necrocannibal

iTrader: (5)

Right now I am running a LME 408 with 317 heads and a Borg Warner S476 that put down 840 rwhp at 16 psi. I was told that getting some better heads would help but I am also reading that a 76 mm turbo is on the small side for a 408. I am trying to get to 1000 rwhp on pump 93 and meth so which direction would be best for me to try and reach my goals?

roastin240

iTrader: (13)

The way I would look at it, is the 76mm will only make so much power, even if the heads flow more, and your about maxed out with it. Additionally, 16psi is not THAT much boost and you could turn it up a bit with a larger turbo.

I vote turbo, then do heads down the road if your still not happy. I am not a 1000rwhp club guy, yet, but I have seen multiple setups with 317's make that power.

necrocannibal

iTrader: (5)

That right there is why I am asking people who know more than me because I have seen them also.

JoeNova

Heads won't help a turbo that is too small. Depending on the compressor, they can actually make it worse.

What turbine do you have? There are quite a few 370s and even a couple of 408s making 1000+whp on pump gas with a 76mm. You have to remember, there are LOTS of racing classes in this country that limit you to a 76mm turbo, and some of those guys are running 7s at 1200+whp. It usually requires a very well planned combo, though.

oscs

iTrader: (19)

Exactly. There are ton of factors here.. What transmission are you running?

necrocannibal

iTrader: (5)

Sorry guys my transmission is a T56. I can't not remember what they told me the turbine is on the car I will have to ask them this afternoon. I had a shop put it all together for me and I kind of gave them discretion on what turbo to use and all I remember about it is it's a S476. Also this is a 100% street car that will see a few trips to test n tune a year.

Ls1Ryan2002

If I were you I would go with the Turbo because you can't go wrong there, and also yes the heads would be something to do after the turbo.

JoeNova

If a shop built the car for you and you don't know anything about it, why not just give it back to them and tell them what you want?

necrocannibal

iTrader: (5)

I am going to find out the particulars on my turbo but what do you guys recommend for a 408? I'd like to stick with the Borg Warners because I have had good luck with this one and I know they are proven.

Can I send my turbo back to Forced Inductions and have them turn it into a larger one?

necrocannibal

iTrader: (5)

I talked with them about this shortly and I was told by them that I am far as I can go on pump gas with this set up. I am also trying to learn about this myself so I will be more in the know about what is going on instead of just letting someone else spend my money.

JoeNova

The big turbine S476 with a billet wheel and race cover should be able to make 1100whp on a 408 under ideal conditions. If you have anything smaller than the 96mm 1.32 T6, I would upgrade to that. They also have a 1.58 A/R housing that some of the guys use with the 4xx cube engine with a 76mm class turbo.

necrocannibal

iTrader: (5)

Here is what I know for sure, I just don't know turbine. It is a billet wheel, not a race cover and it is a T4 frame. I am not sure on the turbine or A/R but will find out today.

Thank you for educating me on this.

JoeNova

You might want to look into upgrading to a T6, although there is some work involved. LOTS of power can be made on a T4, but a larger engine pushes the turbine out of its efficiency range which can cause problems with compressor efficiency as well.

necrocannibal

iTrader: (5)

Can I just have someone cut off the T4 and weld a T6 in at the turbo or would I need to replace my crossover piping for that?

JoeNova

You can use the same crossover piping, but the T6 flange is wider, so if the piping has been shaped to fit a T4 flange, it will likely need to be reshaped for the T6 opening. Depending on how it was done, it can be either easy or very difficult.

necrocannibal

iTrader: (5)

Ok thank you for the info. I'll find out about my current turbo also. I am running a Huron Speed V1 A/C kit, maybe I can ask them if this is doable on their kit.

stevieturbo

Why not phone Jose and ask about the turbo upgrade and whether you can retain the T4.

I'm sure it is doable which would at least make it a simple bolt on swap

necrocannibal

iTrader: (5)

As soon as I find out exactly what I have I might give them a call.

TrendSetter

horsepower is all in your head

necrocannibal

iTrader: (5)

Well I trapped 138 in a full weight f body with it and I'm trying to get 145+ traps.