coldfuzion76

That last video is really sweet. &*^*&^((*&^@! I'm never going to have a running car if I keep finding stuff I want to do to it!

coldfuzion76

Just throwing an idea out there, but have you considered switching to the turbo manifold to straighten out the air path now that the AFM is out of the way? Not sure it would even be worth the effort power-wise, but it might clean things up a little bit. I've deleted my flip up headlights, so I was thinking about running the intake into the nose like the V8 guys do sometimes.

V2Rocket

A WHILE back someone did a dyno test back to back with the na/turbo manifolds with the afm still installed and it was good for ~4-5 hp at the high end.

ill get around to testing it with the maf eventually.

odonnell

It would be interesting for sure. I wonder if the same gains could be found by extrude honing the NA manifold...it's not exactly smooth in there. Another option is ITBs, which would definitely help. The speed density tuning algorithm looks at MAP, IAT, and TPS so it's definitely feasible unlike any setup involving an AFM or a basic MAF. That would be a cool project...

V2Rocket

extrude hone doesnt do anything except lighten your wallet by $500+.

its to get a certain surface finish on aircraft parts, it doesn't do anything for airflow

coldfuzion76

A while back I read on a thread where a guy was trying to use ITB's, and had a problem using the MAP due to an uneven vacuum signal. I think he wound up Using Alpha-N. Nothing the 'squirt can't handle, though. and Busa throttle bodies are CHEAP for what they are.

Dougs951S

the MS2Extra code that michael and I run is also capable of running blended alpha -N which is possibly a smoother choice for an ITB setup. The throttle linkage is also an important part of the puzzle, it has to be fairly progressive and slow opening with respect to pedal input at low openings. For those who dont know, the real issue is that when opening the throttles from idle or from low loads, ITB's can be touchy and hard to control, and also have a tendency to bog if opened too rapidly. I have a set of ZX12R 46mm throttles on my desk. I originally intended for them to find their way onto my 951, but they are more likely going to end up on my NA instead. They're a little oversized for that application, but we'll see. As far as the uneven MAP signal is concerned, this is easily solvable by simply using a vacuum manifold to draw the signal from, which sort of helps to "average out" the signal by drawing from a larger collective manifold rather than from behind each throttle. I am going to reuse the kawasaki TPS if I go this route, its a compact, reliable unit of the proper variable potentiometer type and should work great. My plan for a manifold is a hacked up NA unit, flow bench testing has shown the NA runners to be superior in flow and also more even runner to runner vs the 951 intake. The turbo intake manifold was somewhat of a packaging compromise with respect to the compressor. I'll hack the stock runners a few inches after they turn up and then weld them to the ITB's with some velocity stacks. Add 4 filters, a vacuum manifold collecting signal from each cylinder, and done. Nice thing too is the ZX12 ITB's I have include the fuel rail, the fuel lines, and the injectors. Megasquirt is capable of running two sets of up to 4 high impedance injectors in batch fire mode, letting you run staged injection if you wanted to say, idle on the stock bike injectors for a smoother idle, and then transition to the 944 injectors after a certain load. Endless possibilities.

Noahs944

... just watched this vid. I CANNOT BELIEVE how incredibly smoooooth it is. My car is the complete opposite. Do you still have the Idle Air Solenoid?

Q: why would the DME never allow the engine to idle this well?

odonnell

Yes, it retains the original air valve. It's really a timed throttle bypass on the early cars, it gets 12v and slowly closes over the span of a few minutes. In the vid it would have been fully closed because it's up to temp.

The DME couldn't idle it as well because of a combination of things... AFM squeezing its neck, batch fire (this is semi sequential), less precise spark timing, plus other factors I'm probably not even aware of. The bottom line is that even 5 minutes of tuning will achieve a better idle than the DME as long as your hardware is in order.

odonnell

Passed state inspection!

Well, in TX it's just a safety inspection for cars 25+ years old. But it's the furthest I've driven on the MS setup because the place is quite a drive (not a lot of places in my area are able to inspect older cars, I think it's a licensing thing from the state). It didn't miss a beat, even with 102 deg. heat outside.

Dougs951S

Awesome. fyi Graves on vallry mills always passed my car...i used to drive all the way down from denton to pass the 951.every year.

JacRyann

Great work! How did you implement the idle valve? Tied the closing side permanently to ground? Or used the inverter circuit to generate the complementary signal for true PWM?

odonnell

The early "ICV" is just a throttle bypass that slowly closes as the engine warms up. It has an internal heater element- in the stock configuration, it gets 12v via the fuel injector power wire and grounds through the harness. In my configuration it gets 12v from the fuse panel I made and is grounded through the ground point by the driver side headlight.

I actually really like this setup relative to the PWM idle valve of the late cars, entirely because it requires zero configuration.

odonnell

Doug I used to drive past that place every day when I lived in waco lol

AdrianL

awesome work!!