Another S/C'd member worried about his AFR

[Nexus1155]

well holy crap if that the case, are you maxxing out the stock ones? any way to tell? I mean anything over what? 85% efficiency is bad you want it from atleast 65% to be running somewhat safe?

But see this is the problem, you have no way to scaled the injectors constant and must calculate this pretty good based on the amount of fuel it will be dumping in there....Larger injector + same constant = stays open for a longer time = more fuel = richer afr.... good luck

On a GT28 1.8T A4 I was tuning it started out with 210 or 280cc depending on the fpr with an afr of 11-12 while driving, swapped in the 550cc knocked us down to around 8.5-9.0 before i properly calculated the scalar to bring it back up. just to give you a headsup.

[LtNoogie]

That's why I'm leaving this to a professional tuner. I'd end up with stacks of different size injectors and totally frustrated.

[turboecho2005]

Megasquirt is a viable option! it can be done... and it has been done....

I am running it in my car. Its not overly complicated either if you have a little bit of electronics background. I have helped to install and tune with megasquirt before.

Any shop should be able to make you a wiring harness.

[Nexus1155]

I am running it in my car. Its not overly complicated either if you have a little bit of electronics background. I have helped to install and tune with megasquirt before.

I don't know if they have a standalone and a plug in play but ive only seen standalone, but im sure you can wire it in tandem.

did you install it on a yaris or an echo?

[turboecho2005]

Originally Posted by Nexus1155

I don't know if they have a standalone and a plug in play but ive only seen standalone, but im sure you can wire it in tandem.

did you install it on a yaris or an echo?

Megasquirt can be used both as a standalone or a piggyback but its not plug and play.

It was used as a piggyback in my echo when i still has the 1nzfe motor. Timing was still controlled via the stock ecu. The megasquirt took care of fuel.

There was an issue trying to control the VVTi (this was back in 2006) but i am sure someone has figured it out by now. However controlling VVT on the blacktop motor wasn't an issue.

[HTM Yaris]

I think you peeps are looking in the wrong place . I bet if you put your stock exhaust back on you will find your HP and torque . Remember that thing called "back pressure" . You peeps have opened your exhaust too much , IMO .
Opening an exhaust too much will result in a loss of HP and torque . Either you need more airflow to fit your exhaust or you need to downsize your exhaust to create the proper back pressure .

Want proof ? Just check out Noogie vs Poop setup . Poop has the larger exhaust and lower numbers .......

[LtNoogie]

Originally Posted by HTM Yaris

Want proof ? Just check out Noogie vs Poop setup . Poop has the larger exhaust and lower numbers .......

Ooo... don't remind him of that more that three more times!

[PETERPOOP]

Originally Posted by HTM Yaris

I think you peeps are looking in the wrong place . I bet if you put your stock exhaust back on you will find your HP and torque . Remember that thing called "back pressure" . You peeps have opened your exhaust too much , IMO .
Opening an exhaust too much will result in a loss of HP and torque . Either you need more airflow to fit your exhaust or you need to downsize your exhaust to create the proper back pressure .

Want proof ? Just check out Noogie vs Poop setup . Poop has the larger exhaust and lower numbers .......

I think you are wrong. You also forgot that my dyno run didn't go to 6500 RPMs like noogie's. You can see in my chart that the HP was still rising at a strong rate. It stopped at 6200 RPMs. Also, I was on a dynapack, not dynojet. Dynos are different.

I am going to dyno on a dynojet soon, run it to 6500rpms, and I can guarantee you it will be higher than 117hp on the dynojet.

I do agree that my larger exhaust lost torque, but HP, especially in the higher RPMs, naw.

But I am going to be running a 2" 24" resonator and a hi flow cat soon, so that will probably bring me some back pressure/torque back.

[dallas]

I agree that a smaller pipe diameter may help, like 2 inches, but your terminology is wrong. Backpressure is never a good thing, you do not want back pressure for ultimate horspower. What you want is no back pressure but fast exhaust gas velocity, if you go too big on the pipe diameter you loose the exhast gas velocity and the coresponding hp and torque.

Originally Posted by HTM Yaris

I think you peeps are looking in the wrong place . I bet if you put your stock exhaust back on you will find your HP and torque . Remember that thing called "back pressure" . You peeps have opened your exhaust too much , IMO .
Opening an exhaust too much will result in a loss of HP and torque . Either you need more airflow to fit your exhaust or you need to downsize your exhaust to create the proper back pressure .

Want proof ? Just check out Noogie vs Poop setup . Poop has the larger exhaust and lower numbers .......

[HTM Yaris]

Back pressure is a good thing . Some not alot . Without Backpressure(BP) there isn't any exhaust gas velocity . If no BP was a good thing all the real race cars would have exhaust gas being released straight from the exhaust port . ( Yes I realize that exhaust pipes also evacuate heat )


Try this , go turn on your garden hose . See how it flows ? To increase the velocity of the flow you can do 2 things 1. increase the volume of water or 2. partially cover the end of the hose with your thumb (creating BP) .

[largeorangefont]

I didnt read the entire thread but think I have a decent idea of what is going on.

Here is the first thing I will say here:

Comparing results from DIFFERENT DYNOS is not accurate and a waste of time.

Different dyno manufacturers read differently, and ambient conditions change from day to day. If you have dyno results before and after a mod on the SAME dyno, generally the gain (or loss) you see is close to accurate.

At this point, it looks like that if you want to fully realize the gains from a blitz SC, you will need addtional tuning.

A fuel controller may work, but if timing is still retarded, you are only going to LOSE more power. We need to find out what that box does. Lets say all it does is retard ignition timing. Then I would say remove the bot, get a fuel controller and adjust the fueling curve, run cooler spark plugs and always run premium fuel.

Adding a rising rate FP regulator is NOT a solution for a returnless car. There is really no mechanical fix to solve this particular problem. You are going to want a piggyback ECU or a reflash.

You guys are not going to fix this with fuel system mods. I assure you, you are not running out of fuel with a ~30 HP gain.

Peterpoop,

Your exhaust is fine, I would not worry about it. If you can get something to view your ignition advance in the meantime, do so.

[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]

Not adustable fuel pump. Adjustable fuel pressure regulator. Dyno guy is guessing that the fuel pump may be putting out sufficient max pressure but it could be regulated down too low for when we're boosting. A boost-sensitive fuel pressure regulator would tap into the vacuum line at the intake manifold and increase pressure when it senses boost pressures.

I'm starting my Internet research now.