Boost/Power Limitation on STOCK motor...

[2SIKGT]

just curious as to what the boost limitations are on a stock motor. 20psi? 22psi?

how much power do the stock motors handle? crank and wheel hp, before problems start...and where?

where to problems start to begins?

~45k miles, 2.9 whipple, e85

thanks in advance guys! :beer:

 

[cobracide]

Octane, timing.

 

[SVT Pille]

With E-85 you can run the stock motor to around 21-22psi and 750rwhp seems to be the limit on the stock long block with the right tuning.

For 93 octane I wouldn't push it past 18/19 psi, anything over 700rwhp on pump gas is asking for problems imo.

 

[Nickerz]

650rwhp is generally the safe limit quoted. Getting some nice pistons can go a long way.

 

[Sonic605hp]

Tune has a huge impact. There are many stock motor cars deep into the 600rwhp range and above.

 

[Nickerz]

A lot of this reminds me of the Supra guys. They all like to claim the cars are indestructible, but more and more people have figured out there are in fact much lower limits at a practical level than has been advertised.

Most of the big power guys back in the days ran Supra shops. What are they going to be posting every time they lose a motor? No, of course not. A lot of the Cobra guys are the same way, they run 700rwhp pump gas stock short blocks for a while, then they lose it with all the right parts and the right tune.

At 600rwhp you are already approaching twice the factory rated support, which in general is a good rule of thumb. I've read several people's replies that have worked at places like Tremec or Ford, and they in general engineer for twice the output or mileage they're trying to hit. So I don't think its a coincidence that 650rwhp seems to be a pretty solid number given the 385hp factory rating which comes out to ~770 at the flywheel for that double safety margin.

I think being realistic and a little bit cautious is always a good approach unless you don't mind spending large amount of money when stuff blows up.

I think there is a lot of ungiven respect to the engineering teams behind this car. People like think they've figured out what ford hasn't by saying "oh, so and so is doing 1000rwhp on the stock block! 750rwho is no big deal!"

I can assure you the guys at Ford knew exactly what this block could handle, and given the numbers its probably a pretty solid 650rwhp for at least 36K miles given a number of posts on the topic.

 

[cbr repsol]

I think u can get away with a bit more with turbos, 800 rwhp no prob . I think lethalvnms car was around 800 rwhp on e85 & nitrous on the stock motor,With 25 deg timing. Im sure it really benifited from the cooling effects of e85 . So I thing everyones car is different , still anything with that much power is on borrowed time. Mm&ff did the hellion hellraisor kit and was running something nasty like 1200 hp at the crank and I heard it blew in a month. (not sure of that ,just what I heard)

 

[01cobravortech]

These longblocks can handle a lot of power but how long will it live? Lots of guys out there with 650 and above, but not a whole lot of miles on those motors. I'd like to see 650 and above on +100k longblocks.

 

[2SIKGT]

ttt

 

[Jimmysidecarr]

533rwhp


Appears to be very trouble free, I'm thinking about doing a 3.25" upper and one of these:
http://www.svtperformance.com/forum...rries-j-s-safeguard-knock-control-system.html

 

[CobraBob]

Good one Jimmy!

 

[2SIKGT]

533rwhp


Appears to be very trouble free, I'm thinking about doing a 3.25" upper and one of these:
http://www.svtperformance.com/forum...rries-j-s-safeguard-knock-control-system.html

what exactly is that? :shrug:

 

[younggun04]

I have been at 600 RWHP for about 4 years now, No issues. Car runs so good I decided to put a turbo on it and go for 700+!

 

[earico]

533rwhp


Appears to be very trouble free, I'm thinking about doing a 3.25" upper and one of these:
http://www.svtperformance.com/forum...rries-j-s-safeguard-knock-control-system.html

Say it ain't so. Lol. Jimmys changing the pulley on his Whipple? I'm speechless. :rockon: :beer:

 

[Jimmysidecarr]

what exactly is that? :shrug:

Mods list in link of sig. --> 2.3L Whipple 3.50 pulley.

 

[DSG2NV03]

what exactly is that? :shrug:

I think he means the Vampire. It is a system that detects knock in your engine and I believe it can either pull timing in that particular cylinder or the entire engine thus saving your engine.

 

[Jimmysidecarr]

I think he means the Vampire. It is a system that detects knock in your engine and I believe it can either pull timing in that particular cylinder or the entire engine thus saving your engine.

Can you imagine if that technology actually came on these when new?

These car would have been referred to as BOMB PROOF!:rockon:

 

[D-Con]

Mods list in link of sig. --> 2.3L Whipple 3.50 pulley.

The only 3.5 Whipple pulley that's been used for more than 3-days!

I'm on a 3.1" pulley and just bought the vampire with thoughts of either getting more aggressive on the tune and/or going to a 3.0 or smaller . Probably just use it to get the tune more optimized without worrying about a tank of bad gas or something else going awry.

The best part about the vampire is that the gauge will tell when the tune is too agggressive and the base-map for each cylinder can then be adjusted for no knock. After the tune, the protection is still there if something happens to cause spark knock.

Too much fuel is often used to prevent spark knock, at least some tuners say that is bad as the extra fuel ends up in the ring lands and results in combustion there. That's not good for a long life despite the extra fuel preventing the knock.

 

[DSG2NV03]

Can you imagine if that technology actually came on these when new?

These car would have been referred to as BOMB PROOF!:rockon:

No kidding Jimmy. More stuff I have to save for!:beer:

 

[Co-brat]

I have read and been told by some tuners that these motors will SURVIVE at 650rwhp reliably but beyond that the the factory tolerences begin to get iffy and you will be pushing your luck. I think the pistons and factory ring gap clearences are the weak links in these bottom ends.