Lots of roasted pistons. Is the basic pulley'd Cobra safe?

[stangfreak]

this is a good thread. yes a lot has to do with the tune. ifyou got a crappy tune then say bye bye. more hp you will need to change the maf, fuel system. just what was stated above people who are running with a pegged maf are asking for trouble.

but let me just say something. this might sound crazy, bc im a boostaholic. BUT, boost is NOT our friend. i believe boost is whats causing these piston damage and lean conditions. 15 psi is it safe? i have no idea. only time will tell. do i believe that ford put crappy pistons in our cars? maybe.

 

[SmokenGRA03]

I dont think its all because of "BAD" tunes! (Bad tunes can blow your engine) What I'm saying is, some where down the line (30k to 70k) you will have to get new pistons! The Teflon will come off and you WILL get piston slap (TICK). I dont care if its stock or if its MODED to hell. You will have to rebuild it some day....(WEAKEST PART IS THE TEFLON PISTONS!!!!!....Been there done that after 10K)....

 

[Chonger]

Originally posted by SmokenGRA03
I dont think its all because of "BAD" tunes! (Bad tunes can blow your engine) What I'm saying is, some where down the line (30k to 70k) you will have to get new pistons! The Teflon will come off and you WILL get piston slap (TICK). I dont care if its stock or if its MODED to hell. You will have to rebuild it some day....(WEAKEST PART IS THE TEFLON PISTONS!!!!!....Been there done that after 10K)....

Yeah. I read your previous post (long and detailed!!) and thank you for it. I am learning from everyone else on the forum. I love the internet.

 

[PhillyCobra]

Dowsn't really matter functionally if teflon wears off pistons. It's really there primarily for noise control.

My take on this debate is as follows:

1.) Any mod that improves power can decrease engine life. It's all a compromise. I would be willing to compromise up to the point of about 500 rwhp with a 2.80 inch pulley from what I've seen with our engines.

2.) Key is how you drive it. A 12 second quarter mile is a lot less damaging than prolonged boost in a high gear on the road. Most stories of blowing up are on the street.

3.) Tune is the key-- not just A/F but timing. The tune should be dyno checked periodically, and be set safe so a bad tank of gas won't blow you up. Can also check plugs periodically for signs of detonation.

4.) Always use the same gas, which you know is from a reliable station, if possible. If you're going to race, particularly prolonged on boost, add some 100 or 104 octane unleaded fuel, if possible. Stay away from other octane boosters. Change fuel filter every 10,000 miles or so.

5.) Stay away from disabling your boost bypass, as it prevents heat buildup, which will start you off at high temps before you even get into the boost.

My 2 cents.

 

[nuxx]

ALL IN THE TUNE

That's all I can say. If you have a good tune, you'll be set. Even though I think my tune is ok, I still want to get a better, "safer" one. I had the Predator on both my 03 and 04, I think in the end going the dyno tuned chip route is the only choice.

Also the type of driving you do... I hardly go WOT and try to never pass 6k. If you got WOT 10, 20, 30 + times a day and hit the redline, I don't think your car will last very long... Also keeping in WOT for over 15-20 seconds will pretty much kill the engine, esp. in higher gears...

Mods like headers should help too, they help get heat away from the engine. Heat exchanger is a good idea, cold plugs, etc... When I get my 2lb lower put on, I'll probably get some headers too, then get the car retuned to around 11.5:1 across, and starting at a lower RPM. My tune right now has 13.x:1 until ~ 3k where it hits 12.1:1.

But yeah... I'm more paranoid than anyone that my car is a ticking timebomb... but if it goes, I have a few aces in my sleeve
-Peter

 

[orange2004cobra]

Like I posted ince before..
I am contemplating 10 to one pistons, a fuel sys upgrade, and going to a 4 in pulley...
Just the comp increase {2 or so points} will net me more bottom end, and no need for more boost, the eaton would make all I would need, for my street car that is..
Of course I am also thinking about going to a 3.27 gear, only shift 3 times at the track, and help with traction.
My biggest question is why go for so much more h.p. from a car that will not hook w/o major modification?
If someone really set up the chassis in these cars, with stock power, they would run high 11's...
just my opinion of course...
I need a drink...
L.

 

[cobra101]

Great thread. I have 6k miles on my car since adding the 2.75RR. Mileage is now at 19k total. No problems at all. I don't know what my max timing is (it was tuned by socaldiablo) but my a/f is pig rich up top. I am pretty sure my timing is ok especially since I haven't dyno'd as high as some others with similiar mods. I will datalog soon on my predator and see what the max timing looks like. I am also hoping for 100k miles plus, I think it is very possible.

 

[Chonger]

So do you automatically assume the roasted pistons on the non-aftermarket blown cars are from a bad tune? There have been a few with supposed "good tunes" that have bought the farm. Several of these cars with only a couple of thousand miles on them. I am not talking about the KB or Whipple cars because at those HP levels anything goes.

Some of you guys are running nitrous, lots of boost, and thrashing on the car all of the time. Others have problems w/in a few thousand miles. I can't believe "Its all in the tune". Maybe a combination of both.

 

[nuxx]

Originally posted by Chonger
So do you automatically assume the roasted pistons on the non-aftermarket blown cars are from a bad tune? There have been a few with supposed "good tunes" that have bought the farm. Several of these cars with only a couple of thousand miles on them. I am not talking about the KB or Whipple cars because at those HP levels anything goes.

Some of you guys are running nitrous, lots of boost, and thrashing on the car all of the time. Others have problems w/in a few thousand miles. I can't believe "Its all in the tune". Maybe a combination of both.

Tune, Driving Habits, and the luck of parts not failing...
-Peter

 

[vipergts281]

So how much are a set of better pistons?

PhillyCobra-- How hard is it to change the fuel filter.

And personally, I think it is in the tune, your driving habits, and just plain old luck. Within 16,000 miles I had a new clutch and tranny put it. Some cars just aren't built as well as others.

 

[11secCobra]

Originally posted by P_Lomez
Also run a higher octane. Higher octane = slower burn = cooler burn temp = less detonation

actually a higher octane gas burns at a higher temperature than lower octane, thats why lower octane gas will detonate easier

 

[sam]

just seems to me that there have been factory supercharged engines for years now. some of the problems we see with the cobra here is the fact that we like to tweak and race them. and not to mention dyno the hell out them everytime another change has been made. also as far as top end speed, that should be avoided all together with pullied cars. the motor problem that has surfaced was the tick. svt has tried to address this ,but this seems to just be an inherated problem with the 4 valve motor. its an annoance more than something that would cause catastrofic engine failure. mileage all depends on how fast you spin the blower and how many times you spin the blower.

 

[PhillyCobra]

Fuel filter change is a pain, as it's hard to get too in the rear wheel well. You also need to buy or borrow (Autozone) a fuel line tool.

There's plenty of threads on this forum about changing it if you don't have the factory service manual.

 

[oldnfast]

Originally posted by VintagePorscheG


They figured we wouldn't be able to leave it alone so. They expected us to:

1. CAI or K&N
2. exhaust
3. Lightning pulley (2.93)
4. Chip

I visited SVT last year. They told me the above plus...
1. With those mods the motor should last at LEAST 100k with
good maintenance (not if you race every weekend).
2. The motor was actually designed to last 50-75k @ 600hp.
But don't expect anything close to that if you take it to the
track every week.
3. We gave you a tough, high-tech motor. But, even an F-1
engine is only good for one race, and that's as high-tech
as they come.

"The only substitue for cubic inches is cubic money. The only substitute for a race motor is another race motor." - Don Gartlits

Basically, the more hp the shorter the lifespan.

 

[n0xlf]

I have a engine safety solution for all of you...Come move to Colorado...We have a built in safety net called altitude...

Seriously, I bet our motors will last forever...We are about 100 HP down from the rest of you after mods....I've run 29 degrees timing on a lean tune with no pinging/detonation (only for one dyno run, don't worry)...

 

[CobraKindaGuy]

Originally posted by caveman6666
They actually told you that a chip and pulley were 'warranty friendly' mods?

I don't think what he said is meant that way...I think he meant that SVT expected us to make the mods he listed so the car was designed and tested to hold up to the stress that those particular mods would create on the car. Beyond those mods listed SVT cannot say the car would hold up. It has nothing to do with those mods being "warranty friendly".

 

[caveman6666]

Originally posted by CobraKindaGuy
I don't think what he said is meant that way...I think he meant that SVT expected us to make the mods he listed so the car was designed and tested to hold up to the stress that those particular mods would create on the car. Beyond those mods listed SVT cannot say the car would hold up. It has nothing to do with those mods being "warranty friendly".

What he said:
>>They figured we wouldn't be able to leave it alone so. They expected us to:

1. CAI or K&N
2. exhaust
3. Lightning pulley (2.93)
4. Chip

Everything past that they said your "on your own"<<


"On your own" would seem to mean that up until that point, you're covered.

 

[Quadcammer]

please do not put 10.2 to 1 compression pistons on your eaton cobra. that is just a flat out bad idea.

as for a set of pistons, most run 700 to 800 with rings. then add a bore/hone, balancing, bearings, head gasket, assembly, additional labor etc.

it adds up very fast.

 

[orange2004cobra]

Higher octane burns cooler, and slower..
Thats why race fuel helps against etonation...
Lower octane burne faster and hotter..
L.

 

[Black2003Cobra]

This is a good discussion. A few people have really hit the nail on the head, in my opinion. The bottom line is, as you add more and more stress on the engine, its life span will get shorter and shorter. That is the basic tradeoff. And as some have eluded to, it really doesn't matter how you stress it. A higher boosted car that doesn't have the snot beaten out of it every weekend can last longer than one with a less boost that is driven much harder. In other words, the effects of stress are cummulative.