Exhaust is going to be modified further, but I really like this torque curve.

 

did you try a little shorter header? I would also ask about intake but you are running stock, the intake is the next thing I would do as it looks as there is still some power missing. You should be able to pick up some of that top end with out hurting that beautiful torque curve.

 

I'd think shorter headers would extend the powerband up, not down.

Competition is in the 3000-6000rpm range. I don't care for anything higher than that. If it's over 6000, it's because there's no grip. Making less power at the top end is actually beneficial because then I don't have to waste brain cells on modulating the throttle. The goal is to be able to keep my head outside the car, so to speak.

There is more power to be had at top because it runs a little rich up there, and my ignition timing is quite conservative - it's only 20 degrees and I put one of the advance springs back in to help driving it around town.

I'd like to play with a more proper expansion chamber, but there's just not enough room under the car.

But, jeez... good headers and an IDA intake, I'd be looking at $1500, which could buy me a used Neon which would be faster out of the box.

 

maybe make the header an inch or two longer?

 

Nowhere to easily do that, either

When I say "modify the exhaust", I mean take the straight through muffler off of the thing and install a baffled muffler, suitably reinforced to keep it from exploding. It's okay to drive for a half hour and at 55mph the exhaust is barely audible compared to all of the other noise the car makes but at 70mph it's a full on aural assault, and quite frankly I'm too old for this ****.

I do fully intend to measure exhaist backpressure at idle - 55mph - 70mph before and after.

 

we put a baffled muffler on the race car once, and it did muffle, but it just wasn't made of thick enough stuff to handle the nuclear blast we were throwing at it. you can rebuild, but after every drive? the case of the thing couldn't handle it.

 

j9 do you remember which type of baffled muffler you used? If so I may be able to fabricate one out of either SS or thick mild steel based on that basic design.

 

great for Lasse !
could you please show the dyno sheet ?

 

crazy on seeing the restrictions on manifold design (or other factors that play in) but my S4 street port w/ turbo housings made 185whp@6800-7300 and 152tq @5700rpm. I wonder if the long *** S4 NA intake manifold helped the torque #'s. I think I should also re-dyno my car now that I have injectors to properly feed the engine past 7k and see what happen when the a/f's stay below 14.5:1

 

lmao, all these years later and i still havent dynoed mine... judging by what it hangs with down the main straight i'm putting down about 180rwhp@6000rpm. fuel mileage is way better than a 6 port 13B

 

yeah its efficent on my wallet.

I went carb because I'm cheap.

oh and lazy, which is why I went rotary, I hate doing timing belts and timing changes and piston rings and valve springs etc, too much ****


and how did I make more power than you pete, mine was 132whp and 121wtq

tq peaks at 4700 and hp at 6300

 

That dyno sheet was from the half bridge T2 engine.

The new engine... it's nice. The RB long primary exhaust does not restrict a bridge port very much, and the Holley intake manifold is "freaking awesome" and suffers zero loss of low end.

The SAD thing is, the powerband feels like what they were saying about the IPRA engines with the fancy intake manifolds. It pulls extremely strong from low down, and then at 7500 ir feels like it starts pulling REALLY HARD. And that's where I'm out of injector. That's why it's sad.

 

out of injector is a fixable problem...

 

okay I was gonna say...

but still.

Here was my 6pt streetport carb on a failing alternator stock dizzy 1st gen setup:



wat temp was 205-210
eng comp is roughly 97psi on both rotors