GT40P heads, Cobra intake, full exhaust, C&L MAF- only 196.70 RWHP on DYNO!!!!!- HELP

[Lxpony]

my ignition is stock except an annoying blaster coil............. maybe I will swap the old one back...

 

[Lxpony]

First off is your TPS adjusted correctly and is it actually going into OL or WOT operation. In WOT operation the PCM uses tables to determine the AFR from trim values learned while driving. In my datalogs with Tweecer RT the AFR is pretty close to what is in the tables. For the stock PCM the tables are shooting for 12 to 12.5:1 at OL or WOT conditions and this is what my datalogs have shown. I have leaned mine to 13 to 13.5:1 and notice a definite improvement in performance.

If you vehicle isn't getting into OL or WOT then it would normally run at Stoich in closed loop operation.

Something is out of cal. in your setup and unless you can datalog what is going on your just shooting in the dark. I use Tweecer RT and a WB02 to tune.

Good Luck, Don

Don,
thanks for your reply- can you please tell me what the TPS voltage should be at WOT?

is a tweecer or custom burned chip the only way to correct the A/F ration at WOT this if I can correct it myself via a AFPR?

 

[IndyBlk5.0]

I think you blew a head gasket, have you done a compression test yet? Are your plug wires just bunched together or are they in separators?

 

[Lxpony]

no compression check yet, no coolant in oil, no oil in coolant, no loss of driveability- not starting problems, no idle problems. I will check but dont think I blew a HG- wires are separated with holders

 

[IndyBlk5.0]

I have none of the symptoms either, but mine is blown between the two cylinders.

 

[Lxpony]

SO did you change them?

did you do a compression test to find that out?

 

[BlackFox5.0]

I didn't really read all of the posts, but my friend had those plugs in his P's as well, for the same reason, the computer said thats what are for those heads. I told him to get rid of those things, and he put in Autolite 764's. I'll have to ask him to post on if it made any difference. Just because the Exlporer has a 5.0 doesn't mean it will have the same ignition....

 

[gt90stang]

Don,
thanks for your reply- can you please tell me what the TPS voltage should be at WOT?

*****At WOT it should be close to 5V. The stock values are:
WOT & OL breakpoint = 2.713V above idle setpoint.
Part throttle breakpoint = 0.039V above idle setpoint.
idle setpoint = 0.95V or so...must be below 1V.

is a tweecer or custom burned chip the only way to correct the A/F ration at WOT this if I can correct it myself via a AFPR?

*****Any programmable or custom chip can change the AFR tables.

*****When changes are made to the AFPR the only change you can make is to make the injectors seem smaller or larger to allow max. power at WOT. For AFR the PCM will learn from closed loop mode and apply it to OL and WOT operation. So if you have enough injector and FP then it will re-learn and be the same as long as the change is within the +/-20% capability of the PCM.

Good Luck, Don

 

[astronut1885]

Hey dude. I have a more modded example of your setup. GT40P heads (larger valves [1.96 intake, 1.54 exhaust]), Explorer (cobra/GT40) intake w/ 1" spacer, 1.7 roller rockers, E cam, full exhaust (including Prochamber), pullies, a T-5 tranny, MAF conversion (stock MAF, 19# injectors), and more crap I can't remember. Anyway, I hit the dyno at NED and I only made 258 rwhp and 281 rwtq. The car was very untuned, running pig rich and with 22* timing (I don't know how it didn't blow up). I got it home, tuned it out (42 psi fuel, 16* timing), and it got better. I've since added a full MSD ignition, and that's about it. The car picked up alot from dyno day, but I've yet to go back. I want to put a 70mm TB and 76mm MAF on there to open up airflow. I'm adding an A/C delete and electric fan in the next few weeks, and I'm hoping to make 300 rwhp/100 rwtq by summer's end. My full combo is listed at the link in my sig, but I'm just trying to give you an idea of what that combo is capable of. The cam and the tune are your two biggest enemies right now. Get an E cam, it's great for that combo.

 

[saleenx029]

I have a similar set-up, and I ran it too lean and blew the headgaskets, even though my car passed the compression test and leak-down, so make sure you inspect everything thoroughly to make sure you don't already have a problem, but if all your plugs read ok then it should be ok. Don't beat on it if you think it is too lean. I think that if you are running lean you should not advance timing like everyone says, although to get your power back up you will want to run more timing later, but figure the lean problem out first. AFPR will help, but probably won't solve the problem. I think the problem is your mass air meter/injector/computer set-up. Maybe put a wideband on the car and you can see how lean you are running. Custom tuning may really be the only answer.

 

[Lxpony]

how did you know you blew a head gasket if it passed the leakdown and compression tests???? did you just take off the heads for the hell of it? did the car run funny with them blown?

 

[saleenx029]

I knew the headgaskets were blown because:
1. I have blown them before and the heat signatures on the plugs were obvious (yor plugs look way better than mine did though)
2. The car ran like crap and had NO power
3. The car finally started smoking white smoke, so then we knew for sure