88 Buick Century LG5 3.1 Turbo swap

[turbobuick88]

Hey guys I'm new to the site so I thought I would share my LG5 swap with you and hows it going. I will post up progress also. The LG5 as most of you know is the Gran Prix turbo motor. I pulled this one out of a badly beaten up one with warped heads and intakes from being overheated multiple times But the block was good which is stronger because it has more nickle content than just a standard LH0 3.1. I also kept the forged crank. Everything else was pulled. I started with new factory spec LG5 connecting rods, pistons, and cam. I then bought a 90 LH0 for the heads and intake with only 45k. I ported and polished the heads and intakes(gasket matched) and ported and polished the TB. The center "flex pipe" turbo connector was shot and so whats the T25 turbo (burned lots and lots of oil) Since I'm looking for more low-end torque The new turbo will be a T3/T4 running 8-10 PSI. I am recreating the center turbo piece and have a 4" down pipe for the turbo fabbed up. For fuel delivery the factory LG5 injectors were tossed for 3800 S/C injectors, but the LG5 fuel pressure regulator remains. Here is the engine as it sits right now(on my ghetto shopping cart engine stand lol):





****UPDATES****
I now have a LG5 intake thanks to my friend David so that will be going on shortly. I have the center manifold all done and the down-pipe will be done this week. I have rebuilt a 30k TH125C with all new bands and clutches and a shift kit and a few other mods to decrease shifting time, increase band pressure and line pressure. This should make the 125 handle the power. here are few pics of the progress. I hope to have it in the car and running sometime in December.



The Center manifold with turbo flange and waste-gate port wrapped and painted.



with the manifold, waste-gate and turbo installed finishing up the waste-gate dump this week also

[RedZMonte]

Nice, i like the motor. my '90 TGP ran strong. dunno what the specs on that TD04 are but you may wanna find something bigger, the TD04 is pretty small. The stock T25 is, i think, to small for the motor as is and it had larger wheels/housings for a T25. Keep the pics coming as it goes, i like seeing swaps lol 4" DP is HUGE... plan on running desiel? lol JK

may wanna check the "W-Body" forum. there are a few guys with the older TGP parts floating around there.

Shane

[turbobuick88]

Lol thanks! the downpipe is only like 6" long but turbos don't like back pressure so its never two big! The TDO4 will be big enough for the RPM band it will be running at. But I'm also wondering what I could do for a better intake from a newer engine for better flow if I can't find the TGP intake?

[Fireball]

Very very cool! I'm going to be watching this one!

[robertisaar]

Nice, i like the motor. my '90 TGP ran strong. dunno what the specs on that TD04 are but you may wanna find something bigger, the TD04 is pretty small. The stock T25 is, i think, to small for the motor as is and it had larger wheels/housings for a T25. Keep the pics coming as it goes, i like seeing swaps lol 4" DP is HUGE... plan on running desiel? lol JK

may wanna check the "W-Body" forum. there are a few guys with the older TGP parts floating around there.

Shane

correct, T25 was undersized even for a stock LH0/LG5, it's why they can build considerable boost just off of 2000RPM. some of the smaller T04E's are a nice match.

Lol thanks! the downpipe is only like 6" long but turbos don't like back pressure so its never two big! The TDO4 will be big enough for the RPM band it will be running at. But I'm also wondering what I could do for a better intake from a newer engine for better flow if I can't find the TGP intake?

if you want to run a gen3 intake, you'll need at a minimum a gen3 lower intake as well, possibly the heads too, i can't remember if those are a requirement or not.

i'm not gonna say anything about the buick 6 logo.

[turbobuick88]

if i can get away with upper and lower Gen III intakes with out swapping the heads that would be nice.

lol what about the power 6 logo? its a V6 boosted and going in a Buick!

[TiredGXP]

and the TDO4

It's a bit blurry, but the part number on the compressor looks like 49177-01310. If so, what you have there is the 09B compressor. That compressor is significantly smaller that any GT25 turbo - it only flows 17 lb/min. This is pretty much the smallest Turbo that Mitsubishi makes - roughly a GT15xx turbo.

If the part number is 49177-01810, what you have is the 11B compressor, which flows about 20 lb/hr.

TD04 turbine is very small, with a tiny A/R. The first part number identified above is, in Mitsubishi speak, a 5 cm^2 A/R - roughly equivalent to 0.35 as Garrett calculates things. The second part number listed above only has a 4 cm^2 A/R.

If you want to stay with a Mitsubishi unit for the 3.1, you're probably going to have to move up to a 20G compressor with an 8CM^2 TD06 turbine.

[turbobuick88]

Tiredgxp: after you told me about that I looked into the TD04 a bit more. I looked into some flow maps and saw how quickly it will actualy spool. especially with built 3.1 huffing into it. So what do you guys recommend I go with? I have a T-25 and a T3/t4 laying around. I have about $200-
$300 to spend and it will have to spool just after 2500 rpm or before 3000 rpm

[TiredGXP]

T3/T4 - 50 trim compressor is a good match, 60 trim would be good too.

[turbobuick88]

I have a t3/t4 t04e will that be sufficient?

[TurboGTU]

Yes. that will do. I think the valve cover logo is sweet.

[turbobuick88]

Yes. that will do. I think the valve cover logo is sweet.

cool I have too many turbos lying around now! Thanks! It kinda sucks cause after I put the coolant lines on it will half be covered up.

UPDATE: TH125HC 3speed (still need to figure out how to get more line pressure)is now done and ready to be mated up to the engine! Also has trans oil cooler.

[turbobuick88]

Check out the new updates on the first post