23Racer

I have spoken about my car a number of times, so I thought that it would be good for you guys to see what the car looks like. I have included a couple of shots underhood so that you can see that it really has a 4 throat ITB setup, LOL.

Eric

peejay

What are you running for an exhaust?

Just curious. I'm thinking of just patterning next year's setup after yours, since yours seems to work so well for you.

j9fd3s

iTrader: (3)

car looks great! i think i remember a build thread or something, so its not new, but a nice refresher....

oh BTW i'm thinking about copying the paint, cause its obviously working really well for you. car is turbo though....

23Racer

The car is definitely not new! I started racing it in 97 and it has gone through a constant evolution since then. This is the latest version and I believe it is the fastest version. I will find out the 17th weekend.

I just wanted to post shots of the car again so that people could see the 4 throat ITB setup and how it fits into the engine compartment.

Eric

23Racer

I am running a Racing Beat race header extended out into two 2" exhausts that collect through a merge collector into a single 3" exhaust. Two 90 degree elbows into a 3" internal Race Borla then out through a megaphone outlet.

I don't know, but it works very well in this car.

Eric

diabolical1

iTrader: (3)

nice. real nice. i really like the whole car!

TWM throttles? what manifold?

23Racer

They are Hayabusa 50 mm bodies and the intake was made by ourselves. We did some studying on intake lengths and power peaks and determined that as we wanted an approx. 8,000 rpm peak, I needed an intake length of approximately 14". I have never been able to determine where the measurements are from, but I guessed at 14" from the keg face to the opening of the intake trumpet. I guess that I was right as the car just works like a champ and is extremely flexible. I expect that it could be fine tuned, but with the porting in the engine and the intake runner lengths and diameters (different between primary and secondary), I may have stumbled upon something that works well enough for me.

Eric

fidelity101

iTrader: (11)

I like everything but that strange coolant pipe for the radiator to block setup.

Laxfreak3557

Do you have any pictures of this? Sounds interesting. How is the noise?

23Racer

I don't have any pictures, but I will try yo post some next week. The exhaust is a simple as can be. The header connects to 2 2" pipes that extend back to just past the front crossbrace on the rewar subframe. The 2x2" to single 3" merge collector tucks alongside the diff and the 2 90 degree 3" elbows move the exhaust over to about where the stock passenger side muffler is, then you add the Borla with a 12 " megaphone that expands to just over 5" at the outlet.

It is freakin' loud and not stretable at all. If I run at a track that has sound limits, I replace the megaphone with a plated Super Trapp.

Eric

diabolical1

iTrader: (3)

dude, that's great. i only hope my neanderthal understanding of intake/exhaust length tuning leads me to the same result you have seen. kudos on the work with the manifold. i like it.

i keep checking ebay every once in a while for motorcycle throttles in my price range, but so far i have not found any. maybe i'm not being realistic. however, i do have some 50 mm TWMs that i will be using for mine.


actually, that's one of the things i like the most in his engine bay.

fidelity101

iTrader: (11)

I can see how the increased cooling capacity and heat dissipation would work nice but it reminds of my old s chassis days where people would swap in SR20s and keep the stock KA radiator and have a goofy time connecting the inlet/outlet pipes because the radiators were reversed essentially.

23Racer

The Rad is a basic Howe rad for small block Chevy's. It fit in reasonably well and the lower rad hose was the same diameter as the RX7 one. It actually uses a stock lower FC hose. The only problem was that the upper was on the opposite side and a different diameter. The cross over allowed me to reduce the diameter and locate the hose properly going in to the upper keg inlet.

It works well and is reliable. The rad can handle up to 500 hp and the whole thing cost me under $200. I can also get a replacement rad in about 30 minutes as it is a standard stock car piece. No issues, cheap and easy, I didn't see anything wrong with that.

Eric

23Racer

For those who are interested, here is a closeup of the intake as shot from above.

Eric

Shainiac

iTrader: (7)

Why not just run the primary injectors in the TBs and ditch the stock ones?

23Racer

Ding, ding, ding, ding, ding, we have a winner!

In the 4 years that I have run this setup, I finally have had a question about this. Somebody noticed, LOL. We initially had all 4 injectors in the throttle bodies. When we were trying to tune the car we always had a lean hole around 4,500 rpm. This is just after the Megasquirt starts to really use the secondary injectors as a fueling source. We tried richening the mixtures independently and together changing pressures etc... Nothing worked. I finally, in desperation, put the stock primary rail back together and immediately everything started working better. I have not changed things again since then as it works and is durable. I think that it may have something to do with the pressure pulses in the primary tubes at approx 4500 rpm. We could see fuel being sprayed back out of the primary intake bells at that rpm.

It also gave me the opportunity to draw a vacuum off of the injector hole so that I could go back to power brakes, which make the car far easier to drive.

Eric

fidelity101

iTrader: (11)

ahh that makes sense, well i can't argue with cost and performance effective lol.

Hell I run audi A6 fans I got from the junkyard, biggest dual fan shroud covers just over the whole radiator and it was about 30 bucks.

Shainiac

iTrader: (7)

Bizarre. Did you ever try running the injection not in the typical primary/secondary, but all together? You're running a bridge on the secondaries and a street ported primary? I am building a peripheral port motor and running RC51 motorcycle ITBs (2x54-62mm) with 4 injectors, but I am starting to think it might be easier to just buy two ID2000s and run one per rotor!

23Racer

We did when we first converted to Alpha N control. It worked very well, but the fuel usage was really poor. We couldn't make an hour on a tank of fuel. We converted to staged and now we can go to 75-80 minutes on a tank. As well all 4 injectors operate at the same time above 4,500 rpm, its just at lower rpms that they are only running on the primaries.

The other thing to recognize is that the primary runners are almost a .25" smaller in diameter as compared to the secondaries. They also have a slight turn right out of the throttle bodies. All of these may be contributing factors.

I would think that in a peri port, that as long as the injectors are firing at the same time, it wouldn't matter how many you had in the runner. You may also want to run 4 injectors as you can stage the firing like we did and get better low speed atomization and therebye better throttle response and fuel economy. Having a big injector barely operating at the low end of its duty cycle, may not be the most efficient.

Eric

j9fd3s

iTrader: (3)

2x1000cc injectors will be more than enough! you could even run 2x700. the PP engines have a better BSFC than the side ports. you'll see when you get it up and running, it won't want a lot of fuel

ivegonemad

I LOVE THIS SET UP!!! i would love to see the ITB's standing upward rather sideways....but this is the first 4 throat ive seen.... nice nice nice!

btw video now! ahahah i wanna hear this....

23Racer

They are actually at around a 40 degree angle from horizontal. It was the only way I could get them to fit with enough airflow to the bells.

Eric

23Racer

Shot from the back to show the exhaust outlet. It is 5" at the tip, so the end pipe grows from 3" to 5" over a stretch of about 12". I had some rear fascia melting until we got the fueling under control and now we only get slight exhaust cough flames on shifts and overrun.

Eric