Super Low HP #s for a Kenne Bell 1.5 Superchared 347

[Marine4u123]

I have the 1.5 series Kenne Bell with the blowzilla intake and bypass on a 347 stroker. Not making the power I thought I would be making. It's still at the shop and I'm picking it up tomorrow. They say it's going to be around 300rwhp, but i'm thinking that's low even with a chip i'm getting. They think the blower is restricting the motor. I have the 9lb pulley, but it's only making 5lbs of boost. I think the belt is not on correctly. The belt from the air compressor running directly to the blower pulley and from the blower pulley to the idler pulley to the tensioner. This belt path that i'm mentioning is going from right to left if you were standing in front of the car I will find out tomorrow. The list of mods are AFR 185 heads, gt 40 lower intake, 42 lbs injector 75 mm accufab tb, 80 mm mass air, fuel pressure regulator, msd distributor, msd 6al, 255 inline and 255 intake fuel pump. 214/ .533 /.533 cam specs, 1.6 roller rockers, no FMU, stock fuel rails. They said with no timming in made around 270rwhp and 383rwtq. I nearly died when I heard those numbers. The compression is 8:1 I'm wondering if the car will make more hp naturally and not use the kb blower? I'll update you on what's going on. Anyone else feel free to reply.

 

[shiz302]

You should make more, I can imagine you losing a few psi because of the free flowing heads and intake, but 4psi? Boost is boost and you should see at least 330rwhp on motor. IMO

what shop?

 

[93Cobra#2771]

Something is not right, and the blower isn't restricting your motor. The motor itself should make close to 300 n/a (even with the low compression you are running). The motor would be a slug with the low compression and a blower, IMHO.

Belt slippage? Pig rich a/f? What kind of exhaust are you running?

 

[Speedfreek]

I have nearly the same setup but a 331 and a vortech making 8psi, and it dyno'd in at 524hp and 510tq. They must have your car way out of tune.Mine was way out of tune and the hp was 396 and tq was 486. Tq was 100 more untuned, they tuned it and got the hp up by 130 or so and the tq up by 24. So maybe your car is out of tune as bad as mine was.

 

[Speedfreek]

Yea and check the belt for slipage as well.

 

[93Cobra#2771]

A bad or miscalibrated MAF could cause a major HP loss as well...

 

[lxboy]

as far outa tune as it is even with the belt slipping with the 4 psi he is seeing it shoule be way more than 300rwhp somethin is very wrong man. Is there detination what is total timing. Did you check comopression on the cylinders?\


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[lxboy]

there is a guy on this site with a 347 and a kenne bell that makes 480rwhp and 502ftlbs on a very conservitive tune and 6-8lbs of boost.

 

[Marine4u123]

They got 316rwhp and 383 rwtq. Better numbers than before but still sux a$$. :mj: :shrug: Just got off the phone with them. Quick conversation b/c I'm going over there now. I have 1 5/8 long tube headers and matching hpipe (both bbk). I have 1chamber flowmasters that dump out to the middle of the car (doesn't go all the way to the back) w/ 3 inch inlet and outlet. I also think there is major belt slipage or put on incorrectly. I'll update you guys tonight. It already has a tune and chipped. Not sure what timing they have but I'll find out. Remember I have a 9 lb pulley on there and it's only making 5 lbs of boost. :shrug: Thanks everyone for your help.

 

[LEE93COBRA]

When pulleys are rated they are based off stock motors. A 9psi pulley on a AFR 185 'headed' 8:1 stroker motor is probably going to only equal 5 psi of boost. You need to put around an 18 psi pulley on the car (if they make one that high) to see around 10-11 psi of boost. For example, my car is pullied for a 20psi on a stock 302. On my AFR 165'd Cobra 302 I only saw 14psi of boost.

Also, your 8:1 compression ratio is killing you on power. Just that 1 point in compression drop is worth around 75-80rwhp. You 'might' be able to get your tuner to add some more total timing in the car and get more power. I agree with everyone else though, your tune is way off somewhere. What's the a/f? What MAF and injector size are you running?

 

[93Cobra#2771]

Also, your 8:1 compression ratio is killing you on power.

I was thinking the same thing, Lee. Why the super low compression? Heck, you could prob run 20+psi through a motor with that low of a compression (assuming the motor was up to the power levels).

And, if the cam has too much overlap for the blower, that will drop your psi as well. Too much overlap on a blower car really hurts power.

 

[LEE93COBRA]

Yeah, a friend and I learned the hardway a couple of weeks ago when we took his car to get tuned. Its a 96 Cobra, forged rotating assembly (dropped compression from 10:1 to 8.8:1), with a Vortech S-trim.

This car bone stock plus a 14 psi (actual boost) S-trim put down 523 rwhp/420 rwtq. With the lower compression motor and 16psi boost the car went down to 455 rwhp 400 rwtq. That's right 1.2 or so point drop in compression + 2 more psi ='s almost 75 rwhp less than before. No other changes were done to the car. Just think if he was still on the 14psi pulley, he would be close to 100 rwhp loss just because of the compression ratio drop.

 

[93Cobra#2771]

Oh well, time to upgrade blowers!

 

[Marine4u123]

You're right guys, The blower is what's keeping me from making any kind of HP. The blower was meant for stock mustang applications or lightly modded stock engines. It's a 1.5L Kenne bell. The car screams in the begining then it sounds like it's calling for more air at higher rpms. The other blower which I've been told that works better is the Kenne bell 2.2L for engines with bigger "displacement" i.e. 347 351 etc. I will be selling my Kenne bell and go with a Vortech or Prochager. The max pully on my current supercharger is 9 lbs of boost. Dispite my low HP numbers my car is a blast to drive. The last time I drove my car it was completely stock! The A/F is pegged at rich, and I believe the timing is at 14. Thank you everyone for helping me out in this situation. Oh by the way the belt is on correctly and there is no slippage. I chose the Kenne bell 1.5 b/c I was going to put it in my stock motor. The day before I was going to put the blower on the motor die on me so I decided it was a good time to rebuild it to a 347 stroker. I hope someone reading this can learn from my situation and not make my mistake. When I get my new supercharger I'll give ya'll some better numbers hopefully. :bash:

 

[sled]

I have nearly the same setup but a 331 and a vortech making 8psi, and it dyno'd in at 524hp and 510tq. They must have your car way out of tune.Mine was way out of tune and the hp was 396 and tq was 486. Tq was 100 more untuned, they tuned it and got the hp up by 130 or so and the tq up by 24. So maybe your car is out of tune as bad as mine was.

hey what are the specs on your motor. heads, cam, intake, and C.R.
thanks

 

[93Snake]

why not go with the 2.2 KB :-D ? I love the feel of twin screw on the street.. just some more food for thought

 

[Marine4u123]

The 2.2 is out of my budget right now. I guess I can sell my 1.5 then save up for the 2.2. I have all winter to think about it. It's snowing like hell here in NYC!!! :fm: