ok guys heres the setup: 99 Z24 5spd with gm s/c kit
-2.6" pulley boys quick change
-ford brown top 370cc injectors
-cooling mist "be cool" alcohol injection set to come on at 4psi
-vortech 12:1 fmu
-casper electronics adjustable fmu 25-60psi
-walbro 255
-Apexi SAFC2
the car also has fully ported and polished head, and the secret cams as well as 59mm tb, header and full 2.25" exhaust.
I have my Apexi setup like this:
-lo throttle -30% @ 1000rpms
-th point = 30lo 75hi
-correction +-30
-7000rpms
i havent messed too much with the apexi yet, i have access to a wideband which i plan on tuning with but i just am looking to get the car tuned decent enough for the next few weeks.
The car is running terrible right now, it will start up and idle decent but if you just let it idle it seems to like load up and then the idle chugs alot and is missing. I havent even taken the car out to drive yet because i want to get this idle straight first. Any ideas at all please help me out, i need to have this car done by the weekend, help!!! Thanks guys,feel free to ask any questions im going to be checking back on this post as much as possible.
Your injectors are probably to big. I've got RC 320's in mine and have the FMU turned all the way down (3:1) and anywhere between 22% - 32% of the fuel pulled out with the AFC on the Hi th. settings. I still run a A/F of 10.8 - 12.2 so I can still take out more fuel and run better then I am now.
"The FACTS are always subject to CHANGE once the TRUTH is applied"
"In the entire history of man the only stupid questions are the ones that don't get asked"
I agree with Gary. Your injectors are too big. The kit only comes with 310cc injectors
Jason
99 Z24
#25 to register on JBO!!
Racers Edge
Johnny Mack Turbo Systems
Engineered Performance
th kit does come with 310cc i agree, however im not running 4.5 psi and my engine is also not stock. 310's woulda made me go lean under boost, the 320cc may have worked and im currently looking for a set of ford red tops to try out, but i have a feeling in the top end those as well may go lean. The fmu i have no idea about, ive heard so many different settings i honestly have no clue, right now im not even worried about my ultimate performance because im hitting a dyno within a few weeks, i just need to get it tuned in decent enough to drive now and to get me to that dyno which is about 100 miles away. I had a buddy with this exact same setup run his fmu at 12:1 and he was rich but not excessively. I have no idea how your running 3:1 thats just nuts but if its working for you thats awesome man. Any more help out there??? this tuning thing frustrates the hell outta me
I'm running 6.5-8psi with a built motor and water/methanol... If I remember right the stock computer can't handle anything over 320cc injectors at idle.
"The FACTS are always subject to CHANGE once the TRUTH is applied"
"In the entire history of man the only stupid questions are the ones that don't get asked"
jimmyc99z24 wrote:th kit does come with 310cc i agree, however im not running 4.5 psi and my engine is also not stock. 310's woulda made me go lean under boost, the 320cc may have worked and im currently looking for a set of ford red tops to try out, but i have a feeling in the top end those as well may go lean. The fmu i have no idea about, ive heard so many different settings i honestly have no clue, right now im not even worried about my ultimate performance because im hitting a dyno within a few weeks, i just need to get it tuned in decent enough to drive now and to get me to that dyno which is about 100 miles away. I had a buddy with this exact same setup run his fmu at 12:1 and he was rich but not excessively. I have no idea how your running 3:1 thats just nuts but if its working for you thats awesome man. Any more help out there??? this tuning thing frustrates the hell outta me
ok a couple things. You were giving some info and then you shot it down. If you have not driving your car you will not know if it is lean or not. Sounds like you have too much fuel at idle. What is your AFPR set at?
FU Tuning
Your def running too rich at idle.Whats your idle fuel pressure at?With those injectors you shouldnt need an fmu as long as you have a s-afc.When i got my car dynoed it was running too rich at 7-8 psi.If you put on a 12:1 fmu,your gonna have raw fuel pouring out of your exhaust and your car is gonna run like garbage.
Peter
'06 Cobalt ss/sc W/G85 Package
Gm Stage II W/2.79" Pulley
K&N Drop In Filter
Custom Magnaflow Dual Exhaust
ptrblkz24 wrote:Your def running too rich at idle.Whats your idle fuel pressure at?With those injectors you shouldnt need an fmu as long as you have a s-afc.When i got my car dynoed it was running too rich at 7-8 psi.If you put on a 12:1 fmu,your gonna have raw fuel pouring out of your exhaust and your car is gonna run like garbage.
Why don't he need a FMU? You have to be able to raise fuel pressure under boost. He does not have the GM reflash. SAFC does not run off boost, but RPM. He could turn the AFPR up and get fuel that way but he will still have the same problem at idle. He needs to lower the AFPR at idle, and use the FMU to get fuel under boost.
FU Tuning
hey john sorry man i dint mean to shoot down anyone thats not what i meant to do, i agree with you though i def need an fmu without a reflash, the 12:1 may be a bit much but i have a few other disks (8:1,6:1,4:1) i can try out once the car is running decent under idle. I have access to a wideband which i plan on throwing on it once its decent under idle but as of right now its def too rich. As for my afpr well heres the thing with that, im kinda perplexed with it. I installed a f/p gauge on my fuel rail today and then i figured id be able to tweak the f/p but i start the car up and it is at about 47psi, i move the top allen head and it really doesnt do much, i dont seem to be able to get it to go much under 40psi when the car is running at idle, any ideas? the gauge is brand new and an autometer so i dont think its that. The afpr i have is the casper electronics one help me out guys.
jimmyc99z24 wrote:hey john sorry man i dint mean to shoot down anyone thats not what i meant to do, i agree with you though i def need an fmu without a reflash, the 12:1 may be a bit much but i have a few other disks (8:1,6:1,4:1) i can try out once the car is running decent under idle. I have access to a wideband which i plan on throwing on it once its decent under idle but as of right now its def too rich. As for my afpr well heres the thing with that, im kinda perplexed with it. I installed a f/p gauge on my fuel rail today and then i figured id be able to tweak the f/p but i start the car up and it is at about 47psi, i move the top allen head and it really doesnt do much, i dont seem to be able to get it to go much under 40psi when the car is running at idle, any ideas? the gauge is brand new and an autometer so i dont think its that. The afpr i have is the casper electronics one help me out guys.
Ok. How much are you turning the allen screw? It might take many turns to get it to move. You should be able to get it under 40psi. I had my turbo car at 32psi at idle. Also you might be rich at idle that does not mean you can't drive it. I would drive it some. With your pressure that high it will probably be rich even out of boost, and in boost. I will say having a adjustable FMU (just turn of the screw) is soo nice.
If need be turn the allen screw as far out as you can and see what your read.
FU Tuning
Quote:
Why don't he need a FMU? You have to be able to raise fuel pressure under boost. He does not have the GM reflash. SAFC does not run off boost, but RPM. He could turn the AFPR up and get fuel that way but he will still have the same problem at idle. He needs to lower the AFPR at idle, and use the FMU to get fuel under boost.
Im going by my car and what my wideband says.At 8 psi these 35lb injectors were spraying more than enough fuel.I had to pull alot of fuel away with the s-afc.I had my fpr set to 32-35 psi at idle and it still supplied plenty of fuel on the top end.
Peter
'06 Cobalt ss/sc W/G85 Package
Gm Stage II W/2.79" Pulley
K&N Drop In Filter
Custom Magnaflow Dual Exhaust
i'll have to see whats going on with the afpr tomorrow, i just cant seem to get it under like 38-40psi, i turned it all the way down and that was as low as i could get it, all the way up went above 60psi. I have 2 t fittings in line on the vacuum off the afpr, one of them is a f/p riser, the other is my fmu, could these be messing with the fuel pressure or no? Im a complete novice with this tuning thing, im doing my best but i will be the first one to admit its alot of educated guessing. I wish i woulda bought an adjustable fmu now but i guess im stuck with this one for now. im told the apexi can take fuel out under boost though so i think i should be ok once i get the wideband hooked up to it and tune the car with that under boost. I guess i could drive the car now with it running rich but it just doesnt sound very good, sinds kinda lopey and irratic under idle.
ptrblkz24 wrote:Quote:
Why don't he need a FMU? You have to be able to raise fuel pressure under boost. He does not have the GM reflash. SAFC does not run off boost, but RPM. He could turn the AFPR up and get fuel that way but he will still have the same problem at idle. He needs to lower the AFPR at idle, and use the FMU to get fuel under boost.
Im going by my car and what my wideband says.At 8 psi these 35lb injectors were spraying more than enough fuel.I had to pull alot of fuel away with the s-afc.I had my fpr set to 32-35 psi at idle and it still supplied plenty of fuel on the top end.
You are running a RSM kit? If so you have there program then.
FU Tuning
Dumb question time.. So you dont need the reflash if you have this GM charger on the pre 2k motor?
~2014 New Z under the knife, same heart different body~
______________________
WHITECAVY no more
2012 numbers - 4SPD AUTOMATIC!!
328 HP
306 TQ
^^ Its not that you don't need it, its just that there is no reflash available for a pre 2k
I work on Wall Street, but didn't force you to take out a loan you couldn't afford.
Mikey (drpdcavi) wrote:^^ Its not that you don't need it, its just that there is no reflash available for a pre 2k
Gotcha, I kinda thought that but wasnt sure.. Thanks.
~2014 New Z under the knife, same heart different body~
______________________
WHITECAVY no more
2012 numbers - 4SPD
AUTOMATIC!!
328 HP
306 TQ
the gm reflash is a conservative reflash based more upon reliability and driveability than performance, with proper tuning, (which i have yet to figure out lol) and the use of a wideband you can get alot better performance out of the s/c, especially when running smaller pulleys, cams, and headwork. my biggest issue right now is my base fuel pressure, i have an adjustable fuel pressure regulator and gauge tapped on the fuel rail but i just cant seem to the pressure below 38, and im looking for about 30psi
if i can get this fixed then i can really start tweaking it with the apexi and wideband, any ideas guys?
Quote:
You are running a RSM kit? If so you have there program then.
I got this kit like 5 years ago.Reflashing these computers back then was either a hit or a miss.I think i got a miss because it was running lean right out of the box.If it had a reliable tune,i wouldnt be messing around with all this tuning crap.
I hear there programming is alot better now.Id see if i can send my ecu to them to get reflashed again,but i dont even have the s/c on my car anymore.I dont know what im gonna do with it.Either sell it or put it back on.Ive been having too many issues with the engine lately thats why i took it off.
Peter
'06 Cobalt ss/sc W/G85 Package
Gm Stage II W/2.79" Pulley
K&N Drop In Filter
Custom Magnaflow Dual Exhaust
update: well i figured out why my f/p was so high, the casper only adjusts from 35-60psi, i was able to get it down to 35psi today but its still too rich, upon initial startup the car sounds decent, but it left to idle for a couple min you can see and hear it getting loaded up. Here are a couple questions for the gurus out there... First off my fmu is too big, i know this, i have a few extra disks to play with, any ideas which might get me decent performance and driveability for now until i can get the wideband on it in the next week or so ? I have a 8:1,6:1, and 4:1 disk. My thought was the 4:1 because of what John317 had told me earlier in this thread. The other question is this - my fuel pressure gauge on my rail reads 35psi, when i throttle the car up the pressure goes down to about 25-30psi, is this normal, i kinda thought it was supposed to go up, maybe im wrong. The only other thing i ask is if my afpr only goes to 35psi, and with the brown tops i need to be around 30psi hwo the hell do i fix this? can i take out more fuel using the safc? or do i just need to either get another afpr that can go from 25-60 or just get a set of ford red tops and run those? please help guys im seriously ready to just tear this thing off here and sell it
