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Discussion Starter · #1 ·
Ok since I cant wait untill monday to call KB I thought I might ask here since i know some others have KB superchargers, and might have run into some these issues.

From what I understand if you have a 9psi kit the only thing you need to upgrade to 14 psi is the pully. The tune you get form KB was intended to cover you form 9-14 psi.

Now what if you drop in a new block with 8.5 compression and a lil more stroke? How much will that affect the tune?

The reason I am asking is I am tryen to avoid a dyno tune on a new block. I would rather braek it in easy before I throw it on a dyno and start running it to redline.
 

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Well first of all who told you that the K-B tune for the 9psi kit is good to 14psi?
I have the 9psikit with the K-B tune making 380 to 385rwhp, some have made up to 405rwhp with that tune.
That figures out to around 440at the crank.
And at that Jim Bell told me that that was pretty much at the max limit for the stock bottom end.
I just did an 03 cobra block last spring at 20 over with 18cc dished pistons using the cobra crank and rods. with my 1.7L K-B and a 15psi pulley it should make around 455 to 465 at the wheels. I did not get it completed in time to do a full dyno tune before storage this winter. But what pulls were made it was well above 410 and running out of fuel.
So to be safe with the stock bottom i would not go above the 9psi pulley because you can get detonation and that if you dnot hear it can lead to real problems.
As far as the tune being good to 14psi i really dont think so or bell would have said.
If you have any other Qs feel free to PM me and i will help in any way.
My son has a HIPO mustang shop and builds and tunes these cars everyday and is also the K-B dealer in minnesota.
 

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^ what he said. an increase of 5lbs of boost is a dramatic increase in relation to a tune.
 

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Discussion Starter · #4 ·
Actualy in KB's FAQ they only claim 11 psi with 94 octane without changing the tune. I read in a couple tech articals that are posted on KB's web page that lead me to think the tune was good to 14psi. In both "To Screw or Not to Screw" and "Besting Big Brother" they ran a stock GT block to 14-15 psi with Jim Bell riding shotgun both times. They used race fuel to do it but it was a stock GT kicken out over 500rwhp. In the tech artical "Snake Skinning" also posted right along with the others they not only ran a stock GT at 14psi they clearly stated in the last couple lines that 14 pounds of boost and 500 hp is yours for the price of a blower pulley.

I am not tryen to bust your balls, just wanted you to know where I get my ideas. I am not going into how long a stock block can make that kind of power or any of that crap cuz I dont care. I am no longer dealing with a stock block.

I guess I asked the wrong question. What I really want to know is if i can bolt up my KB 2.1L blower with the 9psi pulley to my new block thats stroked and has 8.5 compression with out getting a new tune. Just so I can break it in before tuning.
 

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a custom dyno tune from a reputable shop is the best way to go regardless
 

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Right now am using the 36s that came with my kit but will be switching to 42s.
I guess i miss understood the Q that you were asking.
Did not know that you had the 2.1 kit so that does make a difference.

To answer your Q,yes you can break in the motor before a new tune, I put around 1100 miles on mine with the original K-B tune before going to the dyno.
Was careful not to romp on it hard and keep it below redline.
Just make sure it has good gas in the tank.
I hope this helps.
BTW it wasnt a dumb Q.
 

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AzRael said:
Thats just what I said I was tryen to avoid on a new block. I just dont want it broke in that way.
well obviously, you put your breakin mileage on it staying below a certain rpm, then when she's got enough mileage and new oil run through it then you take it to the dyno.....if your babying the car around your never gonna see 14lbs so it won't be an issue
 

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Discussion Starter · #11 ·
Update

Ok I got the new stroked engine installed. I have been keeping it under 4k rpm and no more than 1/2 to 3/4 throttle for all my little tests. I screwed up and gaped all the plugs to .054 and didn't find out until today they should have been gaped to .035. I think the boosta spark is the only thing that keeps it running. I left the 9 psi pulley the kb came with on, but installed a 6.6" dampener. Using my wide band af meter it runs around 15 - 16:1 at idle, 14.5 - 15:1 during light acceleration and cruise, and 10 - 13:1 during boost regardless of the amount of boost it gets. With the 9psi pulley it would hit 7psi at 1/2 - 3/4 throttle. After running a week like this I thought I would try the 2 3/8s pulley that kb said should put me around 16psi thinking it might even out the rich condition during boost. I was wrong, the af meter reads exactly the same as with the 9psi pulley this was confirmed by my friends diablo tuner run before and after the pulley change, using some function that I know nothing about. I just let him run it while I drove. BUT I kept it around 10psi and not any more than 1/2 - 3/4 throttle. The one time I went over 10 psi was when some ricer tried to do a 50 mph fly-by. He didn't make it but the car sputtered a little when it hit 15psi. I think it was the plug gap that I plan to fix after work. Car gets tuned the 5th May in Tulsa. I was looking to get over 600 hp but I think I am gonna get let down ...Will see on the 5th
 

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What shop is doing the tune? I would love to see your car. Do you live near Tulsa?
 

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Give me a shout when you head up this way I will try to meet you over there. Have you talked to SW Tuning in OKC, the owner has a Bullitt.

Thanks for the compliments on the paint job. Wish I could take credit for it, but the previous owner had it done.
 

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Discussion Starter · #15 ·
My friend is taking his GT to SW Tuning Monday afternoon. I talked to the guy there. I didn't like his attitude. Seemed a little full of himself. Nothing wrong with being a little cocky, but to repeat 5-6 times "I'm not cheap" in a short conversation like he is really to good to even look at my car kind of rubbed me the wrong way. KB recommended Archangel. I had never heard of them before.

BTW regaped the plugs to .035 and it fixed the sputter at 15psi boost
 
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