SHM stroker kit, results... help.

[RedGTvert]

thanks man, I thought the B heads were the good ones.

Don't take me wrong, they are not bad heads. They flow decently, but lack the velocity of the c's or 03/04 heads. They do very good with FI, but N/A they cannot keep up with an equal set of 03/04 heads.

 

[RedGTvert]

yea, leaning out is what i would have expected as well. but every time they made it more rich, it got more power. it didnt want to be lean at all. (much to the shock of everyone in the shop).
the CR as advertised by SHM should be between 10.25 and 10.5:1. however, oddly, the Manley website lists the CR for my pistons at 10.96:1. is there a way to determine the compression of an engine after its built?
the intake and exhaust lift is 0.452.
duration @ .050 intake and exhaust is 209.
thanks everyone.

I kinda thought it would be 11.0:1 area. Maybe you have it backwards, leaning it out will give it more power. Which software was it tuned with.

Don't get too frustrated. Sometimes you need to play with the combo to get it right. Just throwing parts at it, does not automatically mean big gaisn, unless they work well together.

 

[RedGTvert]

I guess go more psi instead of ci's...

depends on which way you get more ci. If you want to do a 5.0, then a BB is better than a stroke for power. The BB unshrouds the heads very nicely.

 

[johnny98]

I kinda thought it would be 11.0:1 area. Maybe you have it backwards, leaning it out will give it more power. Which software was it tuned with.

Don't get too frustrated. Sometimes you need to play with the combo to get it right. Just throwing parts at it, does not automatically mean big gaisn, unless they work well together.

are you referring to the A/F ratio being 11.0:1 or the compression ratio? either way, yea, i would have expected leaning the compression ratio out would give it more power. that is the general rule of thumb. that was the first thing they tried to do when tuning it, and it lost power and detonated like a muthaf***a. however, the more rich it got (up to 11.4), the more power it produced and without any detonation.
it was tuned on a dynojet, and the only thing i saw on the computer was a program called 'winprep' or something like that.

 

[RedGTvert]

are you referring to the A/F ratio being 11.0:1 or the compression ratio? either way, yea, i would have expected leaning the compression ratio out would give it more power. that is the general rule of thumb. that was the first thing they tried to do when tuning it, and it lost power and detonated like a muthaf***a. however, the more rich it got (up to 11.4), the more power it produced and without any detonation.
it was tuned on a dynojet, and the only thing i saw on the computer was a program called 'winprep' or something like that.

Yes, guess the reason you got detonation when trying to lean it out was that 11.0:1 CR you are running. I am just wondering if they have a tad too much timing.

This is why I said, you cannot just throw parts at a car to make lots of power, unless the parts are matched real well. I am guess you called SHM, and asked for recommendations and this is what they gave you, so you bought it. I am still surprised that 11:4 is the leanest you could go, but with that CR, it limits you N/A. On a positive note, nitrous loves that type of CR, so if you were to go with this type of power adder, look out for the numbers then.

PS. I have seen 99/01 Cobras make 600+rwhp and 420+tq. Like I said, these things are not TQ monsters unless you have something on there like a 2.2L KB. I still say your numbers are not that far off. With a better tune, maybe 10 more rwhp.

 

[johnny98]

Yes, guess the reason you got detonation when trying to lean it out was that 11.0:1 CR you are running. I am just wondering if they have a tad too much timing.

This is why I said, you cannot just throw parts at a car to make lots of power, unless the parts are matched real well. I am guess you called SHM, and asked for recommendations and this is what they gave you, so you bought it. I am still surprised that 11:4 is the leanest you could go, but with that CR, it limits you N/A. On a positive note, nitrous loves that type of CR, so if you were to go with this type of power adder, look out for the numbers then.

PS. I have seen 99/01 Cobras make 600+rwhp and 420+tq. Like I said, these things are not TQ monsters unless you have something on there like a 2.2L KB. I still say your numbers are not that far off. With a better tune, maybe 10 more rwhp.

what would cause the a/f to need to be that rich though? that is what i still dont understand, and SHM doesnt have an answer for it either. the timing is at stock. when they tried to advance it, it started detonating again. SHM recommended the stroker and cam combination, and when i told them i was planning on a stage one head port, they said that would be even better. i was planning on a blower, so it is all kinda sad...
but, they are still decent numbers, and it drives well.
any ideas, anyone?

 

[Red35th]

That compression is pretty high to run on 93 octane. To cope with this they could either lower the timing, or the a/f ratio. They clearly chose the latter. The main problem is that your a/f ratio is quite high for a daily driver car on pump gas.

I am still trying to find the thread of a guy with a 96-98 Cobra. He had full bolt ons, longtubes, Dr. Gas offroad X pipe. Tuned by MPH in GA it put down 300rwhp, it had NO internal/headwork/cams done to it at all.

I still think that your numbers are 30hp low, but I have no idea why. Did HPP have any answers? Manny campaigns a 4v in NMRA if I recall correctly.

 

[mogs01gt]

Don't take me wrong, they are not bad heads. They flow decently, but lack the velocity of the c's or 03/04 heads. They do very good with FI, but N/A they cannot keep up with an equal set of 03/04 heads.

Yeah, you are right. That is what I was thinking. The B heads are the ones wanted for Forced induction.

 

[Dan_Soprano]

those numbers are pretty damn respectable in my book for a N/A 2 valve 4.6 bro........

 

[69fb00GT]

those numbers are pretty damn respectable in my book for a N/A 2 valve 4.6 bro........

It's a 4v


I would have the tuner take out timing and lean out the a/f. If that baby has some big ports you're gonna need more cam and more rpms to make the power you're looking for. Plus the bigger cams will help bleed off your cylinder pressures which is causing your detonation.

 

[johnny98]

I still think that your numbers are 30hp low, but I have no idea why. Did HPP have any answers? Manny campaigns a 4v in NMRA if I recall correctly.

Manny's only thought was that it could be just a bad head/cam combination. not much input other than that.

It's a 4v


I would have the tuner take out timing and lean out the a/f. If that baby has some big ports you're gonna need more cam and more rpms to make the power you're looking for. Plus the bigger cams will help bleed off your cylinder pressures which is causing your detonation.

Yes, Dan Soprano, if this were a 2v with these numbers n/a, i would be quite the happy camper. it is a 4v, however, leading to my quandary.
69fb00GT, what do you mean by helping to bleed off cylinder pressures, and this causing detonation? i am not familiar with this.

 

[69fb00GT]

cams with more duration leave the valve partially open during the compression stroke. This will lower your compression pressures, resulting in more friendly pump gas scenarios. Plus you'll probably pick up some more HP too if those heads flow well. Only problem, you'll probably be a little softer on teh bottom end.

Sounds to me like detonation is keeping you from respectable numbers....as posted above...if the tuner hasn't already tried pulling some timing and taking out some fuel..ask him to try it.

I believe i've also read that the 96-98 4v intakes are pretty restrictive...maybe you can get yours extrude honed or ported.

 

[RedGTvert]

what would cause the a/f to need to be that rich though? that is what i still dont understand, and SHM doesnt have an answer for it either. the timing is at stock. when they tried to advance it, it started detonating again. SHM recommended the stroker and cam combination, and when i told them i was planning on a stage one head port, they said that would be even better. i was planning on a blower, so it is all kinda sad...
but, they are still decent numbers, and it drives well.
any ideas, anyone?

It is becuase you are getting detonation, so the tuners is richening uo the mixture to avoid it. A blower with that combo is out of the question, uless you are ready to run 100, and that would cost an arm and leg to drive, that is why I say nitrous. A 200 shot on there would be sweet with your CR.

Hpw is your MAF reacting?

 

[RedGTvert]

That compression is pretty high to run on 93 octane. To cope with this they could either lower the timing, or the a/f ratio. They clearly chose the latter. The main problem is that your a/f ratio is quite high for a daily driver car on pump gas.

I am still trying to find the thread of a guy with a 96-98 Cobra. He had full bolt ons, longtubes, Dr. Gas offroad X pipe. Tuned by MPH in GA it put down 300rwhp, it had NO internal/headwork/cams done to it at all.

I still think that your numbers are 30hp low, but I have no idea why. Did HPP have any answers? Manny campaigns a 4v in NMRA if I recall correctly.

93 on pump gas is not as serious as you are believing. There is absolutely no reason it cannot be done. My new engine, when it is built will be running that kind of CR on pump gas, and it will run all day long.

30rwhp?? Not with that combo, sorry.