Circuit (road course) 7m Race engine - More Boost?

[Supra56]

I have a 7m powered Supra Sports Sedan.
I was after some idea's to gain a bit more horsepower?.

Rough spec's
Garrett T04z Turbo
20psi boost
currently makes 538hp at rear wheels.
Forged pistons
cams
custom intake
Head work etc
Water spray onto intercooler
Straight through 4 inch exhaust
running on avgas 100mon rating
Currently using max of 7000rpm

The races the car is in over a weekend, range between 15minutes to 30 minutes long. (3 races in total)
As a result I cannot run the sort of boost a drag car has, as the engine has to run for much longer periods of time, and the heat generated for long periods of time would be a problem.

I am thinking of raising the boost to roughly 23-24psi and running on sunoco turbo fuel 108 ron octane, however I obviously don't want to blow the engine up.

Is it know, if raising the boost to 23-24psi, causes problems with the 7m. After some forum members ideas.
Thanks

 

[te72]

What courses are you running? That might give people a better idea of how they would approach your situation. Depending on the track, more traction or brakes may benefit your lap times more than more power.

 

[IndigoMKII]

What courses are you running? That might give people a better idea of how they would approach your situation. Depending on the track, more traction or brakes may benefit your lap times more than more power.

I'd be more interested in an average speed as opposed to the courses ran, as long as you keep good air flowing it doesn't limit your options as bad.

If you're worried that a few more psi will hurt the engine you could always get a meth injector kit to keep the IAT's down over long periods.

 

[te72]

Water meth would be a good option as well, but for a 15-30 minute race, I would suspect you would want a fairly large tank, depending on how much of it you're using.

What have you done for aero? That can also make quite the difference in corner entry speeds...

 

[Supra56]

I have alot of racing experience, some professional and now mostly as a hobby. Tracks range from Bathurst to smaller ones (most average a speed of 100mph)
The car has alot of aero, undertray, large air splitter, large rear wing, flat bottom, exhaust blown diffuser. The radiator/intercooler have a carbon fibre shroud, and the radiator is as big as can fit.

I am racing against similar cars which have injected nascar engines 800+hp. Most of the tracks the car has more than enough power, just want a bit more down the straights to see of the chev V8's.

We are restricted by various rules and cannot run water meth, I just found on other threats, that people are running up to 23-25psi, I wanted to know if anyone had run one for any length of time, so I could do the same. I appreciate the suggestions and will consider all. Thanks

 

[IndigoMKII]

My only concern with running increased boost for a longer period would be heat soak inside the engine bay. I'd suggest wrapping the turbo cold/hot side in heat wrap along with a t4 turbo blanket.

 

[Supra56]

It has heat wrap. But the turbo does not have a blanket, so I will add this.
Thanks

 

[IndigoMKII]

Have you thought about trying to make custom air dams to route the air exactly where you want it?

Just a thought.

 

[te72]

Have you thought about trying to make custom air dams to route the air exactly where you want it?

Just a thought.

This has been a consideration of mine for a while now, just for the sake of efficiency, but never really gave it much time... Do you have any way of extracting heat from the engine bay? Not sure if it would affect the overall aero, but it might help alleviate some of the additional heat from the increased boost.

Totally inexperienced with this sort of thing (lots of theory, next to no actual experience though), but have you considered coating your intercooler pipes and intake manifold? We do have a few other members on here with some serious seat time (one of your fellow Aussies, John... last name escapes me at the moment), hopefully some of them will chime in, I love reading about this stuff.

 

[Dub537h]

Hood tilt yo!

 

[IndigoMKII]

Hood tilt yo!

Do you mean hood latch spacers? That'll mess with the aero a bit much. Could you 'in theory' create a vacuum from the air going under the car to help evacuate some of the hot air under the hood? I realize air under a car trying to race is kind of counter-productive but still..

Or you could try running ducting through the frame of the car and coming out near the rear fenders? Put a small fan inside the ducting you further aid it but not as to restrict it.

 

[Poodles]

Hood tilt yo!

The base of the windsheild is a high pressure zone. You're effectively hurting your cooling at speed doing it (plus it looks stupid)

 

[Supra56]

The car is basically a fibreglass shell over a tube frame. Picture a nascar, only with a fibreglass shell with big wings etc.
The floor is flat and very close to the ground. The exhaust has to go around the floor to get to the rear diffuser.

I think I am limited with engine bay cooling as Poodles states it is an important area for cooling. The front undertray limits air that could be diverted to around the turbo. Though I might be able to direct some air to assist. It looks like I have to find a way to increase the boost just for the straight, (within the rules). It currently has an adjustable boost dial, which previous owner put in to decrease the boost in the wet. (it dosn't really work) It I can get it to work, I may set the boost up to 23-25 for the straight, and turn the dial down to 20psi for the rest of the lap.

Thanks for the ideas.

 

[mytmk3]

Can I please see pics

 

[IndigoMKII]

The car is basically a fibreglass shell over a tube frame. Picture a nascar, only with a fibreglass shell with big wings etc.
The floor is flat and very close to the ground. The exhaust has to go around the floor to get to the rear diffuser.

I think I am limited with engine bay cooling as Poodles states it is an important area for cooling. The front undertray limits air that could be diverted to around the turbo. Though I might be able to direct some air to assist. It looks like I have to find a way to increase the boost just for the straight, (within the rules). It currently has an adjustable boost dial, which previous owner put in to decrease the boost in the wet. (it dosn't really work) It I can get it to work, I may set the boost up to 23-25 for the straight, and turn the dial down to 20psi for the rest of the lap.

Thanks for the ideas.

You could always setup a high/low switch if you want to do it manually and mount it on the steering wheel like those cool NOS buttons on FnF!

 

[te72]

Can I please see pics

Pretty please?

I was thinking something along the lines of this:
http://flyinmiata.com/index.php?deptid=4544&parentid=0&stocknumber=29-40000

If anyone knows a thing or two about racing, you could say that Flyin Miata does.

 

[Poodles]

Well, I know HKS used to have a "scramble boost" feature on their boost controllers. They even sold a remote button for it (crisp has one).

 

[Supra56]

I have to check the rules, but I believe electronic boost controller's are illegal. Otherwise they would suit perfectly, though a remote controller sounds good, (hidden)should then be enough to see off those V8. Do we know how remote they can be, can someone in pit lane adjust it for me if I am busy trying to overtake etc.
.
Pictures: I will post in a few weeks time.

 

[IndigoMKII]

I don't think they're quite THAT remote.. I think he was meaning to like hiding it on under your seat or something..

I'm not entirely sure they're even 'remote' but still wire connected.

 

[7MGTEsup]

Well, I know HKS used to have a "scramble boost" feature on their boost controllers. They even sold a remote button for it (crisp has one).

My gizzmo EBC has this function and you can set the time duration on it and if you press the button more than once it adds another dose of duty cycle ontop of what you already added.

So if you had your base boost at 20 psi you could set it so one push gave you 23psi and a second push gave you 26psi