tuning problems, uncle meat where are you lol

brian98gt

Founding Member
Mar 12, 2002
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new jersey
running into some tuning issues on my 98 cobra. just had a vortech v2-sq installed and the car is leaning out at 5500 rpms and above. from what i gather this is a maf meter problem. i'm using a 83mm pro-m that i got with the supercharger. it was previously calibrated to accel 44lb injectors which i sold and used fms 42lb injectors instead. would a 90mm lightning maf meter work and would it have to be calibrated? i have one that i was going to sell and i was looking at the sct 2400 big air maf meter and it looks just like the 90mm lmaf meter with diff electronics. i also made 11lbs of boost on stock internals which i know is too much so i'm going to get a bigger pulley to get it down to 8 or 9lbs. at 11lbs it made 490 to the rear but i know at an unsafe a/f level.
 
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Sorry I didn't see this post until KT bumped it! ...and KT is right BTW, get that beeyotch tuned before you possibly hurt it. You'll also need to get whatever MAF you decide on calibrated to the size of the injectors. Probably the easiest thing would be to order the correct sampling tube for the pro-m which matches the current injectors if they make one.

U.M.
 
Sorry I didn't see this post until KT bumped it! ...and KT is right BTW, get that beeyotch tuned before you possibly hurt it. You'll also need to get whatever MAF you decide on calibrated to the size of the injectors. Probably the easiest thing would be to order the correct sampling tube for the pro-m which matches the current injectors if they make one.

U.M.

the guy tuning my car assures me that the maf meter is working fine and not being pegged, he says its just not getting the fuel that is needed. the a/f is fine up to 5500 rpm but once the boost starts going up over 9 and 10 it starts leaning out. he thinks maybe one of the fuel pumps i got is bad even though there new. i'm going with one size larger pulley which should bring the boost down and this should help a little, but i would think the fuel running out will still be an issue.
 
oh, and the guy tuning it is using that sniper special forces tuning software. 11lbs is too much for stock internals correct? is it the boost that kills the engine or detonation? how come a car can handle more boost with an aftercooler or methanol injection? i'm considering the afm mr freeze methanol injection kit
 
the guy tuning my car assures me that the maf meter is working fine and not being pegged, he says its just not getting the fuel that is needed. the a/f is fine up to 5500 rpm but once the boost starts going up over 9 and 10 it starts leaning out. he thinks maybe one of the fuel pumps i got is bad even though there new. i'm going with one size larger pulley which should bring the boost down and this should help a little, but i would think the fuel running out will still be an issue.
Maybe so. Have you thought about adding a BAP to increase fuel pressure?

oh, and the guy tuning it is using that sniper special forces tuning software. 11lbs is too much for stock internals correct? is it the boost that kills the engine or detonation? how come a car can handle more boost with an aftercooler or methanol injection? i'm considering the afm mr freeze methanol injection kit
I would think 7 or 8lbs would be the safe limit for a stock motor myslef. Either one of those (too much boost or detonation) though can grenade your motor! After coolers or methanol injection cool the intake charge thus reducing the chance of detonation and allowing you to increase engine timing.

U.M.
 
i've thought about the bap, i'm going to run it by the mechanic. my mechanic is going to put the bigger pulley on and he said he's going to possibly drill holes in the basket cause he thinks possibly that its not filling fast enough. i may also use the mr freeze methanol injection since it looks very easy to install. it runs off your boost and it uses your factory windshield washer fluid tank. any thoughts on this product?
 
Read the article I posted in your other post. 11lbs won't hut stock internals. 14lbs with a good tune and meth is just as safe as 8lbs without meth. Go to the other thread
 
ok, i've been getting this knocking noise that goes away after 3200 rpms, at first i was thinking some serious damage was done possibly during one of the dyno runs when the boost was hittin 11+ psi, but now i'm thinking maybe it has something to do with the imrc's. after 3200 the noise stops and the car runs great. any thoughts would be appreciated
 
You guys are really running 10 to 11lbs on the stock internals? I'm really surprised the factory motor hold up that well with the higher compression ratio's and all.

U.M.

Admittedly, I don't live my life 1/4 mile at a time. Most of my miles are cruising below 3k rpms on the highway. The only time I really burn through the gears is at the track and on ramps. But then I do take it right to 7k and I have bounced it off the rev limiter a few times in 1st after losing traction on the street.:nonono:
 
tell him to go up one pulley size , drilling some holes in the basket isnt a bad idea on the 98s I think they have the canister that the pump sits in so that is a possible problem , make sure its over half full of gas , MAF could be a problem , I would get one of the sniper 95mm bazooka MAF to go on it , matching parts always work better , but he should datalog the MAF to make sure its not pegged , 490rwhp would be pushing the 42s as well , so after you get the other pulley on it make sure hes dataloggin the MAF , if its not pegged I would check the duty cycle on the pumps and then might try bigger injectors if all that looks ok ....problems like this are why you have to have a datalogger , if hes just using the special forces and doesnt have the delta force or commando so that he can get full control of the PCM and still cant get it all figured out , I am sure he can email the file to Patrick at Sniper and get the changes it needs made and then emailed back to load on the flasher .....If I can assist let me know . I am a dealer for Sniper and would be glad to try to help ....
 
tell him to go up one pulley size , drilling some holes in the basket isnt a bad idea on the 98s I think they have the canister that the pump sits in so that is a possible problem , make sure its over half full of gas , MAF could be a problem , I would get one of the sniper 95mm bazooka MAF to go on it , matching parts always work better , but he should datalog the MAF to make sure its not pegged , 490rwhp would be pushing the 42s as well , so after you get the other pulley on it make sure hes dataloggin the MAF , if its not pegged I would check the duty cycle on the pumps and then might try bigger injectors if all that looks ok ....problems like this are why you have to have a datalogger , if hes just using the special forces and doesnt have the delta force or commando so that he can get full control of the PCM and still cant get it all figured out , I am sure he can email the file to Patrick at Sniper and get the changes it needs made and then emailed back to load on the flasher .....If I can assist let me know . I am a dealer for Sniper and would be glad to try to help ....

thank you very much for your help, i actually have the next size up pulley going on tomorrow. i will print your post and let my mechanic take a look, but you know how they can be. they don't like to be told what to do or for you to help them. after tomorrow i'll know a little more. my real concern is the knocking or tapping sound coming from my engine
 
thank you very much for your help, i actually have the next size up pulley going on tomorrow. i will print your post and let my mechanic take a look, but you know how they can be. they don't like to be told what to do or for you to help them. after tomorrow i'll know a little more. my real concern is the knocking or tapping sound coming from my engine

its my belief you dont learn anything by being a know it all , and you dont learn unless you ask questions , if he isnt sure he should call and talk to Patrick at Sniper and I know it can be fixed using the Sniper software , I have done hours and hours of reading on tuning , and have watched Tim Barth at modular powerhouse tune numerous cars , I love SCT software , really have not dealt with Diablo so im neutral when it comes to them , but I know any of it can do the same thing , its the person using it that makes the difference, not saying your guy is not a good tuner , just saying even the best get stumped , Tim told me my car was possessed by the devil both times hes tuned it because he had to spend more time than usual with it...... I went with Sniper because I liked the features that the special forces offers and so far everything I have used it with has been dead on ......but when you go to adding 2 fuel pumps , aftermarket MAF , bigger injectors and probably a little too much boost on your car than what would normally be considered conservative , then you can run into issues , if it is the MAF maxing out , simply swapping pulleys might help solve it ...... but a datalogger is a key part of dialing it in .......