Kevvan

Hello!

i am currently building a Bmw with a lm7 5.3l
soon its time for the engine to go in and i have to decide whatever to turbo it or not.

i want a turbo but the problem is that i will register the car with the new engine, and where i live we have some rules that i has to follow, with the weight of this car it cant have more than ~400bhp, and a minimum of ~5 psi boost if going turbo.

And that is the problem. Is there any turbo small enough to not go over 400hp at 5psi?
And it has to be on e85..

have a good day!

RonSSNova

iTrader: (3)

What do they do? Put it on a dyno?

Kevvan

I have to do that and show them a dyno paper

Bbknucks

Put whatever turbo you want and spring the gate so it only makes whatever boost/power you need it to... print that dyno sheet...then send it to the moon

Bbknucks

Where is this at anyway?

Kevvan

Sweden
yes that was my thought but i dont know if it will make much more than 400hp on 5psi boost

Bbknucks

Ahh I see...

If your tuner is cool you can play with timing and boost to make whatever power you need i suppose... then actually tune it up

Kevvan

oh and i forgot, The turbo has to have a maximal capacity of 50% more power than the car should hove, so 400+50%=600hp, Can someone recomend a turbo?

SKEETS64IMPALA

This is a unique one. So you can have an allowed maximum of 400 wheel horsepower on a Dyno of your choice using a stock lm7? But you can use a maximum of 5 psi with a turbo that's rated at no more than 600 horsepower?

Who gets to rate the turbo max power level?

I thinks it's basically going to come down to the base horsepower rating of the n/a 5.3. Then put 5lbs to it and see what it makes. I was thinking s366 but I'm sure that turbo is going to be capable of more than 600. Can you just pick a small turbo and cam it to make the max power?

ScottStaypuff

I would use your stock camshaft or a small aftermarket cam, like a "truck cam" to give you good area under the curve. A TBSS intake would be a good match if you can fit it. Or an LS6 intake or any other stock type long runner intake. You want to aim to keep NA horsepower at or below 290 then 5 psi will get you 400hp. Most any turbo big enough to supply 5psi to your 5.3 will give you around 400hp if you start with ~290hp NA. Just depends how bad you want to cheat and raise boost after you get your 5psi dyno!

My thought is maybe the VS Racing gen 2.5 with .96ar. which should be responsive and pretty cheap and have room to grow.

https://turbo4less.com/product/vsr-7875-g2-5-series/

Another suggestion if you want more response but are ok with a little less overall power (again at 5psi it would be about the same power and more responsive than the 7875 but 15 or 20psi it probably wont hold on as long) is the VS 70/70 turbo.

https://turbo4less.com/product/vsr-7...illet-t4-copy/

SKEETS64IMPALA

That 70/70 is rated at 1100 Flywheel so it's a no-go by rule of the gubment.

gsteele

How often do they check your setup? Have one turbo for when you take it to be inspected and swap it out for a different one to drive around with.

ScottStaypuff

Yeah, thats a tough one. I think VS is optimistic with its claims but are we talking crank or wheel horsepower? I would think this turbo is probably close to a 600whp turbo. There's a whole thread on it if OP wants to dig it up.

OP, are there any enthusiast groups near you where someone has succesfully done this? They may have better advice!

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