UPDATE: PI HEADSWAP & COMP CAMS 262 SWAP COMPLETE

97GTSTANG

Founding Member
May 25, 2000
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17
Virginia
Thank you to everyone that assisted me with the swap. The mechanic just completed the swap and test drove the car and it ran very well. The idle was not as lopey as i thought it would be, it was very mild actually. The engine was not shaking, it was smooth, no check engine light and drive was smooth.

I know on previous threats i was concerned about PTV issues, but since the car idles well and drives well can i be 100% sure that there are no PTV issues? If there was, how can i tell? He advised me to drive it for a few days before getting it tuned.

Should i purchase the SCT X3 and get the 3 free tunes and then get it dyno tuned to see if the tune worked well. Or should i just go to the dyno and get it tuned that way and purchase the SCT X3 from them? Any difference?

THanks again
 
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If I recall the SCT tuners do their job by advancing the ignition timing. Doing this will cause the engine to require more octane to run edficiently. When you increase the compression like you did when you put the PI heads on the motor you already increase the octane requirements of the engine. If you do both in conjunction with eachother its very possible the the eninge will likely become octane starved and you will run into detonation problems which is very undesireable.

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If I recall the SCT tuners do their job by advancing the ignition timing. Doing this will cause the engine to require more octane to run edficiently. When you increase the compression like you did when you put the PI heads on the motor you already increase the octane requirements of the engine. If you do both in conjunction with eachother its very possible the the eninge will likely become octane starved and you will run into detonation problems which is very undesireable.

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When i order the SCT wouldnt they konw not to increase timing? I do not mind using 93 octane if it will provide better driveability and more power.
 
Why not get the car dyno-tuned? :shrug: Then you don't have these things to worry about.

Why risk a mail order tune that's an IMPOSSIBLE perfect match for your car and run the risk of sending all your hard work up in flames?

I have difficulty understanding why people order these things. I mean... I can understand taking a stock motor, adding a supercharger, then running the tune provided by the blower manufacturer. It stands to reason that if you have a good tune for one stock motor with this kit on it, then it'll also be a pretty good match for the next stock motor with the same kit. The farther you get away from stock though, the less of a match this tune will be.

In your case, you've swapped PI heads onto a non-PI motor. I would imagine that you probably have other mods as well?

Either way... how is it conceivable that some desk jockey in another state is going to be able toss together a tune for these mods over the phone? If there's a mistake, who pays that cost?

On the other hand, you strap this thing to a dyno, the tuner looks at your AFR, Timing, Mods, temp and baro pressure and tunes YOUR car. How is this not a good thing? :shrug:
 
Why not get the car dyno-tuned? :shrug: Then you don't have these things to worry about.

Why risk a mail order tune that's an IMPOSSIBLE perfect match for your car and run the risk of sending all your hard work up in flames?

I have difficulty understanding why people order these things. I mean... I can understand taking a stock motor, adding a supercharger, then running the tune provided by the blower manufacturer. It stands to reason that if you have a good tune for one stock motor with this kit on it, then it'll also be a pretty good match for the next stock motor with the same kit. The farther you get away from stock though, the less of a match this tune will be.

In your case, you've swapped PI heads onto a non-PI motor. I would imagine that you probably have other mods as well?

Either way... how is it conceivable that some desk jockey in another state is going to be able toss together a tune for these mods over the phone? If there's a mistake, who pays that cost?

On the other hand, you strap this thing to a dyno, the tuner looks at your AFR, Timing, Mods, temp and baro pressure and tunes YOUR car. How is this not a good thing? :shrug:

I am going to get it dyno tuned. I was just saying since the tuner will use the SCT X3 anyways, i was thinking i get it from AM or somewhere like that and use the tune they send with it and then i will take the SCT tuner to the dyno and see if it is close to what the Mail tune was. just for comparison reasons i guess. Also i think the the dyno shop charges the same for an SCT tuner without any tune and from online i can get 3 tune.
 
Personally, I wouldn't run the risk of an out-of-the-box tune. Purchase the tuner and setup a dyno session at the same time.

Who knows, if you buy it directly from the dyno-tuner, you may get some sort of package price on the dyno time (even if you end up paying slightly more than you would for the same tuner from say... E-bay).
 
If I recall the SCT tuners do their job by advancing the ignition timing. Doing this will cause the engine to require more octane to run edficiently. When you increase the compression like you did when you put the PI heads on the motor you already increase the octane requirements of the engine. If you do both in conjunction with eachother its very possible the the eninge will likely become octane starved and you will run into detonation problems which is very undesireable.

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The added compression is not that big of a deal in his case. He with with bigger cams, and the bigger cams actually bleed off more compression than factory ones.

Also, when you tune a vehicle, you do not just add timing. You are also adding fuel, among lots of other things.
 
I know that when you have a professional tune on a dyno that you adjust A/F ignition timing and other things, but i was just saying that the OTC tunes you get when you get the SCT3 are mainly ignition timing advances. But yes, get a dyno tune, thats what I'm doing on mine.
 
They were degreed in a sense when the mechanic put the timing set on. There is only 1 way they can go when you time those motors. If you're in the wrong place, which from my experience you can't be then the motor wont even turn over for the valves are making contact with the pistons

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He did say he checked the timing several times, but if they were way off, you are saying the car will not even turn over, but since it did, is it safe to say there is no PTV issue? Like i mentioned earlier, i do not hear any knocking or ticking sound.
 
I would degree them myself but if truth be told probably more people running around without them degreed than with LOL , I would check compression from one bank to the other , I am down in Bedford Va and can tune it for you and can guarantee my pricing will be alot cheaper as well and I am SCT certified tuner
 
I didn't have mine degreed and have had zero issues in nearly 75,000 miles. Don't sweat it because if you did have any PTV it's too late to worry about it. If it runs strong you are golden.

Good to konw i am not the only one. Just hope that there is no PTV problems that i dont konw about. Cause i dont hear any knocking or see any excessive shaking.
 
They were degreed in a sense when the mechanic put the timing set on. There is only 1 way they can go when you time those motors. If you're in the wrong place, which from my experience you can't be then the motor wont even turn over for the valves are making contact with the pistons

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That is not degree'ing them, that is just simply lining up the dots.

Cams are almost never cut to the exact centerline that they are supposed to. If a company says they are supposed to be a 110 intake centerline, they could very well be a 106 intake centerline. If you get a cam that is a 226 intake duration that is supposed to be a 110 intake centerline but infact is really a 106, you will be tearing the motor apart real quick if you decide to start it up.

There still very well could be PTV contact, but you wont hear it and will more than likely do 0 damage. The valves are going to expand more at 6,000 rpm than they will at 750 rpm. It will more than likely not cause any issues. The only way you will really be able to tell is if you ever decide to tear the motor apart.
 
I will continue to drive it and see. I have not taken it past 4K rpm yet. The mechanic and i were listening for knocking or ticking or excessive shaking, but when it was reved up to 4K it pulled up smooth and didnt hear anythign out of the ordinary. I have asked him to do a compression test on a couple of the banks.

So you are saying it might not hit at 4K but might at 6K? i thought the valves will only expand to a certain point and taking it from 4K to 6K means its moving faster not further down?
 
Metal is going to expand to a certain point, the faster you spin it, the more it's going to expand.

If it has not hit yet, then it's not going to. If for some reason it does, it will only lightly kiss the piston, but wont be enough to do any sort of damage. Quit worrying and go beat the piss out of it.
 
Metal is going to expand to a certain point, the faster you spin it, the more it's going to expand.

If it has not hit yet, then it's not going to. If for some reason it does, it will only lightly kiss the piston, but wont be enough to do any sort of damage. Quit worrying and go beat the piss out of it.

Thanks for the reassurance. its just that i have been reading everywhere that i should have asked the mechanic to degree the cams or else it will have PTV so i was really concerned. I will bring it up to 6K rpm after a few more days of driving to break it in and then update on the status.

I will definately get it dyno tuned by a professional.