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Performance, Brainstorming & Tuning Talk about modifications, or anything else associated with performance enhancements. Have a new idea for performance/reliability? Post it here. No idea is stupid! (please use Detailing and Appearance for cosmetic ideas)

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Old 08-08-2005, 08:24 PM   #11
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Yea i'll vouch for the LG3. I've got one, 205k still goin strong. And i beat it to all hell, several times i've taken it over the redline with no adverse effects. Obviously this isn't a daily occurance, but it'* possible. The only major service ever done to my engine was the timing gear and chain. Other than that it runs perfect. Wish i could say the same for it'* tranny, i'm on my 3rd one.
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Old 08-09-2005, 01:15 AM   #12
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Originally Posted by jr's3800
I have heard of the old 3.8'* easily making 200Hp and 280 ft lbs with decent pistons and decent cam... The 3.8'* could be torquers for sure... But this goes for the conventional lifter 3.8..
Please elaborate on this 200hp and 280lb of tq
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Old 08-09-2005, 09:47 PM   #13
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I posted a topic here somewhere last year about a LG3-3 a LeSabre T-type owner was building or built I should say. I just cant remember the subject I used for the post or if I threw it up on some other post about performance

Also one about a turboed LG3-3 in a Fiero

Anyhow he had comp cams do a new cam from a blank so there is now a part number for that cam I just dont have a link The cam is most of what causes the low HP RPM. Its not the largest throttle body either but theres not much to do about that. The turbo Regal guys do not use high RPM'* either, in fact I think they shift around 4000 with the production engines, stage II engines might be different but not the production street car engines. I have a turbo Riv engine ( same as turbo Regal except manifold layout) and they do not have large tubes either. I believe this actually helps in the low RPM torque, thats what a old 3.8 needs to be built for, more torque and low RPM power curve, because that is how it was designed - its a B U I C K thing.

Heads can be ported

The rear exhaust manifold can have an obstruction near the down pipe. Its the easiest exhaust in the world to remove. If you take it out and look up in the rear manifold you will see the problem and a long shank burr in a die grinder can work wonders and its a quick job, just wear safety glasses because your kinda vulnerable down there.

The turbo guy put aluminum heads on the LG3-3 block. He also said the crank and rods were strong enough as they were, as good as the RWD turbo engine had I believe. Its probably a weaker block though.

pistons I cant remember anything about but I believe both builds used other than stock pistons.

Absoultely nothing off the later 3.8'* will fit on the early 3.8'*.

Its not the most perfected of the 3.8'* but it sure is the purtiest !

Hope this helps, its all I know and its not hands on, its from reading and asking questions, all my engines are still stock, except for the rear manifold issue and intakes/air filters.
86 LeSabre coupe, 90 Regency, 90 Ciera Cruiser and the 97 LSS have a new stable mate............06 G6 GTP coupe, white with taupe & black interior
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Old 08-20-2005, 07:23 PM   #14
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I've decided to go the custom route. Im going to match and mill my heads at least, since I dont have the knowledge to do a full port job.

Im going to look through boneyards and Ebay and scavenge what I can for a custom turbo setup.A guy I know has a T25 in good cond for sale, but I dont know if thats what Im looking for.

Does anyone know what has to be changed in a turbo setup? My compression is only 8.5:1 so I was thinking like starting off with around 10 PSI boost and seeing where I go from there.

I know Ill need:
Bigger Injectors
Custom Piping

And definately a beefed up transmission with preferably a posi unit.

Sorry, I dont know t hat much about custom turbo apps. Thanks for any help!
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Old 08-20-2005, 07:36 PM   #15
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Aside from the larger injectors, a beefier, higher-flowing fuel pump may be in order.

Staffer "Merlin 91/97" had a turbo setup done on his '91, and I believe he'* running considerably less than 10psi, or intends to, anyway. I think he'* your best candidate in terms of expertise.

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Old 08-21-2005, 03:15 AM   #16
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The pics of Merlins install look very good, I only wish I had that much room under the hood. My installation is similar although I am not running an intercooler, and limit boost to around 8 psi. Injectors and a fuel pump will be needed. You will need to relocate the vent line on the throttle body for the PCV system to the intake ahead of the compressor. Merlins install looks like a blow through the MAF and I ran mine like that for a year and then relocated it to the intake side of the compressor, but it seems to make little difference, at least at the moderate boost levels. You will need some device to prevent boost getting to the vacuum modulator if you have one. I used a check valve from an air compressor that vents the modulator line to atmosphere when the check valve operates. I also added a check valve from a vacuum brake booster to the plumbing for the PCV valve itself as the PCV does not seal completely under boost. Oil for the turbo was drilled and tapped into the oil filter adapter from the same passage that connects to the oil pressure sender. The drain line is 3/4" and was welded to the pan. Try to keep as high as possible to get above the oil level. I also run a 160* thermostat to help reduce the detonation potential. The aftermarket A/F and timing items seem like a good idea but I am running the factory ECM with a GM Tuners chip (still in the process of refining). If you ECM is similar to mine, it can only read air flow up to 170 gr/sec, and you will exceed that somewhere around 4-5 psi of boost, although that may vary a bit. Premium fuel will be required.

The T25 turbo may be a little on the small side, a T3 would be better, but it will spool very quickly and at moderate boost levels it may work fine. You may want to get the info. off the turbo and look at compressor maps for that model to see where the expected performance will fall in it'* operating range. Precision turbo, Majestic turbo and others have the compressor maps online.
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