Stock bottom end, boosted, suggested redline for Dyno pull?

[Skips]

Hey folks. I have a stock bottom end with a novi 2200sl long tubes and catless . Gonna do a dyno pull in the near future . What what have others used that were boosted with stock bottom ends use for rev limiter setting on their dyno Pull? Right now I have my red line set low (6075) for longevity but for that one pull I have no problem turning it up I just don't know what a good number is.

 

[Pentalab]

Hey folks. I have a stock bottom end with a novi 2200sl long tubes and catless . Gonna do a dyno pull in the near future . What what have others used that were boosted with stock bottom ends use for rev limiter setting on their dyno Pull? Right now I have my red line set low (6075) for longevity but for that one pull I have no problem turning it up I just don't know what a good number is.

My oem 2010 GT was factory set to 6250 rpm. VMP increased it to 6500 rpm (Roush M90 installed). The X3 tuner I got from VMP allowed me to tweak the rev limiter... BUT only in coarse increments. The next step down from 6500 rpm is 6250 rpm, so I put it back to 6250 rpm.

VMP and other tuners typ say the stock bottom end is good for 6500 rpm...with boost. How much boost, I forget.

I would not go much above 6250 rpm. Then shift at 6k max. Better to be safe than sorry. The oem rods in the 4.6L 2005-2010 cars are pretzel sticks.

 

[Dino Dino Bambino]

Hey folks. I have a stock bottom end with a novi 2200sl long tubes and catless . Gonna do a dyno pull in the near future . What what have others used that were boosted with stock bottom ends use for rev limiter setting on their dyno Pull? Right now I have my red line set low (6075) for longevity but for that one pull I have no problem turning it up I just don't know what a good number is.

I know Brenspeed have done dyno pulls on boosted stock bottom end 3Vs as high as 6700rpm but I'd suggest a more cautious 6500rpm as a safe limit since you're likely to hit peak HP on the dyno by then.
Brenspeed recommends a limit of about 450rwtq on stock connecting rods. Though maximum boost with the Paxton Novi 2200SL is likely to be about 10psi at 6500rpm, it'll be a more conservative 5-7psi at 4500-5500rpm where the torque curve will peak, and that'll be fine.

 

[JC SSP]

I would stick with your current limiter. Watch the dyno and see if it continues to build power past that rpm. If it does then you know you can raise it and make more power…

 

[RocketcarX]

I would spin the stock bottom end to 7k without a second though. It won't pop and you can see what your powerband really is.

 

[AHaze]

Stock bottom end with a Vortech Si here and my rev limiter has been set to 6500 for 2 years (and regularly approached, I might add).

 

[Dino Dino Bambino]

 

[Pentalab]

I would spin the stock bottom end to 7k without a second though. It won't pop and you can see what your powerband really is.

Are u sure abt this ?

 

[RocketcarX]

Are u sure abt this ?

200lbs of nitrous followed by 2 years of dedicated road course use in a stock internal R&D rig says if you can tune worth a flip the 3v is tough as anything else. 7k is 200 rpm higher that Ford specs with stock springs and the Hot Rod cams. It will be fine.
There are hundreds of these things doing just that. 3 dyno pulls aren't going to hurt anything.

 

[Candy10]

See my profile pic. That’s a stock rod hanging out of my stock block. Kenne Bell @ 10psi revved to 6500.be conservative, redline power doesn’t really mean shit anyway

 

[AHaze]

redline power doesn’t really mean shit anyway

It certainly does with a centrifugal and a TR3650. Making the 1-2 shift at 6000 RPM drops you down to 3550 RPM and well below the meaty part of the power band. Moving the shift point up to 6500 still isn't really enough but I dare not go any higher.

 

[Pentalab]

A PD blower gives you the instant TQ hit. The story I got was the force on the rods goes up to the square of the rpm. Then I also heard the force on the rods goes up to the cube of the rpm. If you do the maths, > 6500 rpm is pushing your luck. Window the block, and your day is done.

Plenty of FRPP setups with the 11 psi boost setups that have windowed the block. Their lower 9 psi setups fared a bit better. Those are both PD blowers. Even the cops had a modified mustang for hwy use, with the 11 psi FRPP setup, and they windowed the block. It did not last very long either.

Typ, on a centrifugal, the boost goes up to the square of the rpm, so I can see wanting to shift higher.

On my 2010 GT, it's a 5r55s automatic, and 2nd gear in the 5r55s is 14% lower than 2nd gear in the TR3650. 3rd gear in the 5r55s is 16.5% lower than 3rd gear in the TR3650. Where I lose it, is when shifting from 3-4 at 6 krpm, then it drops to just 3500 rpm.

 

[Dino Dino Bambino]

See my profile pic. That’s a stock rod hanging out of my stock block. Kenne Bell @ 10psi revved to 6500.be conservative, redline power doesn’t really mean shit anyway

A boost of 10psi from a PD blower would have taken you way above the 450rwtq limit recommended by Brenspeed so it wouldn't have mattered how high you revved the engine. The stock I beam rods will bend if the cylinder pressure is too high (hence maximum torque rather than HP is the limiting factor) 'cause they weren't designed for boosted applications in the first place.
I'd recommend maximum boost of 7psi from a PD blower or turbo on a stock bottom end. A centrifugal such as the popular Paxton NOVI 2200SL will typically produce 5-7psi of boost in the 4500-5500rpm maximum torque range. Even though it makes maximum boost of 10psi at 6500rpm, it's still OK but I wouldn't rev the engine any higher than that.
A centrifugal is usually more forgiving on the engine and drivetrain since boost builds in proportion with rpm squared and the power delivery is more linear without the big hit of boost in the midrange.

 

[RocketcarX]

There is way too much secondhand knowledge in this post. If you aren't building or tuning these cars lets try to save 15-year-old parroted advice from defunct vendors for Facebook.
This is why the forums are dying

 

[moooosestang]

The engine isn't going to make much or any more power past 6200rpms. Mine is set at 6600 and my shift light set to 6200. it really feels flat past 6k on the butt dyno. That's running 11psi with a whipple though.

 

[AHaze]

The engine isn't going to make much or any more power past 6200rpms. Mine is set at 6600 and my shift light set to 6200. it really feels flat past 6k on the butt dyno. That's running 11psi with a whipple though.

Not the case at all with a centrifugal.
This is the first dyno graph I could find for a 3V with a centri. As you can see, power is still rising sharply when they shut it down at 6200. Even the stock line (blue) isn't exactly dropping off a cliff at 6k and it seems pretty reasonable to hang on to first for a few hundred extra RPM.
View media item 8838

 

[Candy10]

It certainly does with a centrifugal and a TR3650. Making the 1-2 shift at 6000 RPM drops you down to 3550 RPM and well below the meaty part of the power band. Moving the shift point up to 6500 still isn't really enough but I dare not go any higher.

While that is true, I was basing my response on the title of the thread. Dyno run vs shift points for maximum performance