help with build, 98, s trim, 11:1, built block

[b00sted4v]

Alright so i have a 98 cobra, high compression 11:1 with a vortech v1 S trim.
Everytime i get it up to the tuner/dyno it starts to break up at 4200rpms and then around 5200rpms. If driving the car you can feel it almost like it is dropping cylinders.
I replaced everything ignition wise on the car with all new msd brand parts. I m running tr-6 plugs gapped at .032(should these be tighter with the high compression)
Have been up to the tuner 4-5 times with the car and starting to get aggravated after $10,000+ dumped into it.

just looking for some input before I send the car out to a local mustang performance shop.

Also before the engine and tranny build the car just had a v1 s trim with bassani x pipe with cats and ran perfect, going 12.6 @ 117 mph @ the track on bfg street tires

 

[pacific4v]

Can't wait to see some numbers! Exact same setup as my car, 11:1 5.0 stroker, si-trim, A/A intercooler, and E85. I street tuned it so it hasn't been on the dyno. And I haven't had any ignition problems like ur stating. What fuel are u using, how much boost?

 

[b00sted4v]

just on 93 pump now to get some base numbers. Will be on E85 once get running 100%
As of right now just 5psi, looking to run 12-14

 

[b00sted4v]

Can't wait to see some numbers! Exact same setup as my car, 11:1 5.0 stroker, si-trim, A/A intercooler, and E85. I street tuned it so it hasn't been on the dyno. And I haven't had any ignition problems like ur stating. What fuel are u using, how much boost?

What kind of plugs are you using and gapped at what?
thanks

 

[4valved]

In his post he says ngk tr6 gapped at .32

 

[b00sted4v]

In his post he says ngk tr6 gapped at .32

ummmm no he doesnt...

 

[crazycarlo]

I'm assuming you had the problem before u made the switch to MSD units. If u have the coils just be aware a lot of ppl have had problems with them and most ppl prefer the stock units.

Also try a colder plug like the BR7EF. I used them and they solved a problem I had with my car breaking up man. The gap is fine ESP with the low boost you are running now.

 

[crazycarlo]

I'm assuming you had the problem before u made the switch to MSD units. If u have the coils just be aware a lot of ppl have had problems with them and most ppl prefer the stock units.

Also try a colder plug like the BR7EF. I used them and they solved a problem I had with my car breaking up man. The gap is fine ESP with the low boost you are running now.

 

[4valved]

ummmm no he doesnt...

Yes he does.................

 

[b00sted4v]

oh dont see him mention anywhere that he was running tr-6 gapped at .032 but whatever

 

[b00sted4v]

I'm assuming you had the problem before u made the switch to MSD units. If u have the coils just be aware a lot of ppl have had problems with them and most ppl prefer the stock units.

Also try a colder plug like the BR7EF. I used them and they solved a problem I had with my car breaking up man. The gap is fine ESP with the low boost you are running now.

yes problem was happening before msd ignition parts added, i just ordered them plugs see how that goes. I figured .030 at tightest with 11:1 and only 5-6 psi

tuner mentions crank sensor, bad injector, mechanical

I also just added a boost a spark and same results on dyno

 

[4valved]

Dude I didn't know you were the op

 

[MLS]

Drugs are bad m'kay.

 

[encasedmetal]

OP- if it's breaking up at 2 different spots and not inbetween it leads me to believe it's not spark related. now I would concur to ditch the msd coil packs and use oem units with 9mm wires and your tr6 plugs gapped at .30, but if a BAS didn't help at 5psi- it ain't spark related. a few things to check out to help:
simple- datalog your maf ad counts, is it a smooth line? what happens to the curve when the car breaks up?
simple- is it actually mild detonation instead of spark blowout. from your description of the symptoms this is what I think it is. check the plugs and see how the timing looks

 

[crazycarlo]

Encased if the OP is still using the setup I sold him off my car it's a PMAS HPX maf in a vmp tube. Also do you happen to know what kind of timing it is running? I'm sure the tuner has tried running lower timing to rule out detonation like mentioned above.

 

[98 Saleen Cobra]

Interesting.. If the Blower section I didn't see it was on 93.. It's very possible that it's detonation..

 

[encasedmetal]

Encased if the OP is still using the setup I sold him off my car it's a PMAS HPX maf in a vmp tube. Also do you happen to know what kind of timing it is running? I'm sure the tuner has tried running lower timing to rule out detonation like mentioned above.

HPX are notorious for being POS, not saying his is, but it is very simple to determine if it's the culprit which it very well could be. a bad or dirty maf will drop voltage at no certain point in the rpm range, which drops load and creates big issues similar to what he's experiencing. but any tuner worth his salt would see it in the logs

 

[pacific4v]

What kind of plugs are you using and gapped at what?
thanks

I'm running tr6 plugs and I believe they're gapped around .028-.030. I'm around 10-12psi with a c.o.p. conversion.

 

[crazycarlo]

Hmm maybe it is. I never had any problems with the maf. It was blow through and was awesome when I had it. But your right it should be seen by the tuner. What pumps and injectors are on the car?

 

[b00sted4v]

60lb injectors, 255 pump with kb bap