V8 Turbocharging to gain 100 horsepower

[JBrady]

I am strongly looking towards turbocharging my 1999 Lexus V8 with a goal of adding 100hp.

A 100hp gain via turbocharging will take aproximately 5psi of boost which may be usable without intercooling depending on the compressor and ulitimate packaging. It should also work with the stock engine and transmission.

My current plan is to utilize one of Comp Turbo's oil less turbos in a low/remote mount. This may allow for the current catalyst and emission components to remain with the goal of passing state inspection.

As things develop I will try to keep the forum up to date.

 

[BlackUZZ31]

i went from 150rwkw to 215rwkw with 7psi supercharged running a motec m800 on a 96+ 1uz, 100hp at the crank maybe but an extra 100 at the wheels 5psi wont be enough!

 

[stevechumo]

Do it John. It should be an interesting project. I think stock internals can handle 9 psi if you have good tuning with upgraded fuel system.

 

[JustenGT8]

i went from 150rwkw to 215rwkw with 7psi supercharged running a motec m800 on a 96+ 1uz, 100hp at the crank maybe but an extra 100 at the wheels 5psi wont be enough!

Turbo 5psi > SC 5psi

But I agree 100hp crank is possible 100rwhp is unlikely

 

[JBrady]

I am talking crank not wheel horsepower. 5psi being 1/3 an atmosphere gives a simplified 1/3 gain in power. Stock power is 300 crank.

Now, that said, boost is only a measure of the pressure in the intake manifold and the true measure of supercharging is the increase in mass flow.

IIRC... David aka "Lextreme" achieved 325rwhp on his twin turbo 1st gen LS400 on only 8psi. Stock was roughly 175rwhp for a gain of 150rwhp or a gain of 18.75rwhp per psi. 1st gens make apx 175rwhp per atmosphere so 1/3 (5psi) should/would give apx 58rwhp or 12rwhp per psi of atmosphere. David achieved substancially more (nearly 19rwhp/psi) with stock 1st gen exhaust manifolds.

My initial goal is roughly 100hp crank or 80rwhp and I would not be surprised if I get there with less than 5psi. My engine makes apx 230rwhp stock = ~16rwhp per psi of atmosphere.

Quick "rounded" conversions for our kilowatt readers

100hp = 75kW
80rwhp = 60kW
18.75rwhp per psi = 14rwkW per psi

 

[JustenGT8]

pfft I made 355rwhp on only 6.5psi with my TT setup

stock ECU will be the limiting factor

 

[JBrady]

pfft I made 355rwhp on only 6.5psi with my TT setup

stock ECU will be the limiting factor

Justen, yes, I agree, was going to use your example except that you have a manual transmission (good for probably 25hp on the stock unboosted engine) and you have the golden touch for tuning.

So, in your case, you probably started with a combo that would make 200rwhp/150rwkW... added 6.5psi and gained 24rwhp per psi of boost. David gained nearly 19rwhp... both of you running the early heads and intake manifold. David with the stock exhaust manifold and you with your excellent compact turbo headers. Mine is of course the VVTi version with heads that flow like ported first gens and a very good intake manifold. Stock exhaust manifolds are tri-y design giving a combo that should out perform the 1st gens in terms of power gained per PSI. I can manage 20rwhp/psi I will gain 100rwhp on 5psi. Who knows, I might do better!

I agree about the tuning part as well and JeffTsai who has built the stock A650E to survive 800rwhp has also done it with the stock ECU and the piggyback Greddy eManage. This is the route I am planning. Not the 800hp part... the eManage part. Well... who knows... power is addicting and the quest never seems to end now does it?

 

[ruishy1]

i would still add an intercooler, even a small one in an inner wing or something.
Even a cheap ebay intercooler will help.

Oh and stop asking about it and do it already

 

[JustenGT8]

Ah, Emanage will make a decent difference. I didn't factor in its the later engine either, which will respond better again to boost. 100rwhp with the Emanage won't be a problem, still might take a little more than 6psi but either way your goal of a sensible increase in power with a simple setup looks sound to me

 

[XR8tt]

Yep its dependant on turbo selection.. Boost is really just a guide...
Higher compression will help.. Though more critical tune wise ...

 

[stevechumo]

I'd also like to add that rwhp is also another guide. It doesn't tell exactly how fast/powerful the car is. Talking about HP, I think the car makers use bhp as a general guide to measure engine power for a reason.

Bhp measurement can be a standard power measurement due to its repeating value with lesser variables that change the output value. On the other hand, although the rwhp can give a real hp number, it actually can't. An example would be one dyno machine can give a different number from another dyno machine. And the dyno tech can manipulate it to get higher or lower number. Therefore, it can't be compared between rwhp from the dyno.

 

[SC400TT]

John, glad to hear you are going to do it. Looking forward to yet another FI Lexus on the streets!

Ryan

 

[XR8tt]

You WILL find torque is so much lower too..
An extra 100 h.p would be kinda hard to achieve to a point..
Like any good forced induction .. Making power is easy..
Limiting the power with require a good wastegate...
A 400 h.p Forced engine is much quicker than 400 N/A engine..

 

[JBrady]

XR8tt, I think what you are saying is the torque will see a strong increase due to the boost. I agree. For the same reason a FI engine with low/mid range boost will have much more low/mid RPM torque and will therefore be faster than an equal peak horsepower vehicle in any contest that includes low/mid RPM.

 

[JBrady]

I am about to go to the air/fuel section for piggyback recommendations. I emailed Greddy since they do not list a Lexus/Toyota V8 option... only the 4 and 6 cylinder cars

Hopefully one can be adapted but if not what else would you guys like to recommend?

 

[stevechumo]

AEM has F/IC-8 for the V8. It's universal, but it should work well on the LS. I read somewhere some SC4 guy has been using it. Some Tundra guys also use it.