Can I get your meaningful advice and suggestions on tuning?
#22
20-25 psi of FP will not work dude. he needs to tighten the afm and then maybe lessen his FP to stock levels but this is hard since the 255 flows a **** ton of fuel i bought a adjustable fpr for mine and it flowed less than my stocker no matter what i did to it so i went back to stock and 5-10 psi higher idle fuel pressure. he could tweak his ait to show a hotter engine bay enviroment and trim fuel up top that way as well.
#23
https://www.miataturbo.net/forums/member.php?u=121 ask the original he is still around how bout that. the first to run 400+cc injectors on a stock ecu.
You can trie to lean it out by lowering the oem fuelpressure (as stated above). As 440cc is more then double the amount youll need 20-25 psi @ 0psi boost.(loose vavuum connection off the oem regulator.) With the valve you can change this...Not sure what the reaction will be off the injectors due to the low fp.....
Be sure the afpr picks up the fp when boosting....but you are on your own there....
440cc fows enough to support you hp level @ stock fp (45psi) Limit yourself to this max pressure.... (link ecu does this too)
Please get a wideband for this kind of tuning....
Be sure the afpr picks up the fp when boosting....but you are on your own there....
440cc fows enough to support you hp level @ stock fp (45psi) Limit yourself to this max pressure.... (link ecu does this too)
Please get a wideband for this kind of tuning....
Anyways, I was able to resolve this issue by leaning out the RX-7 AFM another tick and regapping my plugs down to .032 from .039. The car is plenty fast and torquey now and NO hesitation from 4500 - 5500 as before.
20-25 psi of FP will not work dude. he needs to tighten the afm and then maybe lessen his FP to stock levels but this is hard since the 255 flows a **** ton of fuel i bought a adjustable fpr for mine and it flowed less than my stocker no matter what i did to it so i went back to stock and 5-10 psi higher idle fuel pressure. he could tweak his ait to show a hotter engine bay enviroment and trim fuel up top that way as well.
#24
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As i stated above i don't know what the minimum fuel injector pressure is to get it to work properly.... The 20-25 psi is a simple 1/2 of normal fp as the injectors are 2x as big as oem.
Of course you can fool the ecu to to give less fuel through the afm.
bypassing the oem fpr is done frequently with good results.
If you need less than oem fp because of bigger injectors just bypas the regulator and insert a valve in the bypass. This way you can control the fp @ the fuel rail.
The afpr will increase fp @ boost levels so nothing is wrong.
Of course you can fool the ecu to to give less fuel through the afm.
bypassing the oem fpr is done frequently with good results.
If you need less than oem fp because of bigger injectors just bypas the regulator and insert a valve in the bypass. This way you can control the fp @ the fuel rail.
The afpr will increase fp @ boost levels so nothing is wrong.
#26
You should see an initial drop in EGTs, but it would not be sustained. IIRC, you would see this if it is running too rich and the fuel in introduced and doesn't burn efficiently. The effect is it cools the EGT...not by hundreds, but by 25 - 50 degrees.
I need to do more research, so I'm not talking outta my @ss.
I need to do more research, so I'm not talking outta my @ss.
#27
I have another idea wrt your bouncing idle. I've got it too (BAD) and my AF at idle is fine.
When was the last time you adjusted your actual idle speed?
http://www.miata.net/garage/ignition.html
It's possible you could have a sticky IAC.
http://forum.miata.net/vb/showthread...ight=air+valve
When was the last time you adjusted your actual idle speed?
http://www.miata.net/garage/ignition.html
It's possible you could have a sticky IAC.
http://forum.miata.net/vb/showthread...ight=air+valve
#28
Dont want to be a hater BUT........
This is soooooo funny....your running a 255 walbro which is known for overpowering the stock FPR AND you have 440's installed....ON A STOCK ECU
just another classic case of "it runs fine BUT it doesnt idle properly and gets crap mileage (17MPG )and has hesitation etc etc"...THATS NOT RUNNING FINE THATS ****!
Get rid of the 255 and fit a 190LPH and then sort out your fueling properly. id say your hesitation is actually a rich condition...the stock ecu g0es way rich above 5000, and coupled with the 440's id say your drowning it in fuel.
The stock ecu uses fixed rate acceleration enrichment so the bigger injector you use the more fuel it dumps in when the throttle is cracked.doubling the injector size means double the fuel going in for the same amount of airflow which is going to give you hesitation problems.
your never going to get a half decent fuel curve with a stock ecu and no piggy back especially at that sort of HP and injector size.Anything you do with this setup is going to be a comprimise, and youll have to tune for the worst case in terms of knock, so everywhere else in the rev band is missing out on HP.
with your setup and HP id be looking at a megasquirt to sort it out.
THIS THREAD IS A TESTAMENT TO HOW TOLERANT THE MIATA ENGINE REALLY IS!
This is soooooo funny....your running a 255 walbro which is known for overpowering the stock FPR AND you have 440's installed....ON A STOCK ECU
just another classic case of "it runs fine BUT it doesnt idle properly and gets crap mileage (17MPG )and has hesitation etc etc"...THATS NOT RUNNING FINE THATS ****!
Get rid of the 255 and fit a 190LPH and then sort out your fueling properly. id say your hesitation is actually a rich condition...the stock ecu g0es way rich above 5000, and coupled with the 440's id say your drowning it in fuel.
The stock ecu uses fixed rate acceleration enrichment so the bigger injector you use the more fuel it dumps in when the throttle is cracked.doubling the injector size means double the fuel going in for the same amount of airflow which is going to give you hesitation problems.
your never going to get a half decent fuel curve with a stock ecu and no piggy back especially at that sort of HP and injector size.Anything you do with this setup is going to be a comprimise, and youll have to tune for the worst case in terms of knock, so everywhere else in the rev band is missing out on HP.
with your setup and HP id be looking at a megasquirt to sort it out.
THIS THREAD IS A TESTAMENT TO HOW TOLERANT THE MIATA ENGINE REALLY IS!
#29
Boost Pope
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+10 FTW on that one.
I ran air-cooled VWs for a long time, and those poor little things would suck down an exhaust valve or spin a rod bearing if you so much as spoke the words "Forced Induction" too loudly in their direction. The '71 and later 1600s weren't quite as bad, but you'd never even consider throwing 18PSI at one without spending at least $15,000 on just the case, crank, rods and heads. At that point, the only part left in the engine that said "Erbauen in Deutschland" was the dipstick. And you just accepted the fact that doing a bottom-end rebuild every other oil change was the way things were.
I hear so many conversations where people say "I'm running 42 PSI with no intercooler at 30 degrees BTDC base timing, and my gas tank is filled with cat urine and cheap whiskey" and I have to wonder just how loud a stereo you need to mask that kind of pinging. And yet for some reason the freeways are not littered with pieces of Miata engine case and rod.
Ours is truly a robust powerplant.
I ran air-cooled VWs for a long time, and those poor little things would suck down an exhaust valve or spin a rod bearing if you so much as spoke the words "Forced Induction" too loudly in their direction. The '71 and later 1600s weren't quite as bad, but you'd never even consider throwing 18PSI at one without spending at least $15,000 on just the case, crank, rods and heads. At that point, the only part left in the engine that said "Erbauen in Deutschland" was the dipstick. And you just accepted the fact that doing a bottom-end rebuild every other oil change was the way things were.
I hear so many conversations where people say "I'm running 42 PSI with no intercooler at 30 degrees BTDC base timing, and my gas tank is filled with cat urine and cheap whiskey" and I have to wonder just how loud a stereo you need to mask that kind of pinging. And yet for some reason the freeways are not littered with pieces of Miata engine case and rod.
Ours is truly a robust powerplant.
#30
Dont want to be a hater BUT........
This is soooooo funny....your running a 255 walbro which is known for overpowering the stock FPR AND you have 440's installed....ON A STOCK ECU
just another classic case of "it runs fine BUT it doesnt idle properly and gets crap mileage (17MPG )and has hesitation etc etc"...THATS NOT RUNNING FINE THATS ****!
THIS THREAD IS A TESTAMENT TO HOW TOLERANT THE MIATA ENGINE REALLY IS!
This is soooooo funny....your running a 255 walbro which is known for overpowering the stock FPR AND you have 440's installed....ON A STOCK ECU
just another classic case of "it runs fine BUT it doesnt idle properly and gets crap mileage (17MPG )and has hesitation etc etc"...THATS NOT RUNNING FINE THATS ****!
THIS THREAD IS A TESTAMENT TO HOW TOLERANT THE MIATA ENGINE REALLY IS!
Admittedly, the car IS a compromise. 93mimi had the car at the same or better performance levels AND 36 MPG highway. What I want to do is understand how to do this with stock components. I have three more motors in the garage and am looking to build a new motor for the other Miata for a bigger turbo setup with a complete stand-alone ECU. What is so much fun about this car, other than the *****-to-the-walls performance is that it is the ANOMALY. You shouldn't be able to do this withi this setup. I'm sure that someday, I may kill this motor, but I will have fun tinkering until then and then slip another motor in the bay.
As far as a forgiving motor, don't forget this IS a turbo motor (323GTX). It has forged rods from the factory. Albeit not for this much boost, but it IS a strong motor. That can't be said for the 1.8 and later powerplants.
#32
The stock ecu must really go rich at 5k because I just confirmed tonight that my vortech wasn't doing anything! I was running 6/7 psi on a stock fuel system (just the o2 clamp probably saved me!). I have done a compression check this winter and its still perfect. I didn't drive it very much with the turbo, thankfully. It hesitated (duh) until 5k, then it pulled well. It actually ran pretty well at partial throttle over all rpms. I finally got a pressure/vacuum pump and put 10psi to the fmu with no rise in fuel pressure. Learned my lesson.
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