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Discussion Starter · #1 ·
I've been having a BIG problem w/ detonation lately....motor's never been truely right, but it's finally gettin' to me.

I've got ported FRPP heads w/ '01 cobra pistons/rods....it won't stop detonating!! I'm gettin' sick of tinkering w/ it (almost a year now). I've got a Tweccer and have been doin' everything I can think of to get the motor to calm down, but it even pings on the stock '96 program!

I'm at the end of my rope w/ this thing. I'm thinking of dropping in a '01 4v. I just read a post from TEXASDEVILDOG where he was having similar problems w/ a 4v and added fuel then was able to add timing. So I'll try that. I've only been pulling timing not messing with the fuel tables at all. So frustrating.

Anyone have any other ideas? Or should I just part out the FRPP stuff and get the 4v crate motor and be done till schools out?

Thanks,

SJ
 

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Sounds to me like you need to get dyno time and an experienced tuner with access to an accurate air/fuel ratio set-up. Tweecer is a great tool, but it can be a total F*up if you havent got the experience tuning eec's. IMO you cant do the initial tune on the road or track, you can only tweek. It has to be done on the dyno.
Some things that may help.
Colder spark plugs,
are you using the correct plugs, FRPP heads use different plugs they are not the same as the stock or PI heads.
Less initial timing.
Look at your total advance.

Edit: colder plugs are better than more octane. Octane doesnt make HP only cools the fuel explosion.
 

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May I make a suggestion, see a reputable tuner and get it chipped. Fuel tables are as if not more important then timing. Many things need to be addresses, that most likely you are not knowledgable enough about.
 

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most likely you don't have enough gas.... cloged filter, bad pump ect....
 

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You definitely need to see what the fuel air ratio looks like, and have it adjusted right before you do anything else. I would reset the computer to the factory parameters, and reset the timing. Get your fuel air mixture right, then you can start with advancing the timing.

Your best bet is going to be to let a shop tune it for you on the dyno. Then, you can start messing with tweecer. Just my 2cents, and you can give me the change. Lord knows I need all the money I can get right now :D
 

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my girl had the same problem with her 95 5.0.... i had the timing retarded back to 6 degrees of base timing and it still knocked if you got on it. i got pissed and told her take it to ford i have no clue whats wrong and they replaced the pump and filter set the timing back at 12 and it hasn't happened since so i am almost sure that is your problem
 

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Discussion Starter · #7 ·
I'm using Autolite 103's right now...1 heat range colder than stock and full threaded plug, so those are right. The fuel pump was replaced when I put the SVO heads on last year, and recently replaced the fuel filter. So I don't think that's the issue.

Looks like some dyno time then! Thanks for your suggestions guys....Anyone been tuned by Steen Racing? I've heard some good things about their operation.

SJ
 

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What kind of compression ratio did the Cobra pistons give you?
 

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pistons

You may have answered your own question.

The 4V heads are 52cc, the 2V heads are either 47 or 42. If you used the 4.1cc dished piston with the late modes 42.5cc heads you have about 11.75.0:1 compression.

I can verify the numbers when I get to work. But I'm a thinkin that's the problem.

If you email me the head cc's and verift the piston dish I can compute it for you. [email protected]
 

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GreenMonster'96, by 'FRPP' heads did you mean SVO heads, or just the PI heads being sold by FRPP?
 

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pistons

It's true.

The cobra dish with the 2V heads make 11.75:1.

Stick some unleaded race gas in it. If the problem goes away it's pretty mich verified.
 

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pistons

Well that makes them 10.0:1.

We've had a couple of these things, with ported stock heads, make a noise that sounded like detonation but wasn't. It would rattle at the top of each gear.

It followed the heads from car to car, an were told that in the porting process there was something that wasn't getting oil any more.

Is this possible?
 

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Discussion Starter · #15 ·
Nah, I didn't have a problem w/ it until I replaced the pistons. I was running the stock short block with the SVO computer and no "rattling".....

I've dropped the timing advance to 14*, and I think most of it has gone away....I'll leave it there until I can get it tuned

Thanks,

SJ
 

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I ran '99 2V PI heads ontop of a stock '01 Cobra block and we CC'd the chambers and did the math and came out with 11.4:1 CR. I would have to run race gas (100 octane) unless I flipped the switch that took out 6 degrees of timing. Jerry road tuned the car in the heat in order to get it perfect. I also noticed that I could get away with pump gas and the added timing if I threw a bottle of the NOS octane booster, Sounds ghey but it did work and saved me from spending [email protected]

Now the motor is bulletproff and I'm running an SC friendly 8.5:1 CR and all is good execpt for the crack in the plastic radiator tank...DoH!

-Scott
 

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Discussion Starter · #17 · (Edited)
when I looked at everything I was running 18-19* advance....which for the SVO heads is about right except that I raised the compression to 10:1. So, I went with what one of the other guys (somewhere) said about running 18*on a T/A and just took out 4* to make up for the compression increase....it seems to have worked. Whether or not I'm making the most power possible with my set up this way, I don't know. I do know that it's not detonating everytime I give it gas which is the most important thing right now.

Anyone know for sure how much timing the SVO computer has? I'd like to get that EEC dumped and see....my car ran great on that computer but it has too much timing for me now.

I think I've figured out the Tip-in stuff on the EEC, which unless I'm wrong is what Jerry was messin' with on yours, Scott, while you were driving him around. You said that it was doing it bad when you first got on it right? Mine has been doing that up until now too.

SJ
 

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SJ, I made 256RWHP and 300RWTQ and that is not so bad for a Auto, IRS, MN12 (T-bird/Cat). Driveablity was right on and I'd rather have power then good gas mileage so that was not a factor. He messed with more then just the tip-in and after the tune I drove it all the way back from MI to the ATL.


"Sir, slowly step away from the blue paint can."
 

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Discussion Starter · #20 ·
That's awesome power from that setup!....I'm definitely gonna have to get a FordChip next time the come to VA,or NC.

SJ
 
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