787Blover

im trying to build a circuit car around 500-600hp. i was wondering if anyone has a car set up to around that much power. i am trying to figure out weather i should go with single or twin turbo, and wat kind of seals ill be needing. ive got the suspension and most of the stuff ill be needing figured out i just wanna get some advice about wat turbo set up and wat kind of computer need for it.

23Racer

Put an LS1 in an FD. 500 HP easy with simple maintainence. I am not trying to be a pr!ck but a 500 hp rotary might be too difficult to maintain for somebody who needs to ask these types of questions. Just working out the support systems requires a ton of experience and knowledge.

A 500 HP drag car is a lot easier to run as the engine only has to run for at most 30 secondsd. A circuit car needs robust cooling systems, fuel systems, electrical systems, gearboxes and rear ends. This is assuming that the suspension and brakes can live up to the task.

My suggestion is have somebody build you a real 250 - 275 hp NA BP plug it into your car and start working on the lower stress systems.

Regards,

Eric

RacerJason

iTrader: (5)

Have a death wish or do you think you're that good a driver already?

20B-3Rotor

What kind of car?

like jason said are you crazy....

We have 335's ra-1 on our race car and thats a handful to drive.... unless you looking for stright line power and than taking it easy in the corners

R.P.M.

iTrader: (3)

Alot of $$$$

13B Cosmo RE engine block
Monster Streetport
Long tube header
GT35R turbo
Big fuel system
Wolf V500 EMS

Done deal 500whp min garenteed.

Nismo Convert86

iTrader: (7)

You don't need a Monster streetport for 500hp, stock size s5 Tii ports in that configuration have made 770whp. They used a Precision Turbo, and not a Garrett.

nik

GT35R won't make that kind of power on a 2 rotor, you need bigger.

This is a pretty tall order, you'll need an transmission upgrade as well unless you want to keep breaking them.

Can saf probably has the closest thing to that right now, via 3 rotor P-port. What's the purpose of the car?

R.P.M.

iTrader: (3)

Cool!

A streetport would help flow more air and spool the turbo better putting less stress on the engine. Also the Garrett GT35R's are so cheap now that they are almost a throw away turbo. Ball Bearing is what you'd want for almost instant spool when coming out of corners.

The 35R along with a big streetport would be perfect for circuit racing, next to no turbo lag

R.P.M.

iTrader: (3)

No. Dia. Trim System
GT-35R 82mm 56 Ball Bearing Rated for 680HP

Hey Nik, aren't you guys using a 35R? What power are you making?

nik

Yeah that's for a piston engine, and for that it is accurate. For rotary it depends on the hotside. The T3 is just too small. It's good for about 400 whp +- dyno accuracy around the usual boost levels (15-17psi). But that's a big ballpark figure.

We had 375 on the dynapack when steve kan tuned it, and seen as low as 320 on a mustang dyno which was misreading rpm(on the same tune). That's with an off the shelf gt35r with t3 1.06 turbine, and essentially no exhaust. This year we have a T04z.

The GT35R is a good turbo for circuit racing, it has good spool and good power. If someone is saying they need 600 HP in a circuit race car, they are either dreaming or running a pretty serious series.

FC3S.USD

iTrader: (2)

finally to4z TIME ! , got pics or updates anything ?

B6T

iTrader: (2)

No doubt porting helps spool the turbo, but how does lower power output and a more gradual increase in power from a laggier turbo result in lower stress on the engine? Or do you mean thermal stress?

2Fierce

iTrader: (7)

supraforums

/thread

Alak

iTrader: (9)

Hes talking about how the engine has to work less to create the same amount of power. The Porting helps the motor flow better and produce better power, not nessesarily more.

B6T

iTrader: (2)

So I guess he's basically saying that the larger ports will reduce pumping losses, which in turn reduces the stress on the engine?

eViLRotor

iTrader: (2)

Azad, it looks like a turbo

Saw it this weekend, and with the new manifold, it sits much further forward than the GT35R.

500whp is definitely possible with the GT35, but 600 not so much. I used to look at a lot of GT35 dyno graphs, when that turbo was en vogue, and never saw anything like that. At those power levels and up, it seems like the GT42 is the turbo of choice from the Garrett Line.

The GT35R is a great street and lapping-day turbo, because it has super quick spool. If I remember correctly, the race car was making serious boost (12psi) by 3000 rpm.
But, for racing, it might be a bit small, since you don't need the low rpm, and it was starting to fade up high. Hence, going to a bigger T04Z.

23Racer

I think it is interesting that we are discussing how to make the 500 hp target. I know that it can be done and using not exotic equipment. What I am always concerned about is making 500 hp in a turbo car reliably. This means all of the support systems.

For example, to get the flow what size intercooler would he need? A large intercooler blocks off most of the rad and this results in skillful determining of rad size, airflow through the rad and after the rad. What oilcooler would he need? Where would he place it to not block off airflow and still get enough airflow to the oil cooler. To put that much power through a gearbox, any stock cased Mazda box will be on the limits of its capability to handle the power. How do you cool the gearbox and diff fluid? Look at all the issues the Can Saf car has with the stock box. They are using a 3 rotor which has similar power characteristics, with lower torque levels (I may be wrong about the expected torque from a 500 hp Turbo).

How about the fuel system? A 500 hp car would require at least a 22 gallon cell to make it through a race. You have to fab the install and the lines, to and from, the surge tanks, pressure regulators, etc.... That is a ton of work to make it reliable and also able to supply 500 hp.

All of these issues dont even consider the requirements of the braking system, suspension and chassis rigidity/ cage to safely handle that kind of power.

For a drag car you can just build an engine and fuel it and go well. For a circuit car there are a ton of other systems that need to be worked on to make a car that is reliable and fast.

That is why I find this to be a moot discussion. If the thread starter has to ask on the forum how to build a 500 hp car, I am concerned that the knowledge exists to build all of the support systems to make it work reliably. Both Al and I have gone through years of adding cooling and more fuel to build high 270 - 320 hp rotaries and I know from a lot of experience, how difficult it can be to build a 500+ HP car by being involved with the Cobra R project out in Vancouver.

Eric

Redshft

iTrader: (1)

Would you actually HAVE to go turbo? If you are spending that much money anyway...
The SpeedSource RX8s (for example) in Grand-Am are aprox 450hp. (3-rotor pp) Not sure if there is more to be had in there (are they limited by class rules?) or if they are at the limit of what the engine will do.
Or, if you really want to spend a bucket of money, you could build a 4-rotor. Replicate your name-sake 787B. Huge money, put probably not much more than building a reliable turbo circuit car.

If you built the car NA, you wouldn't have to worry as much about cooling (no Intercooler blocking the rad, no Turbo's to cool etc.) plus it probably wouldn't have as much torque, so you might not need to overbuild the gearbox etc.

Even the 3-rotor PP at 450ish hp, while slightly below your power goal, would probably be just as fast on a circuit since you wouldn't have the weight of the turbos, intercooler, upgraded components etc.

Also, can I ask how you arrived at this power goal? Going from memory, the 787B was 650hp in LeMans tune, and the SpeedSource cars are around 450hp. Who are you planning to compete with?

R.P.M.

iTrader: (3)

https://www.rx7club.com/single-turbo-rx-7s-23/maxed-out-gt35r-t3-dyno-746924/

511whp @24psi on a T3 GT35R

R.P.M.

iTrader: (3)

Both thermal stress (which is bad) and as Alak said it doesn't have to work quite as hard to produce the same power, therfore less stress on the engine.

nik

I'm not gonna start arguing dyno numbers because those things are so variable. If you read the linked thread about the 511whp you'll see what I mean. Also 24 psi on that turbo is pushing the envelope of turbo reliability. We've trashed a few of these at regular boost levels in racing conditions. The GT35R is an adequate turbo for circuit racing. In my opinion the hotside is too small for a rotary, especially in road racing. The T3 turbine inlet flange has a comparable cross section area to a stock turbo 2 inlet.

Addressing the intercooler and oil cooler issues is not as hard as you might think. Intercooler is V mount and either upgraded oil coolers(oil to air) and/or oil to water coolers. Fuel consumption will be very high.

R.P.M.

iTrader: (3)

Your right, there are many variables and yes 511whp is pushing the turbo to its limit. But you can get a T4 hotside to work on a 35R.

As Nik said, a PWR liquid to air I/C would shorten the I/C piping and wouldn't block as much air to the rad due to its smaller/thinner rad it uses.

nik

Yeah the T4 hotsides are a better option, althought I think your selection is still pretty limited. I think they are available from ATP turbo.

However, I stick to my original position that it's a bad ideato use GT35R if those are seriously the power goals. It's always bad policy in racing to push a part near or past it's maximum design parameters.

I am pretty convinced that a V mount intercooler (air to air) is the optimal setup for circuit racing. I haven't heard of many trials with air to water, but I can think of immediate weigh and complexity disadvantages. I'll probably be trying it on my car this summer(not the race car), and then i'll have an opinion on that too.

CrackHeadMel

iTrader: (2)

i dont think the benifit of an air to watersetp is really there in a circut car. the water is nice in a drag car becase you can pack it with ice, and it only has to last afew min from staging to the end of the track

a circut car has to run for much longer, in esence your are just adding an uncesseary step in cooling charge air

Black91n/a

This is totally *** backwards. That's the wrong way to go about building a race car.

What you should be looking at, instead of an arbitrary power goal, have a lap time goal and look at what sort of suspension, brakes, wheels and tires, and power that'll require. Look at what times the local racers are getting and see if you can find out a bit about their setups. 500hp will be useless if you can't put it to the ground, cool it, stop it or get it around the corners. There's WAY more to a race car than power. Also, 500hp is A LOT different in a 2000lb car than a 3000lb one.

Starting out with some arbitrary goal like 500hp is a good way to end up with a powerful, slow, handfull of a car.