Engine and Transmission Tech

I am looking at a future project- a one off and nothing else.

Turbocharging our 3.4L V6. Minimal boost- 3-5 psi, probably closer to 3 psi. Minimal tuning with the understanding that there might be some glitches in the PCM. I looked at a 3.4L V6 in a Camaro about 6 months ago or so that they did this to with the remote turbo. This would be a minimal dollar budget item for the masses if desired.

So, remote turbo. 3-5 psi. minimal cost. Prefer teh boost to start working between 1,000 and 1,500 RPM and work strong until about 5-5,500 RPM.

Assuming that I want it to come on early and not outrun an otherwise stock motor, would something from a 2.3L Ford Turbo-coupe work well for this? I have access to one for Cheap. Cheap and reliable being the key words. Remote mount because I don't like heat up front and have thought for a few years about this....

That Twin Turbo Tiger in the sunbeam posting only fuels my fire... Well, that and having a Dodge 4 door Hemi V8 outrun me the other day at speeds over posted. ;-)

-This is a long term item and one of many considered-

-BMC.

Brian,
If you are researching into remote mount turbo systems, give this company a call, they have answered all my questions about turbo systems. STSturbo.com Below link

[www.ststurbo.com]

As for a dealer in your area, Wisconsin would be the closest to you I believe. Below link.

[www.kieperracing.com]

In short, I have a local friend that has those "SOB's"(Some other brand) cars as Carl would say, and like Jon your brother. He comes over to my house with his 87 (rare) slant nose turbo Porsche and his 2003 4WD somthing twin turbo Porsche, and asks me to drive them to see if there working OK. Take in mind he knows about the LS1 going into my TR6. He asked me if my TR6 will take his 87 turbo Porsche, I respond back with "could be close". Yesterday he came back with the twin turbo and asked the same question, I respond back with "well if I twin turbo like you, could be close, but would have a problem with tire spin.

Yesterday, I had one of my 15 year old twin sons with me riding shotgun when testing out the twin turbo. I live close to the outskirts of town and those back roads are close by. In first gear, hit the rev limiter before I could shift to second, once in second with no turbo lag hit about 110 mph(couldn't look at speedo), Third with no turbo lag went to 145 before I shut down. This car had head pain acceleration. My son was breathing fast with his eyes bugged out of his head saying "OH MY GOD". My friend just chipped the twin turbo and was getting around 535HP to the ground with 4WD. My friend is messing with me :-)

We all don't like something passing us up looking at their bumper including myself.

So I'm with you on fueling the fire.

Just might turbo here yet.

I would love to eat up that twin turbo at least up to 95 mph with the TR6.

By the way Jon's video LS1 924 sounded great in the autocross.


Calvin

Brian, turbo boost is very different from blower boost, so where 3-5 would be quite noticeable with a blower, with a turbo you probably want to aim a little higher, even with a high compression motor. I'd shoot for twice that, and if you find any signs of detonation add a cheap water/alcohol injection system (pressure/siphon bottle). You probably won't need it. Olds Jetfire 215's ran 6 psi with 11:1 and a windshield washer pump and probably didn't have as good of a chamber shape.

How much boost does your 2.3 turbo make with that engine? You're adding 50% displacement so you'd need roughly 15 to get 10. That's nowhere near accurate but is a starting point. Then also a rear mount is going to give you some cooling of the charge, which would allow you to go higher on the boost. An adjustable boost controller of some type would be a real good idea, that way you can size it a little bigger than you think you need and work up on it.

Jim

Brian,

Cheap power is pretty easy with a low boost turbo setup. Of the two turbo engines I've built neither one was expensive. I spent about $1650 on my 2.2L Turbo Dodge to make 250hp. That engine came with some pretty great stock parts like forged crank and rods. I used mere hypereutectic pistons though and never had a problem running a stable 17psi. That was a great engine. It did a good job of breaking the car though. Not that the lowly Dodge 4-door Omni is all that robust. LOL!

If it was me I'd fabricate the remote system myself. That would keep cost way down. I'm with Jim, 6-8 psi would be a good target to hit. The T3 out of that Turbo Coupe is typically a bit small for 3.4L but with the remote system it might be just the right thing because the exhaust gas volume will be down back there vs. right off the manifold. The other benefit from the remote system is no need for an intercooler because the charge is cooled on the way up to the intake.

Then you need to get some bigger injectors for the 3.4 or increase pressure to the stock injectors. I'd feel more comfortable with larger injectors though. You need a boost referenced fuel pressure regulator. You can get one of these off an old Dodge Turbo Caravan or something. They work fine for this application. You can use a Raising Rate Fuel pressure Regulator to change the fuel curve. That's kinda old school. I prefer a boost referenced ECU to change the fuel curve under boost though. I bet there are some guys out there building MegaSquirt boxes for this application in the Camaro community.

For boost control I'd build a simple manual boost controller with hardware parts. There are a couple details on this out in the Turbo Dodge community. It's basically a spring loaded ball check valve. I built one for about $7.95 Worked great!

Brian

As Jim stated low boost at low RPMs is really better suited for a supercharger. One of the issues with rear mounted turbo(s) is lag. I have driven a couple different C-6 Vettes with rear twin turbos. While they run quite strong, the lag is very noticeable, mainly at lower rpms. Once they spool up, your no longer in the 1000-1500 rpm range.
The best way to get low rpm boost out of a turbo, is to mount it as close to the exhaust manifold as possible. Also the smaller the turbo the quicker the spool up time. Use two small units, one for each bank!
Where turbos really start to shine is at high boost levels, usually above 14 psi. At the higher levels supercharger effciency really starts to fall off, while the turbo is just getting started!
Injector sizing can be kind of tricky, on a boosted engine. If you go to large on the injector flow rate, low speed driveability (normal city driving) can suffer. Due to the very short injector "on time"
For low boost levels 3-4 psi you could probably use your stock injectors, with an adjustable pressure regulator, and Mega-squirt.
If you want to use your stock ECM, you can add a fuel management unit (FMU). Although my tests have shown that the FMU dosn't start to change pressure much untill after about 3 psi of boost. They are best suited for boost levels above 5-6 psi. Also you can change the boost/fuel pressue ratio. For boost pressures under 10 psi a 3/1 or 4/1 ratio works well, depending on your base fuel pressure.
One advantage of the FMU is, you can use smaller injectors for better low speed driveabilty. Also fuel pressure pulsation is reduced under high loads, due to the higher fuel pressure. Just have to make sure that your fuel pump is up to the task of higher pressures.
While 3-4 psi is good, 8-9psi is better:-). I had my S/C B at 3-4 psi while I was dailing it in. This summer I cranked it up to 8.5-9 psi. It's amazing what another 4 or 5 pounds will do!
I use a Hallman manual boost controller. It's has a cermanic ball in it that is light and fast acting. The data-logs are showing a boost fluctuation of only 1/10 to 2/10s of a pound at full boost.

Bill



Edited 1 time(s). Last edit at 08/13/2008 01:44AM by MG four six eight.

Sounds like great advice guys. This is certainly a 3-4 psi idea with maybe something more in the future. No PCM reprogramming or piggybacking to start with. None. Maybe a little shot of water or something to take the pressure and hope the computer does not go so far out of its program that it runs aweful. The idea behind using a system that is not as good as it could be and gaining a small 30 BHP bump out of it is all I am looking for. There are far more interesting ways to get that out of the engine if its modified but I am going to take a few years to get things moved along.

I have a number of other items that I would like to perform when I get the chance. If the turbo is ever installed, I would certainly see how far up the ladder we could go before the computer gives too much trouble. I do not have time to install a megasquirt or other aftermarket controller, much less the money at the moment.

Just leaving the shop now- Working again on the MGB 3.5L FI harness. The main harness is starting to take form. Need to add relays and fuses tomorrow and start connecting the aftermarket ECU. I know the time this stuff takes- I certainly don't have time for this on my car now and can't afford to take it off the road again. :-)

-BMC.

couldn't you use nitrous oxide at the lower rpm's and when the boost pressure of the turbo's get up to the desired pressure simply turn off the nitrous? i have a magazine article in hot v w's with a 4 cylinder dragster and a power glide trans. that does this and his speed in the 1/4 mile is around 200. on the street though you will need to work on hooking up and not smoke the tires. i have a 66 sunbeam alpine i would like to put in a 3.4 engine with a turbo, and a 5 speed trans. i just installed a 94 S-10 rear with 3.42 gears and 28 spline axels, it bolted right in, my brother had 2 14" wheels 5"wide from a 65 buick skylark and they fit in the stock sheet metal no need for flares, and looks much better then the stock wire wheels that came off it.