Turbo setup (FD) for road courses?
12-22-05, 03:57 PM
#26
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For road courses you really have two options available:
-non-sequential stock type twins
-small single turbo
On a road course you want quick throttle response and minimal turbo lag, so that means NO t-78’s, or T-88’s here. With some bolt-ons a good fuel system, non-sequential twins and proper tuning you can make 400+ hp reliably out on the course. If you go with the single setup you are probably going to want to limit your search to ball barring turbos, they offer quicker spool up which you will need.
There are some other things you should consider, if you haven’t already upgrading your intercooler is a must for most track cars. Regarding your intercooler, there are some things you should keep in mind. A front mount is not necessary; in fact a larger stock-mount will probably work better than a FMIC. The reason being, that there is significantly less distance of piping for the air to travel through, this means quicker throttle response, which you will need coming out of every corner.
One other thing is you might consider getting a ported engine. On the track, your rpm’s are consistently high, with a ported engine you will make just a little more hp up there in the higher rpm range, which is where you spend most of your time on a road course.
-non-sequential stock type twins
-small single turbo
On a road course you want quick throttle response and minimal turbo lag, so that means NO t-78’s, or T-88’s here. With some bolt-ons a good fuel system, non-sequential twins and proper tuning you can make 400+ hp reliably out on the course. If you go with the single setup you are probably going to want to limit your search to ball barring turbos, they offer quicker spool up which you will need.
There are some other things you should consider, if you haven’t already upgrading your intercooler is a must for most track cars. Regarding your intercooler, there are some things you should keep in mind. A front mount is not necessary; in fact a larger stock-mount will probably work better than a FMIC. The reason being, that there is significantly less distance of piping for the air to travel through, this means quicker throttle response, which you will need coming out of every corner.
One other thing is you might consider getting a ported engine. On the track, your rpm’s are consistently high, with a ported engine you will make just a little more hp up there in the higher rpm range, which is where you spend most of your time on a road course.
12-22-05, 04:06 PM
#27
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I already planned on doing exactly what you suggested with the IC. I'm still debating about porting or not. I know it'll give me more hp, but right now I'm not sure if my budget will be able to handle the stresses of going through ported engines time and again. It's still up in the air.
Other things I'm still considering are:
suspension setup
what wheel and tire sizes that will match up with my needs
fuel system/ecu specifics
Other things I'm still considering are:
suspension setup
what wheel and tire sizes that will match up with my needs
fuel system/ecu specifics
12-22-05, 04:20 PM
#28
Rotary Enthusiast
A single turbo is a good way to go if you have a track only car. I'd probably switch to a small/medium size single turbo if I didn't want to keep my car street legal and streetable.
However, I've had great luck with my stock twins at the track and the great boost response is a big help on slower corners.
If I were you I'd try the stock twins to start and then upgrade if you get more power hungry.
Crispy ran the stock twins for YEARS and YEARS at the track with good results. He recently went single and I think he's still sorting out some issues. He'd be a good one to ask about the differences.
However, I've had great luck with my stock twins at the track and the great boost response is a big help on slower corners.
If I were you I'd try the stock twins to start and then upgrade if you get more power hungry.
Crispy ran the stock twins for YEARS and YEARS at the track with good results. He recently went single and I think he's still sorting out some issues. He'd be a good one to ask about the differences.
12-22-05, 04:26 PM
#29
Hey Paul, hows it going out there, this is Andrew from MN. I remember you from NRR.
Some of what I'm going to say is a repeat of what was already said, but here it is anyway. You really have many decisions to make, and you are wise to come up with a goal beforehand and research, research, research.
I made a tree for the decisions regarding the turbo system, showing what I'm going to talk about. There's also lots of other decisions to make with their associated trees too, but this is just for the turbo setup itself. I have the design document from last year for my car that I could email you if you want to check it out too. It's pretty specific for my car, but you might be able to get some ideas from it.
Here's my conservative suggestions (just my opinion) based on your potential goals for a street/HPDE FD:
If you want to keep the car very streetable, use twins in sequential mode.
Positives:
If you get either upgraded or 99 spec turbos you will make alot of boost instantly at low RPM and it will be fun to drive on the street.
300+rwhp is obtainable. (A little more for upgraded twins)
Least expensive, at least in terms of up front costs, since you get labor free.
Least work to do overall.
Emissions isn't an issue.
Drawbacks:
On the track the turbos will probably run out of breath in the high RPMs.
You will need to pay very close attention to removing heat.
It would be wise to run them at a maximum of 10-12 lbs for longevity/heat reasons.
Sequential system is very complex and prone to issues, especially when pushed hard on the track.
Examples: Damian's street car, Majik's car, DamonB's car and many many others.
If you want to make a little more mid-range power, and lose the complexity of the twins at a cost of some low end power, go parallel.
Positives:
This will still will be pretty fun to drive on the street.
315+rwhp is obtainable. (A little more for upgraded twins)
Still inexpensive, since mainly it involves removing things.
No more transition in the middle of a corner.
Emissions isn't an issue.
Drawbacks:
On the track the turbos will probably run out of breath in the high RPMs.
You will still need to pay attention to removing heat.
It would be wise to run them at a maximum of 10-12 lbs for longevity/heat reasons.
Since the sequential system is gone, this would be fairly reliable.
Examples:
GoodfellaFD3S and many others.
If you want to make a little more high end power, and lose the weight and complexity of the twins alltogether, go small single.
Positives:
This will still will be pretty fun to drive on the street as long as you get up in the rpms a little.
330+rwhp is obtainable.
Engine bay is cleaned up some.
The turbo system would be fairly reliable. (Depending on boost control system)
Drawbacks:
On the track the turbo will probably run out of breath in the high RPMs.
You will still need to pay attention to removing heat.
It would be wise to run it at a maximum of 15 lbs for longevity/heat reasons.
It will be hard to make emissions.
Example: Anyone with a RX-6.
If you want to make substantially more high end power, go with a medium size single.
Positives:
To be fun on the street you will need to get the rpms up into the 3500 range.
375+rwhp is obtainable.
Engine bay is cleaned up.
The turbo system would be fairly reliable. (Depending on boost control system)
The turbos will probably not run out of breath in the high RPMs.
Drawbacks:
You will still need to pay attention to removing heat.
It would be wise to run it at a maximum of 15 lbs for longevity/heat reasons.
It will be very hard to make emissions.
Might need a ported motor to spool this well.
Examples:
My car, Crispy's car, and many, many others.
If you want to make a track only car, that produces substantially more power, go with a big single.
Positives:
Realisticly this won't be alot of fun on the street.
450+rwhp is obtainable.
Engine bay is cleaned up.
The turbo system would be fairly reliable. (Depending on boost level and boost control system)
The turbo will not run out of breath in the high RPMs.
Drawbacks:
You will still need to pay attention to removing heat.
It will be near impossible to make emissions.
You will have alot of other things to modify to make this drivable on the track.
Expensive.
Need a large port to spool this.
Examples:
Damian's Yellow beast (R85) Fritz's Killer Bee (T78/76) Max Cooper's Car (R85) and many others.
There's also a few other things, which I'm not going to go into, like parallel 30R's, variable vane turbos etc.
Now to the actual important part....
Don't pay any attention to a specific number of horsepower. The power of the car is only a fraction of the whole picture in a road course environment. Pick a system (and indeed engineer the whole car) around a idea of what you want to do with the car, not that you want to get to 378rwhp.
Fritz and Damian's track cars beat up on pretty much everybody even though they're probably only making 330-360rwhp mainly because of their driving skill, obtained through talent and experience, and because of all the other modifications done to the car.
That said, I went with the A-Spec 35R kit this past winter when I had to make the same decision as you, and I'm not unhappy with the choice. My goal was to make the car 70% track and 30% street. As such, my car isn't the best street car. For one I need to get to 3000-3500 rpm before it starts to make alot of power, but given my goals that isn't an issue. If it was 4500-5000 (like it might be if I went big single) that would be unacceptable to me. If anything, my clutch hurts street driving capability the worst, because of the wicked short engagement.
Yet, on the track I'm able to keep up with 90-95% of the other cars at the HPDE days in terms of power even at 10psi of boost. (I do have a street ported motor as well as alot of other mods.) My car pulls quite hard all the way to redline without any drop off as well. I'm sure there's more power left in the tuning, and upping the boost, but it's plenty fast right now. There's lots of other things to do with tires, suspension, weight reduction, aero etc. etc. that I would change before I decide to do anything with the power of the car.
Some of what I'm going to say is a repeat of what was already said, but here it is anyway. You really have many decisions to make, and you are wise to come up with a goal beforehand and research, research, research.
I made a tree for the decisions regarding the turbo system, showing what I'm going to talk about. There's also lots of other decisions to make with their associated trees too, but this is just for the turbo setup itself. I have the design document from last year for my car that I could email you if you want to check it out too. It's pretty specific for my car, but you might be able to get some ideas from it.
Here's my conservative suggestions (just my opinion) based on your potential goals for a street/HPDE FD:
If you want to keep the car very streetable, use twins in sequential mode.
Positives:
If you get either upgraded or 99 spec turbos you will make alot of boost instantly at low RPM and it will be fun to drive on the street.
300+rwhp is obtainable. (A little more for upgraded twins)
Least expensive, at least in terms of up front costs, since you get labor free.
Least work to do overall.
Emissions isn't an issue.
Drawbacks:
On the track the turbos will probably run out of breath in the high RPMs.
You will need to pay very close attention to removing heat.
It would be wise to run them at a maximum of 10-12 lbs for longevity/heat reasons.
Sequential system is very complex and prone to issues, especially when pushed hard on the track.
Examples: Damian's street car, Majik's car, DamonB's car and many many others.
If you want to make a little more mid-range power, and lose the complexity of the twins at a cost of some low end power, go parallel.
Positives:
This will still will be pretty fun to drive on the street.
315+rwhp is obtainable. (A little more for upgraded twins)
Still inexpensive, since mainly it involves removing things.
No more transition in the middle of a corner.
Emissions isn't an issue.
Drawbacks:
On the track the turbos will probably run out of breath in the high RPMs.
You will still need to pay attention to removing heat.
It would be wise to run them at a maximum of 10-12 lbs for longevity/heat reasons.
Since the sequential system is gone, this would be fairly reliable.
Examples:
GoodfellaFD3S and many others.
If you want to make a little more high end power, and lose the weight and complexity of the twins alltogether, go small single.
Positives:
This will still will be pretty fun to drive on the street as long as you get up in the rpms a little.
330+rwhp is obtainable.
Engine bay is cleaned up some.
The turbo system would be fairly reliable. (Depending on boost control system)
Drawbacks:
On the track the turbo will probably run out of breath in the high RPMs.
You will still need to pay attention to removing heat.
It would be wise to run it at a maximum of 15 lbs for longevity/heat reasons.
It will be hard to make emissions.
Example: Anyone with a RX-6.
If you want to make substantially more high end power, go with a medium size single.
Positives:
To be fun on the street you will need to get the rpms up into the 3500 range.
375+rwhp is obtainable.
Engine bay is cleaned up.
The turbo system would be fairly reliable. (Depending on boost control system)
The turbos will probably not run out of breath in the high RPMs.
Drawbacks:
You will still need to pay attention to removing heat.
It would be wise to run it at a maximum of 15 lbs for longevity/heat reasons.
It will be very hard to make emissions.
Might need a ported motor to spool this well.
Examples:
My car, Crispy's car, and many, many others.
If you want to make a track only car, that produces substantially more power, go with a big single.
Positives:
Realisticly this won't be alot of fun on the street.
450+rwhp is obtainable.
Engine bay is cleaned up.
The turbo system would be fairly reliable. (Depending on boost level and boost control system)
The turbo will not run out of breath in the high RPMs.
Drawbacks:
You will still need to pay attention to removing heat.
It will be near impossible to make emissions.
You will have alot of other things to modify to make this drivable on the track.
Expensive.
Need a large port to spool this.
Examples:
Damian's Yellow beast (R85) Fritz's Killer Bee (T78/76) Max Cooper's Car (R85) and many others.
There's also a few other things, which I'm not going to go into, like parallel 30R's, variable vane turbos etc.
Now to the actual important part....
Don't pay any attention to a specific number of horsepower. The power of the car is only a fraction of the whole picture in a road course environment. Pick a system (and indeed engineer the whole car) around a idea of what you want to do with the car, not that you want to get to 378rwhp.
Fritz and Damian's track cars beat up on pretty much everybody even though they're probably only making 330-360rwhp mainly because of their driving skill, obtained through talent and experience, and because of all the other modifications done to the car.
That said, I went with the A-Spec 35R kit this past winter when I had to make the same decision as you, and I'm not unhappy with the choice. My goal was to make the car 70% track and 30% street. As such, my car isn't the best street car. For one I need to get to 3000-3500 rpm before it starts to make alot of power, but given my goals that isn't an issue. If it was 4500-5000 (like it might be if I went big single) that would be unacceptable to me. If anything, my clutch hurts street driving capability the worst, because of the wicked short engagement.
Yet, on the track I'm able to keep up with 90-95% of the other cars at the HPDE days in terms of power even at 10psi of boost. (I do have a street ported motor as well as alot of other mods.) My car pulls quite hard all the way to redline without any drop off as well. I'm sure there's more power left in the tuning, and upping the boost, but it's plenty fast right now. There's lots of other things to do with tires, suspension, weight reduction, aero etc. etc. that I would change before I decide to do anything with the power of the car.
12-22-05, 04:57 PM
#31
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Originally Posted by lechnoid
I already planned on doing exactly what you suggested with the IC. I'm still debating about porting or not. I know it'll give me more hp, but right now I'm not sure if my budget will be able to handle the stresses of going through ported engines time and again. It's still up in the air.
Other things I'm still considering are:
suspension setup
what wheel and tire sizes that will match up with my needs
fuel system/ecu specifics
Other things I'm still considering are:
suspension setup
what wheel and tire sizes that will match up with my needs
fuel system/ecu specifics
The porting is not nessasary, but its just a nice to have. For your wheels and tires, size depends on what size breakes you want to run. a 17" wheel should safice for most big break packages. I am running 17X9front and 17x10rear ADVAN SA3R's, they are allitle heaver than stock but they work great. For track days i use the stock wheels with ADVAN 245/45WR-16 A048 tires. its really hard to beat the stock wheels with semi-slicks! Tires are peobibly the most important purchass you will make, remember its the only part of you car that comes incontact with the ground. The ADVAN A048 tires are exceptional on the track, for me personally, i wont use anything else.
If you are going to run anything wider that say 10" rims you are going to need a set of coilovers, otherwise the tires will rub on your supenssion. for your suppension, the factory R1 settup is pretty good, however a set of adjustible coilovers would mean that you can run a stiffer setup on the track then lighten it up for the ride home. also, you might want to think about upgrading your swaybars. And most imprtant, your safty, get a rollcage. It will stiffen the chassis but it will more importantly keep you safe! I know a lot of people do not put rollcages in there cars even if they run them on the track, I am one of them, its not safe. I have had some near misses and I will not run on the track again untill i put a cage in.
12-22-05, 05:02 PM
#32
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Originally Posted by lechnoid
I already planned on doing exactly what you suggested with the IC. I'm still debating about porting or not. I know it'll give me more hp, but right now I'm not sure if my budget will be able to handle the stresses of going through ported engines time and again. It's still up in the air.
Other things I'm still considering are:
suspension setup
what wheel and tire sizes that will match up with my needs
fuel system/ecu specifics
Other things I'm still considering are:
suspension setup
what wheel and tire sizes that will match up with my needs
fuel system/ecu specifics
For fuel system, the RotaryExtreme fuel system would fit your needs, and ECU depends on how sure you are about keeping your setup the same. If you are positive you are going to run twins then you can send your comp to PETTIT and have them tuen it for your needs. if you think you will change your setup sometime in the furure, go with the Apex PowerFC. this can be tuned for any changes in your setup. and most important, get it tuned by an expert, like Steve Kan maybe.
12-22-05, 11:13 PM
#33
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Originally Posted by DCrosby
All this is fine and geat..... but these people spouting off 450 HP on an RX6 or any other sigle for track use either are HOPING for such numbers or aren't telling the whole story....
-DC
-DC
450 bhp:
Rotorsports Racing streetported motor
RB aluminum flywheel
Apexi RX-6 turbo w/intake
850cc primaries (I think)
1300cc Secondaries
Apexi Front Mount
Fluidyne Radiator
Fluidyne second oil cooler
No emissions stuff
Greddy pullies
PowerFC
Bonez hi-flow cat
RB dual tip exhaust
upgraded fuel pump
He's running about 15psi on 93 octane
Last edited by quicksilver_rx7; 12-22-05 at 11:32 PM.
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