the one from my Z-26, which was running fine at that time). What a PITA!


1989 SuperCharged 3800 Srs-II (First)Six-Speed GTU
1990 Turbo 3.4 5-Speed T-Type
1990 4.0L 4-Cam 32-Valve V-8 5-Speed Indy GTi (Project)
1990 Stock(!) 3.1 MPFI Auto Indy
1995 LA1/L82 4T60E Z-26
1995 3.4 DOHC Turbo 5-Speed Z-26
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Rettax3
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Re: '90 "T-Type" Turbo 3.4 Five-Speed, 2nd Build

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The Intake (and Head Lights):

And Head Lights? I had a Blackstone intercooler sitting around and looking bored, so I decided to set it up in front of the car for giggles. I never did laugh though, and neither did the Blackstone. The Berettas have D-shaped cutouts on each side of the radiator core, which are almost perfect for 2” piping to fit through. Some of the tighter elbows I used on the intake piping were factory rubber or silicon, some were cast aluminum, and most of the intake piping and bypass valve return-air line was extruded aluminum. Almost all of it was ‘lying around’ from other projects I’d done in the past, or left-overs from parts I had salvaged. I had to buy one stainless-steel coupler for the intake, I picked it up new for ~$3. I used Saab turbo hose-clamps almost exclusively (I had a bucket of them to pick correct sizes from), so most of the intake can be disassembled with one size tool, instead of switching between ¼” and 5/16” all the time. I hate that. I mocked-up several routing options, and found that with the piping and elbows I had available, I could build a complete FMIC set up for this car, but the elbows would interfere with the headlights. So I made new headlights. I used a set of dual-filament square headlamps, fancier ones with the ‘city-light’ 194 bulbs off to the side, and the headlight buckets from a Fiero (I got a lot of Fiero parts in a trade I made). I also built a set of grills across them, like I did on my ’95 Z-26, but kept the egg-crate grill in the middle instead of fitting in a Z-34 Lumina grill, like I did on the Z-26). It still needs some work to look right, but it is okay for now, and I think the car looks very aggressive this way. But back to the intake… I also fit in an ebay-special bypass valve –I couldn’t use a BOV (Blow-Off Valve) because of the GA GT’s MAF (Mass Airflow Sensor), as it messes with the computer’s calculations to suddenly dump out a bunch of air the computer has already measured and calculated fuel for. I bought a blue cone-filter for the intake, and it sits over the battery-tray, in the same area fed by the hood-scoop, so if I box it in correctly, I should get some ram-air pressure in there, too.
6Intake, Lights.jpg


Despite the low-res picture quality, it can be seen why the Blackstone is such a good choice. The air-tubes are extruded aluminum with internal vanes formed into them. This yields a huge internal surface area, compared to plain hollow tubes units, and also makes the structure of the IC much stronger and more rigid.

Fiero Head Lights on a Beretta? And upside-down and swapped left-to-right, too. At least they don’t flip-up anymore… Or is that too bad they don’t?

This hood used to look really good a few years ago, but is desperate now for a bit of body-work and fresh paint.

That huge on-its’-side-distributor looking thing is the external waste-gate for the turbo. $60 would buy an ebay-quality unit in color-matching blue, this one was free with an Audi K-03 turbo I bought for ~$35, and will probably last forever, is fully adjustable and is rebuildable.

The Turbo:
7Turbo.jpg
As previously mentioned, it is a brand new Garrett Airresearch T-4, .60 A/R compressor (a little big, even for a semi-built 3.4) externally waste-gated and oil-cooled unit. It was a gift from a family member, who decided they wouldn’t use it and didn’t need it anymore. The externally waste-gated aspect was a serious pain to deal with considering that every part of the exhaust system was being fabricated bend by bend, and I almost hybrided the turbo with a T-3 I had, but external waste-gates supposedly offer better turbine-speed and boost-pressure control than internal waste-gates, so I left it alone.

The Plumbing:
To help the oil-cooled-only turbo live a little longer, I installed an oil-cooler between the A/C condenser and the intercooler, and I put a pre-screener inline before that, just to keep any debris out of the turbo and help prevent buildup from getting into the oil-cooler. I fabricated aluminum tubing with stainless-steel fittings where I could for vacuum, boost-pressure, and oil-supply, and used blue silicon tubing where the aluminum wasn’t convenient.

Details, Details…:
8Details.jpg
The original Beretta cooling-fan wasn’t going to fit in here anymore, not with upper-deck air-intake pipes routing around, so I used another fan from an import (I honestly have no idea what it came from, I’ve had it and the radiator it was bolted to sitting in one place or another for several years now), and it slid almost perfectly in place. I fabricated new, heavier-duty mounting brackets for my behind-the-grill lights (since the headlights’ header-panel no longer fit in the car, due to the huge FMIC), and put new lights on them, too. The old lights and header-panel will likely go into the GTU someday.

…I’ve had issues with this build, like the speedometer incompatibility, and oil-leaks from the turbo’s supply lines that just won’t dry-up (I probably won’t use aluminum tubing with compression-fittings again, I’ll stick with copper or go to flare-fittings). Additionally, the anti-theft component of the GA GT’s PCM has been a constant irritation, and the control module has now started to become unreliable. I have a new module to drop in, maybe this weekend, but I am thinking of going with a different PCM altogether if I can find one that doesn’t have the anti-theft system built in. Unfortunately, this car has done a lot more sitting lately than running, and that is a shame because it was a blast of a car to drive before, and has so much more potential now.


1989 SuperCharged 3800 Srs-II (First)Six-Speed GTU
1990 Turbo 3.4 5-Speed T-Type
1990 4.0L 4-Cam 32-Valve V-8 5-Speed Indy GTi (Project)
1990 Stock(!) 3.1 MPFI Auto Indy
1995 LA1/L82 4T60E Z-26
1995 3.4 DOHC Turbo 5-Speed Z-26
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Slinky
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Re: '90 "T-Type" Turbo 3.4 Five-Speed, 2nd Build

Post by Slinky »

That's a lot of reading what is your current engine set up/specs/HP/Quartermile ET?


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Rettax3
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Re: '90 "T-Type" Turbo 3.4 Five-Speed, 2nd Build

Post by Rettax3 »

Slinky wrote:That's a lot of reading what is your current engine set up/specs/HP/Quartermile ET?
:D It was a lot of writing, too! Do you remember thebuild thread on my 3800 GTU that I had on bstuff back then?

To abbreviate;
-'99 Grand Am GT 'E' Code 3400 block, rotating assembly, cam, roller lifters.
-9.94:1 Compression Ratio.
-3.1 MPFI heads, moderately ported intakes, more than moderately ported exhaust. Modified for 3400 roller rockers.
-LG5 intake manifold, moderately ported.
-Custom 1.5" Primary tube "balanced" headers.
-Garrett T-04 60-trim turbocharger, externally waste-gated.
-Very mild boost level, ~3PSI, until another couple of hundred miles on the car. Final goal for around 7PSI, maximum intended ever is 9PSI.
-Adjustable Audi K-03 external waste-gate.
-HUGE Blackstone FMIC.
-Ebay special bypass valve.
-3.5" warm-air intake, will get boxed-in for ram-air CAI.
-Custom 2.5" mandrel-bent short-run catless exhaust, side-outlet three-port custom resonator.
-3400 SFI fuel injectors, PCM operating engine only as a stand-alone.


No idea what the HP numbers are for sure. It already seems to pull as hard as my 3800 SC Series II, which is stock at 240 HP, and is NOT stock 8) , I'm estimating 275HP on that car. The old LG5 was rated at 205, I figure with a five-speed, better intake, and bigger low restriction short-run exhaust, 225 is a fair guess. Thusfar, I wouldn't say that I've exceeded the old LG5 I had in here, but once I get the boost dialed up a little more, it should push a fair amount more. As for torque, I would say it has at least as much as the LG5 did already. I'm hoping for around 275 HP on this car too, and higher torque numbers.

I haven't run any of my cars on a dyno, or at a track, so I don't know ETs either. I am nowhere near sophisticated enough for all of that. :wink: I drive my cars, not race them. I remember when you joined on bstuff, and seeing where your car is now is very impressive. I don't intend for this car to match up to that, but I won't have much expense put into mine either, so that is my trade-off.


1989 SuperCharged 3800 Srs-II (First)Six-Speed GTU
1990 Turbo 3.4 5-Speed T-Type
1990 4.0L 4-Cam 32-Valve V-8 5-Speed Indy GTi (Project)
1990 Stock(!) 3.1 MPFI Auto Indy
1995 LA1/L82 4T60E Z-26
1995 3.4 DOHC Turbo 5-Speed Z-26
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Slinky
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Re: '90 "T-Type" Turbo 3.4 Five-Speed, 2nd Build

Post by Slinky »

That's a very good set up, my car only pushes 6-7psi and makes around 260whp i believe, And how are you getting away with just using 3400 fuel injectors? Do you have an adjustable fuel pressure regulator? And I'm not knocking your build or anything but why did you use 3.1 L heads? With a 3500 or even 3400 top and you would gain a lot


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Rettax3
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Re: '90 "T-Type" Turbo 3.4 Five-Speed, 2nd Build

Post by Rettax3 »

Slinky wrote:That's a very good set up, my car only pushes 6-7psi and makes around 260whp i believe, And how are you getting away with just using 3400 fuel injectors? Do you have an adjustable fuel pressure regulator? And I'm not knocking your build or anything but why did you use 3.1 L heads? With a 3500 or even 3400 top and you would gain a lot
No problem at all, I'm glad you asked. The 3400 injectors are the same ones used on N/A 3800s up through at least the Series II L36s, so I know they have a lot more flow capability than 3.4 Litres of displacement normally need. GM does not push their injectors to 100% duty cycle even at WOT at red-line, so a reasonable boost shouldn't kill these too quickly. Because I am running a 3400 PCM with a MAF in front of the turbocharger, the injectors should be matching the air-charge about right, at least at lower boost ranges.

I know there are strong opinions on this, and getting a custom tune is the only way to have this reach its' 100% potential, but I compare my cars to what they were stock, not to what they could be, otherwise I simply wouldn't start off with a Beretta. :pardon: For now, stock tune will run the car fine -I am even leaving the low RPM limit in place for now (PCM thinking it is in neutral gear). This is just how I break-in my builds...

As for the reasoning to the 3.1 heads... SuperDave back on bstuff couldn't seem to stop laughing about it because his shop used those heads "for door-stops", but I wanted very much to retain the LG5 "Turbo Intercooled 3.1" manifold, which required retaining MPFI heads. As a secondary concern (or excuse, however you like it :pardon: ), the MPFI top-ends have a stronger low-end and mid-range torque band, which is nice with a lag-prone turbo setup. Unfortunately, the exhaust-housing on my T-4 is huge, so while very unrestrictive, I'm sure the turbo-lag will be much greater than it was with my old LG5. So, the MPFI's strong low-end and mid-range will help get the car out of the hole until the turbo is spooled up. Also, until the steel LIMGs became available for the 3x00s, I wouldn't have trusted a 3x00 top-end to boost. The MPFI manifolds are thicker too, which means less flex, not really a concern at the power levels I am playing around with, but I cannot recall ever working on a 2.8 or 3.1 that blew-out its' LIMG...


1989 SuperCharged 3800 Srs-II (First)Six-Speed GTU
1990 Turbo 3.4 5-Speed T-Type
1990 4.0L 4-Cam 32-Valve V-8 5-Speed Indy GTi (Project)
1990 Stock(!) 3.1 MPFI Auto Indy
1995 LA1/L82 4T60E Z-26
1995 3.4 DOHC Turbo 5-Speed Z-26
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Slinky
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Re: '90 "T-Type" Turbo 3.4 Five-Speed, 2nd Build

Post by Slinky »

I typically think of a good or better tune Not as a way to add more power four-speed but has stability and insurance see your engine doesn't burn up or get a lot of knock and cause it to ruin it.. I'll take your word for it but the research I've done 3400 injectors no matter what year could support an engine up to 270 hp without an afpr In less you are running them well over 100% duty cycle, And running them above 80% duty cycle from what I've heard will ruin them pretty fast that's why have 42lb injectors So that they are not working so hard and won't die and waste my money, But you seem to have done a lot of research and you seem to be very knowledgeable so I will take your word on all of this some of it is just hard to believe


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Re: '90 "T-Type" Turbo 3.4 Five-Speed, 2nd Build

Post by Rettax3 »

Slinky wrote:I typically think of a good or better tune Not as a way to add more power four-speed but has stability and insurance see your engine doesn't burn up or get a lot of knock and cause it to ruin it.. I'll take your word for it but the research I've done 3400 injectors no matter what year could support an engine up to 270 hp without an afpr In less you are running them well over 100% duty cycle, And running them above 80% duty cycle from what I've heard will ruin them pretty fast that's why have 42lb injectors So that they are not working so hard and won't die and waste my money, But you seem to have done a lot of research and you seem to be very knowledgeable so I will take your word on all of this some of it is just hard to believe
Thanks Slinky, considering the work you've done on your build, I appreciate that. Research is a big part of it, but experience is even more telling for me. I've done enough turbo projects and large displacement increases over the years, I'm pretty comfortable with what needs to be done, and what I can/cannot get away with, but I'm always building on a small budget too, so I end up cutting some corners other people might not, but I've rarely had issues over fuel control, and I've never toasted one of my built engines either. And I have yet to replace an injector on one of my turbo cars -two of them have gone bad on my GTU, but they were stock L67 Super Charged 3800 injectors, so I don't think they died because of duty-cycle, I'm running stock boost on that car, they both were starting to stick open enough to run their cylinder too rich. That problem could even have been caused by the old fuel filter, before I replaced it.

So from your research, I will be at the edge of the envelope for these injectors with my HP goals... I can live with that, since the car won't see maximum power output very often.

I don't usually drive my cars hard, at least not for long, but I'm sure that with some of them they are making enough power to shorten their lifespans if put into the hands of a die-hard racer for long, or someone who doesn't know how to drive them. I don't really consider it as a trade-off for reliability to get the extra power, in my mind it is more a case of knowing that if I am abusing my car now, I will have to put more maintenance into it later. But that is true with stock vehicles too, just less so. With gas prices as they are, pounding on my cars a lot isn't a great idea anyway: There was one day a couple of years ago that I was beating-up everybody at the stop-lights with my turbo Z-24 ('97 five-speed, 2.4 Twin Cam model with higher compression, and a little IHI intercooled turbo) so badly that I burned through almost 3/4 of a tank in a day, getting in the low teens for MPG, when that car usually pushes around 30 MPG! Tires are expensive now too, the price of them have doubled in the last ten-fifteen years. :x I would rather spend the money on something else.


1989 SuperCharged 3800 Srs-II (First)Six-Speed GTU
1990 Turbo 3.4 5-Speed T-Type
1990 4.0L 4-Cam 32-Valve V-8 5-Speed Indy GTi (Project)
1990 Stock(!) 3.1 MPFI Auto Indy
1995 LA1/L82 4T60E Z-26
1995 3.4 DOHC Turbo 5-Speed Z-26
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Rettax3
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Joined: Mon Oct 22, 2012 3:34 pm

Re: '90 "T-Type" Turbo 3.4 Five-Speed, 2nd Build

Post by Rettax3 »

Just a quick update on this, since I haven't had the opportunity to post for a while. The '99 GA GT PCM has been such a =@ with the BCM's (Body Control Module) anti-theft system working intermittently, I've had to spend half an hour repinning the connection harness to use a '96 Corsica PCM I had sitting around just to get the car to move around the driveway. Of course, the Corsy's PROM will run the 3400 injectors too rich, but it was okay to just start and move the car. I managed to pick up a '97 Venture's PCM today, and I'll drop that in as a permanent replacement to the GA junk. :x

I still have one oil-leak from the turbo's oil-supply line at the block to correct, and the instrumentation issue to contend with, and this car will be done (again :roll: ).
I also have a replacement (stock) hood to paint and install on my Yellow Indy. Then, I get to turn my attention back to my 3800 SC GTU, and the new update it is getting, but that is for a different thread! :wink:


1989 SuperCharged 3800 Srs-II (First)Six-Speed GTU
1990 Turbo 3.4 5-Speed T-Type
1990 4.0L 4-Cam 32-Valve V-8 5-Speed Indy GTi (Project)
1990 Stock(!) 3.1 MPFI Auto Indy
1995 LA1/L82 4T60E Z-26
1995 3.4 DOHC Turbo 5-Speed Z-26
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Re: '90 "T-Type" Turbo 3.4 Five-Speed, 2nd Build

Post by Koots »

Are you using hardline for your oil supply? I've very rarely seen it done, most just spring for the braided stainless hose, as it is flexible and easier to line up, which should help in creating a leak free seal.

I like what you are doing with this car and it sounds like you got a lot of nice potential projects. I'm subscribed for more turbo-porn :D


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Rettax3
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Re: '90 "T-Type" Turbo 3.4 Five-Speed, 2nd Build

Post by Rettax3 »

Koots wrote:Are you using hardline for your oil supply? I've very rarely seen it done, most just spring for the braided stainless hose, as it is flexible and easier to line up, which should help in creating a leak free seal.

I like what you are doing with this car and it sounds like you got a lot of nice potential projects. I'm subscribed for more turbo-porn :D
:D Thanks Koots, I always like hearing from you on these threads. :wink: Yes, I went with an aluminum hard-line for the oil supply. I used copper with brass connections previously, because the original steel-braided supply line on the LG5 had broken and because I wanted an adjustable oil-control valve and supply pressure-gauge, and I never really had a problem with it leaking. On this engine, I went with the 'O' (fully annealed) aluminum tubing, with stainless fittings where I could, but I had brass compression-rings in a few locations. The aluminum is too soft for the compression fittings, and it starts to collapse and leak after a little while, and it just keeps getting worse. Something acting as a flexible intermediate seal, like silicone, looks to be fixing this problem, but I haven't 'updated' the fitting from the block yet, so it is still leaking. Next time, I will either use the correct flare-type fittings for the aluminum (think aviation 'AN' style fittings, often found on pro-built race-cars), or I will go back to the copper tubing. Consider this a failed experiment in new procedures... :roll: Braided hoses would be fine, but hard-lines don't eventually dry-out and crack, nor do they wander around looking for a hot exhaust header to melt on, and I know how my luck tends to run with situations like that, so I try to eliminate the option for Murphy.

The Venture PCM is in, requiring only two wiring changes from the Corsica's PCM: The addition of one ground-wire (which the GA PCM had used, so the wire was already there), and the use of a common ground for the CMP (Cam Position Sensor) and 24xCKP (High-Res Crankshaft Position Sensor) (which I didn't have plugged in on the Corsy PCM, since it used a common spliced-in feed also from the ICM, %) which my harness did not support, and I didn't want to modify to use). It started the car flawlessly, and seemed to run it right. Hopefully, I can fix this last oil-leak and get the car back out onto the road for some more testing this week. Fingers crossed...


1989 SuperCharged 3800 Srs-II (First)Six-Speed GTU
1990 Turbo 3.4 5-Speed T-Type
1990 4.0L 4-Cam 32-Valve V-8 5-Speed Indy GTi (Project)
1990 Stock(!) 3.1 MPFI Auto Indy
1995 LA1/L82 4T60E Z-26
1995 3.4 DOHC Turbo 5-Speed Z-26
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Rettax3
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Re: '90 "T-Type" Turbo 3.4 Five-Speed, 2nd Build

Post by Rettax3 »

Update on this car. It has been almost a year, with very little progress on it unfortunately. I finally have the digital Cutlass Supreme instruments in and wired-up (mostly). I still need to solder-in the battery-constant + for the tripometer, and find a place to mount the Cutlass ECM to drive the speedometer and the Dakota Digital calibration-unit because of my royal =@ using the Cavvy transaxle. I also need to fab-up some kind of 7x RPM signal-generator for the tach, but that isn't super critical, especially since I still have the PCM running the engine thinking it is in neutral (which means a low RPM rev-limiter of ~4k).
Powering up...
Powering up...
The boost gauge needs to be put back into the instrument bezel too.
The boost gauge needs to be put back into the instrument bezel too.
I still need to make a lens for the instruments, finish setting up the rest of the indicator lights, and complete a few other small details.

I seem to have the oil-leak fixed, by using copper instead of the aluminum tubing I was using, but I am still not pleased with it, so I may try to track-down some stainless-steel braided hose as mentioned by koots, or go with flare fittings instead of compression. But the car is driveable as-is at least.

I have also had a problem with an electrical short for the ICM power, looks like some brittle insulation I will have to finish replacing. :roll:

It is finally getting close though, and maybe this summer I will be able to do some cosmetic clean-up work on it too. Mostly, I just want to get it back up to daily-driver status so I can get some use out of it and see a return on my investment. I would also like to get some more testing in on it, and see what this car can really do once I start dialing it up a bit. :twisted:


1989 SuperCharged 3800 Srs-II (First)Six-Speed GTU
1990 Turbo 3.4 5-Speed T-Type
1990 4.0L 4-Cam 32-Valve V-8 5-Speed Indy GTi (Project)
1990 Stock(!) 3.1 MPFI Auto Indy
1995 LA1/L82 4T60E Z-26
1995 3.4 DOHC Turbo 5-Speed Z-26
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