Turbo a good idea for auto-x/ road race?

[67goatman455]

First off i am building a 1967 GTO, the plan is to keep it as light as possible with the use of fiberglass parts, and having a reasonable 500hp. I have had it set in my mind to power it with a 5.3l LSx motor and a 70mm turbo. The setup is coming together slowly, but surely.

I have been second guessing myself lately though, i'm really worried about having turbo lag, or dramatic power increases and having the car be unpredictable in corners. I have been thinking about switching to a Pro-charger instead so the power is more on demand.

The other option is to just achieve my goal of 500hp on just the motor itself. What are your thoughts/experiences?

Thanks for any help!

[badmatt]

If your second guessing.

me personally all motor!

[67goatman455]

All motor would be the most obvious but i'm just hung up on the fun factor of a turbo :D plus its super cheap to build and easy to add more power if i need it

[clill]

I would do all motor or do a Eaton style supercharger.

[67goatman455]

I would do all motor or do a Eaton style supercharger.

an eaton style is going to heat soak really bad. not very good for a road course i dont think

[camcojb]

an eaton style is going to heat soak really bad. not very good for a road course i dont think

that would depend on how well engineered it is. ;)

[67goatman455]

that would depend on how well engineered it is. ;)

any recommendations/ experience with them? any help to some good answers is appreciated!:thumbsup:

[SuperB70]

Turbo is great, just the damm lag and the heat load. And with just one turbo the drivebility is not so great on race applications. It more or less on/off. Softer power output by having two turbos.

Instead of useing Eaton, maeby you could use twin screw like Kenne bell, then build intake to house four Laminova intercoolers.

http://www.laminova.se/technology/intercooler

They are simply the best IC in the world.

I builded a big Hemi with a KB twin screw, blower factory told us that intercooler is not needed else than marine and tractorpulling applications.

But there is nothng wrong get your intake air temp down..

I'm currently playing with idea to build for laminova IC intake to my twin screw V10.

[GrabberGT]

Depending on your experience level and goals for the car, I'd say N/A. Autocross-wise, all the major players are N/A. Ridetech, DSE, Posi, Hobaugh, No-Limit... and with the exception of Maier (NASCAR 825hp) I think they are all relatively modest on power around 550hp. I think the important thing is to have a broad power band and a matching final gear ratio to get the most out of it.

Im still new to the game and learning how to use the little power I have 350-400. My last Autocross, I was drifting all over the place. Mine comes in late and my gearing leans towards hwy miles. It should be plenty for autocross though if I switch to a higher rear gear.

[Flash68]

Depending on your experience level and goals for the car, I'd say N/A. Autocross-wise, all the major players are N/A. Ridetech, DSE, Posi, Hobaugh, No-Limit... and with the exception of Maier (NASCAR 825hp) I think they are all relatively modest on power around 550hp. I think the important thing is to have a broad power band and a matching final gear ratio to get the most out of it.



Agreed on your last sentence.

Although most of those players you listed (with the exception of the No Limit truck) have quite a bit more than crank 550hp. :unibrow:

[clill]

an eaton style is going to heat soak really bad. not very good for a road course i dont think

Stielow's last three cars were built with Eaton style superchargers and all work great on the road course.

For autocross you are fighting for every little inch. and I think any lag from a turbo will kill your times.

[67goatman455]

well, i guess a change to a N/A build is in order unfortunately. :( I have been very excited about the sound/ feel/ and fun of a turbo for a couple years now.

Maybe two small turbo's wouldn't be so bad with lag?

I dont really see the point of going with a super charger because it seems that it would be more cost effective to go N/A. Since this is my first build for road racing/ auto-x i dont want to dump a lot of money into something that i may not like on the track.

Hopefully i wont lose all my motivation because of this change:mad:

[camcojb]

well, i guess a change to a N/A build is in order unfortunately. :( I have been very excited about the sound/ feel/ and fun of a turbo for a couple years now.

Maybe two small turbo's wouldn't be so bad with lag?

I dont really see the point of going with a super charger because it seems that it would be more cost effective to go N/A. Since this is my first build for road racing/ auto-x i dont want to dump a lot of money into something that i may not like on the track.

Hopefully i wont lose all my motivation because of this change:mad:

N/A is the easiest way to go, especially for the above use, and trying to keep the cost down. Any forced induction adds significantly to the cost.

[67goatman455]

N/A is the easiest way to go, especially for the above use, and trying to keep the cost down. Any forced induction adds significantly to the cost.

My turbo build was actually going to be very cheap. I have almost eyerything i need.

I guess i'm looking for success storys of a single turbo before i start scrapping that idea and building a N/A motor:thumbsup:

[Vegas69]

Autocross is all timing and making the fewest mistakes. Power that is not linear is a disadvantage. On a road course, the heat will creep up on you. 500hp is nothing to make naturally aspirated these days. GM has LS crate engines that do that.

[67goatman455]

Autocross is all timing and making the fewest mistakes. Power that is not linear is a disadvantage. On a road course, the heat will creep up on you. 500hp is nothing to make naturally aspirated these days. GM has LS crate engines that do that.

very good points.

[Flash68]

My turbo build was actually going to be very cheap. I have almost eyerything i need.

I guess i'm looking for success storys of a single turbo before i start scrapping that idea and building a N/A motor:thumbsup:

Whatever you do don't build a single turbo for what you are wanting to do.

It comes down to a twin turbo deal or NA. Single turbos are WAY too laggy. 2 smaller efficient turbos can be made to work, but as mentioned, you have to manage that heat.

I know lots of guys around here who track their twin turbo Porsches and from the factory smallish turbos it's a nice fairly linear power transition.

It depends on how serious you wanna get and how much you are really going to track it vs street drive it. Have to be honest with yourself and hopefully predict accurately how the car will be used. I say that because many of us change our usage after a car is built. ;)

[67goatman455]

Whatever you do don't build a single turbo for what you are wanting to do.

It comes down to a twin turbo deal or NA. Single turbos are WAY too laggy. 2 smaller efficient turbos can be made to work, but as mentioned, you have to manage that heat.

I know lots of guys around here who track their twin turbo Porsches and from the factory smallish turbos it's a nice fairly linear power transition.

It depends on how serious you wanna get and how much you are really going to track it vs street drive it. Have to be honest with yourself and hopefully predict accurately how the car will be used. I say that because many of us change our usage after a car is built. ;)

going to twin turbo jumps the cost up quickly. 2 wastegates, bov's, oil lines, more piping. just not an option i care to venture for.

I have finally started doing SCCA this year (only one event left till winter:( ) and i can say i am hooked already. The car will get driven as much as possible but the goal i have in mind is to be competitive on the track. And to one day be on the same track with some of the guys on this board!