Another S/C'd member worried about his AFR

[LtNoogie]

Ok, I just spent a half hour on the phone with dyno guy. He does not recommend that I start with larger injectors or more powerful fuel pump. He recommends a boost-sensitive adjustable fuel pressure regulator.

He also states that his expertise is with muscle cars and not ligament cars. (my words )

Hey, we have enough Blitz'd owners on this forum now that each of us should try one tuning method and report back. And then we slowly go from there!

I hear crickets chirping.

[kurokoma-kun]

Originally Posted by LtNoogie

I hear crickets chirping.

Ok well, here are my thoughts.

I'm not convinced that injector volume is the issue... the stockers are rated at 210cc? (someone please correct me if that's wrong) which should be good for 130 hp. But I'm no expert and I guess there's only one real way to find out, so I'll be very interested to see anyone's results with larger injectors (fuel pump, pressure regulator, etc).

The main issue for me is that I have neither the funds, time, access to professional tuning, nor personal interest enough to justify f***ing with the fuel system, at least not right now. Reason 1: the "plug + play" nature of the Blitz kit was one of the primary reasons for it's appeal to me, and I'd kinda like to just race and enjoy the car as-is for a few months. Reason 2: if I was gonna go to that much trouble I've have gone turbo, where the money and effort invested in tuning promises much greater payoff.

Now, a relatively simple mechanical upgrade intrigues me a great deal, which is why I've expressed interest in using my car as the guinea pig for the pulleys NST has said they are willing to develop (overdrive crank + u/d w/p). From what I can gather this set up should also help with any belt slip issues. The question of whether the fuel system can keep up with the increased boost produced has been raised--if it can't, then frankly I might abandon the project at that point... so maybe one of you interested in altering your fuel system woudl be a better candidate... if you think so, you might want to talk to Garm or Mike at NST about it.

[LtNoogie]

Originally Posted by LtNoogie

Ok, I just spent a half hour on the phone with dyno guy. He does not recommend that I start with larger injectors or more powerful fuel pump. He recommends a boost-sensitive adjustable fuel pressure regulator.

Thanks to CTScott, I found the OEM fuel pressure regulator. It is not in a place that is easily replaced by an aftermarket unit. Since the fuel system's pressure is now maxed out at the 44.1 to 49.7 psi put out by the OEM regulator, using another regulator after this unit to get higher pressure is impossible.

Dyno guy now admits that replacement of the fuel pump (like Garm's turbo install) or replacement of the stock injectors is probably in order if the goal is to get more fuel to the engine during boost.

Calculating the proper injectors size, using the many online injector calculators, is a little bit daunting but I'll use them all until I can understand the concept and get consistent results.

I'd rather understand the science behind the proper selection of injectors rather than just shotgunning any device in and hoping that they do the job adequately.

[largeorangefont]

Originally Posted by LtNoogie

Thanks to CTScott, I found the OEM fuel pressure regulator. It is not in a place that is easily replaced by an aftermarket unit. Since the fuel system's pressure is now maxed out at the 44.1 to 49.7 psi put out by the OEM regulator, using another regulator after this unit to get higher pressure is impossible.

Dyno guy now admits that replacement of the fuel pump (like Garm's turbo install) or replacement of the stock injectors is probably in order if the goal is to get more fuel to the engine during boost.

Calculating the proper injectors size, using the many online injector calculators, is a little bit daunting but I'll use them all until I can understand the concept and get consistent results.

I'd rather understand the science behind the proper selection of injectors rather than just shotgunning any device in and hoping that they do the job adequately.

If that is truly the problem, you could try a boost-a-pump. You need a scan gauge or tool that can tell you injector duty cycle to know for sure if you need anything.

You guys will not be able to solve this by just swapping out parts. You will solve one problem and create 5 more with bigger injectors.

[LtNoogie]

Originally Posted by largeorangefont

If that is truly the problem, you could try a boost-a-pump. You need a scan gauge or tool that can tell you injector duty cycle to know for sure if you need anything.

You guys will not be able to solve this by just swapping out parts. You will solve one problem and create 5 more with bigger injectors.

What is a boost-a-pump? Can you post a link to a comparable product online? I have not seen injector duty cycle as available for display on the ScanGauge. I am guessing that some instrumentation would have to be connected to the injector wires to measure duty cycle? This intrument would have to be sturdy enough to measure during WOT?

[TOUGEghost]

Originally Posted by LtNoogie

What is a boost-a-pump? Can you post a link to a comparable product online?

Here's the link:

http://store.summitracing.com/partde...5&autoview=sku

It increases voltage to the fuel pump as boost increases. Seems like it could be a good solution for moderate boost levels.

[LtNoogie]

Originally Posted by TOUGEghost

Here's the link:

http://store.summitracing.com/partde...5&autoview=sku

It increases voltage to the fuel pump as boost increases. Seems like it could be a good solution for moderate boost levels.

Thanks, I had seen that earlier. My thought is that a properly working fuel pressure regulator will hold the current pressure unless it fails. My water pressure regulator at the inlet to my home maintains a constant 80psi across a wide band of street pressure.

Any mechanical engineers out there?

[dallas]

Ive seen the Boost-a-pump used on a buddys Mustang and it works well, if you need to squeeze a bit more out of the fuel pump. If Richard Holdners Intake /exhaust combo made more hp than the supercharger it must be using more fuel to acheive this. I don't think it's the fuel delivery, but maybe the management of the delivery thats causing a lean condition. I wish you pioneers luck to figure this out.