Who has played with a rising-rate regulator or adding a switch to a cold start valve to be used as a 5th injector to get a little extra pony power?
Here's one...
MicroDynamics RisingRate Regulators are designed for use with all types of fuel injection systems. Added to standard systems they increase the mixture range for high performance or provide "boost or load enrichment" on both turbo and naturally aspirated engines. Rising-Rate will also give more fuel at the top end without going over-rich lower down the rev/power range.

A MicroDynamics RisingRate Regulator is often the only form of fuel enrichment required for many retrofit turbo conversions and is usually the easiest way to obtain increased fuelling on production injected race vehicles.

Here's one by Bell Engineering $179

Here is an interesting article how to make your own rising-rate pressure regulator from a stock 914 regulator

Funny, I was just thinking about this today. Wonder if you could use the ported adjuster from a decel valve to do the same thing instead of the mod described? The decel valve and the FPR are very similar in construction.

I have popping issues while under boost and cold on my Type I motor.....hmm, this looks interesting.

Didnt the 1.8s have a manifold referenced fuel pressure regulator? Most modern cars have a manifold referenced regulator. It is a bit amazing that the d-jet cars didnt have one. Since the d-jet cars didnt have one, adding one would probably make it run worse, since they have already compensated for the differences in flow between open and closed throttle.

Z,

Are you running cards or FI?

Cause if you are running a carb (or carbs)

Unless you have a blow through setup.

I don't see how a rising rate fuel regulator will help you.

I can see a 5th injector helping you... if you need one.

Conversely, if you have a draw through carb. A rising rate won't really help you. As the carb never see the boost signal.

And have you dyno'd that engine yet????

I have some more mindless questions coming later....

C

Dual throttle bodies.....we got 160hp with 5lbs of boost.

I put a heavier (10lbs) spring in but I am either losing pressure thru the BOV or the seals on top of the throttle bodies.

We did the dyno, the exhaust got white hot....

What were the EGTs when the exhaust was white hot????


C

1450F

Well, that would be awfully nice if you could get more air into the engine to go with that fuel. Otherwise, you're just richening up the mixture, most likely to the point where you get worse power and beyond that.

The only people I know of who did the RRFPR thing and seemed to have it work OK were running boost. Jeff Shyu (Jenny's brother) did that on his D-jet turbo 914. (Yeah, I know--you can't turbo a 914!) Otherwise, it's just a way to richen the mixture with higher throttle settings in a way that is diffcult to reconcile with the way the stock D-jet is working.

The L-jet FPR used on the 1.8 is supposed to keep the fuel pressure at a constant difference from the manifold air pressure, so you get a consistent amount of fuel going in for a given injector opening time. It's one way to remove one of the variables that occurs within the intake system, and probably the most useful when you are designing and/or programming the EFI system.

--DD

Uhhhhh.... No wonder the headers were white....

I B surprised the engine didn't take a shit on you.

Is this the MS brained engine?

Even better... Do you have pics and a build sheet for induction, spark, turbo, brain, complete fuel system setup, etc....

Cause that thang needs a fixin...................

This way we can hijack the entire thread... Just like the good old days......

C

ive heard good things....

What things have you heard AA?

C'mon... people want to know...

Are the voices getting clearer???

Do you know where they are coming from.....????????????

Yep - that's the one. It does run MS-II with an LS-1 wideband O2 sensor. It has a raising rate fuel pressure regulator sensing manifold pressure. However, I think we are running too lean under boost. I need to get the laptop hooked up again to read the wideband data while under boost...

Last time we had to sort out timing since we got some pinging under boost. The MS-II software is sort of buggy. Often doesn't remember changes to the 12x12 tables and reverts back to an older setting. This makes tuning cumbersome but it needs more work....