Kenne Bell Questions...

[Rickyll7]

My car has lowered compression and is a stroker, so it behaves a lot different than a stock short block so I cant tell you exactly what timing will work with your car as I've only tuned my car.

If it were me, I would just get 2 tunes, one for 91 and one for race fuel. You should be covered with that anywhere you go unless you go overseas to some place that has only less than 91 octane. I don't know of any places like that, but you could get a 89 octane tune just in case.

You should know that to get a tune for a certain octane fuel, you need to have that fuel in the tank while the tune is being done. Otherwise, it could knock with that fuel and you wouldn't know until you put that fuel in it.

I would stick with the general guidelines from KB and start with the base tunes given by SCT for 91 octane and race gas for blown PI 2v modulars.

 

[usaf_branham]

Thanks for the heads up man, do you know of any other tuners in this forum that have experience with kenne bell's? I know what kenne bell says, but i like to take other oppinions in to consideration as well.

I am envious, i want to build my bottom end and throw the trickflow heads on it with some stage 3 cams, although, i think would actually go with approx 9.5 cr since im limited to 14 psi with the 2.1

 

[Rickyll7]

No names come to mind at the moment, but I bet you could find a few by searching for prp or pro racer package in the forum.

 

[trinity_gt]

I am envious, i want to build my bottom end and throw the trickflow heads on it with some stage 3 cams, although, i think would actually go with approx 9.5 cr since im limited to 14 psi with the 2.1

Bigger is definitely not always better with a blower. "Stage 3" -- whatever that is -- likely has way too much overlap to be really effective with a PD blower.

 

[Rickyll7]

Bigger is definitely not always better with a blower. "Stage 3" -- whatever that is -- likely has way too much overlap to be really effective with a PD blower.

There are plenty of stage 3 blower cams out there.

 

[Rickyll7]

Thanks for the heads up man, do you know of any other tuners in this forum that have experience with kenne bell's? I know what kenne bell says, but i like to take other oppinions in to consideration as well.

I am envious, i want to build my bottom end and throw the trickflow heads on it with some stage 3 cams, although, i think would actually go with approx 9.5 cr since im limited to 14 psi with the 2.1

You aren't limited to 14 psi with that blower. The limits of that blower come in the form of either over revving the blower or out flowing the inlet and throttle body.

Kenne Bell says the losses of the inlet become significant at around 500 rwhp. At that point, you could always upgrade the inlet if you still have more blower speed left. Tim from MPH has something, I think, that would work. Or you could buy a used 2.6-2.8 kb inlet from someone who upgraded to Tim's piece.

 

[trinity_gt]

There are plenty of stage 3 blower cams out there.

Since there's no set definition for what constitutes the various "stages" of cams I will stand by my statement: Just as it's possible with a N/A car, it's possible to go too big on a cam in a blower car and end up hurting overall area under the power curve and the torque characteristic.

For a street-driven car, a "stage 3" cam might sound all lumpy and cool at idle but the penalty is usually reduced low RPM output and efficiency.

The OPer would need to select his components carefully to match his combo to his expected driving situations remembering that bigger is not always better.

 

[Rickyll7]

True.

 

[usaf_branham]

Bigger isnt always better, especially with cams on a street car.

 

[usaf_branham]

I prefer the lumpy idle and I get the differences between a mild street cam and a 'stage 3 blower cam'... I will sacrifice my low end rpm for a nasty powerband between 3k and 7k

 

[trinity_gt]

I prefer the lumpy idle and I get the differences between a mild street cam and a 'stage 3 blower cam'... I will sacrifice my low end rpm for a nasty powerband between 3k and 7k

Fair enough. It's your car.

Out of curiosity, how much time, as a percentage, will this car spend at 7000RPM versus, say, at 1500-3000RPM? Is this a daily driver? A track-only car? A car that sees dual duty?

As well, if you want 7000 RPM out of it, you'll need to think about the blower RPM. Check with KB but I believe they've got a limit of ~18000RPM on the rotors. To limit the rotor speed at 7000RPM crank speed you're probably going to have to muck around with pulley sizes. This will limit boost.

Perhaps for a kabillion RPM engine you should be thinking about turbos instead of a PD blower...

 

[Rickyll7]

For the stock crank pulley (6-1/2 inch) and a 2-5/8 inch blower pulley, you will spin the blower at 17,333 rpm when the engine is at 7k rpm. A 2-5/8 inch pulley will get plenty of boost on a 4.6. I'm running a 2-7/8 inch pulley now and I get about 9-9.5psi, even with my stroker and other mods that lower boost. A 2-3/4 inch pulley should get me about 11-12 psi and a 2-5/8 should get me about 13-14 psi.

One could even keep going from there if they didn't spin as high as 7k and dealt with belt splip with an 8-rib setup (belt slip will eventualy happen). One could make as much as 17-18 psi with a 2-3/8 inch pulley (may require a bigger inlet and throttle body). They could even spin the engine as high as 6500 and still stay below the 18,000 rpm blower limit with the 2-3/8 inch pulley.

The 2.1 makes more boost than a 1.7 with the same blower speed.

http://kennebell.net/techinfo/ford-techinfo/46gtTechTips.pdf