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Discussion Starter · #1 ·
I'm running a KB at 16# on my stock block and even with more part throttle timing it does not hit as hard as when I had my unported eaton at the same boost. Is that an inherent trait with a KB or that design blower? Should I be looking at potential other issues? I have the supporting mods such as MAF, fuel pumps and injectors, but I'm actually dissapointed. The KB does pull harder at WOT, but other than that it leaves a bit to be desired.....at least at 16#. Part throttle was better with my Eaton.
 

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I've said the same thing. When I had my kb rebuilt, I installed my ported eaton and everything I thought was because of the cams was from the blower. Makes me rethink a lot of things since I mostly see street duty.
 

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99 problems and $$ is all of em
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no experience with the kb but i would imagine at any throttle level the kb should easily outshine the eaton in every way. what spark plug/gap you running? throttle body? big plenum? we need a little info on your truck. could be intercooler pump not working, bad tune, anything. did you even get retuned after the kb install?
 

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Discussion Starter · #4 ·
Same tuner for both the KB an Eaton tune. Both were tuned on the same dyne. KB has an Accufab throttbody. Intercooler pump is fine, I've datalogged it in real time. I've had my tuner add more part throttle timing
 

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Well I do have both and the kb isn't the best down low no matter what. That, is why there is a difference in blOwers. One is a roots and the other is twin screw, the roots Produces way more bottom end and response vs twin screw. Like you said, the kb has top end where guys like to see big numbers.
It really pisses me off sometimes but messing with low end timing helps out.
 

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99 problems and $$ is all of em
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there should be a little difference down low but it shouldnt be a dog off the line. who does your tuning?
 

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Discussion Starter · #7 ·
I just felt like I should have more response than I currently have at part throttle. Where is the point where there is too much part throttle timing? Is there a point where it starts to effect the wot timing tables? I had my tuner add a couple degrees more timing at part throttle. I still feel it needs more.
 

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99 problems and $$ is all of em
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ill ask again: who does your tuning? you might need a new tuner.
 

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The Eaton bypass valve starts closing at about 8" of vacuum and the Eaton is significantly helping part throttle power by the time you reach 5" of vacuum because you are probly overdriving it a lot. The new KB bypass valves are completely open until about 1.5" of vacuum and you are probly not spinning it as fast so the power feels down by comparison to the until the bypass valve closes. Just give it enough throttle to close the bypass valve and there is no comparison.

FWIW the KB is a lot easier to drive for me about 5 months a year when the roads are covered with a few inches of solid ice.
 

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Discussion Starter · #10 ·
That is a good explanation and having driven it for a few months now that explains a good portion of it. I would have to say it's more of a response issue than lack of power for me. I guess by adding more timing it's seemingly making up for the slower response; of course it's all within fractions of a second.
 

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When I went from a Ported Eaton to a 2.6 KB on my 99 I picked up @ 80/90 to the rear wheels and the KB was CLEARLY faster and more responsive at any throttle position.

This is the original comparison with no changes other than swapping the SC



No where on that chart did the Eaton have an advantage, I'd say something is not correct in your case

PS
Later the tuner tweaked it to 594/695 for a safe low octane street tune.
 

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Mr. Crossfire
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Becareful on adding timing on your stock block
 

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I have the baby brother to your 2.6 Kenne Bell,the 2.3 Kenne Bell and it makes more power than my 6lb/9.00" Eaton combination at any throttle position. Stock Long Block spinning the 2.3 Kenne Bell slower with a 3.25" upper. You have other issues some where.

:smt102-Bob
 

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Fat Bastad
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This is how KB tech Mike explained it to me.

A lot of you guys that were around back then will remember when I went through this ordeal.

It would also depend on the cams installed in the truck (stock vs aftermarket) and which generation bypass actuator was on the KB as well. The original KB's bypass actuators were designed to work (close the bypss valve) @ 15 (mmHg or mmH20???) of vacuum meaning that anything below that the SC was in the boost (valve closed) and the newer version bypass actuator was redesigned to function at a much lower vacuum of around 5 psi which means that at when at cruising speed the SC required much less throttle for the SC to begin producing boost (close the bypass valve) and depending on the specific aftermarket cam might even be producing boost at all times while cruising at highway speeds due to the much lower vacuum (aftermarket~9 vs stock >15) that certain aftermarket cams produce when at highway cruising speeds.



Here is some good news for some of you stock cammed guys running KB SC's...:rockon_ford

Your truck can benefit by getting your hands on one of KB's original bypass actuators. Here's how...

Old bypass actuator designed to engage boost at around 15 or above
New bypass actuator designed to engage at around 5 or above.

Aftermarket cams + old style boost actuator= Boost response is much quicker and often is always in the boost which produces excessive heat that baked and quickly cracked the seals. This is the reason that KB had problems with their seals going bad not long ago. They would bake due to the constand boost producing excessive heat and then crack which allowed the SC oil to escape into the intake and require new seals on a relatively young supercharger. The truck had a much quicker response but the seals weren't lasting.

Stock cams + new actuator (red cap)= Boost response not as quick to engage. SC functioning properly at highway speeds and no more problems with their seals getting baked, cracking, SC leaking oil into the intake and requiring repair.

KB now sends out all of their SC's with the newer red cap actuators as a result of so many seals going bad. This is actually a disadvantage to those guys that are running KB superchargers and stock cams. Those guys would benefit from a quicker response from their superchargers with the old original (no red cap) boost bypass actuators.

I think I got all of that right but it was a long time ago that I spoke to KB about all of that so please don't take what I've said here as the gospel. Please confirm with KB if you're wanting to mount up one of the old actuators to your stock cammed truck before doing so to make sure what I've said here is in fact completely accurate or not but I'm pretty sure that it is.


Here is a link to an old thread that KB chimed in on when I was having problems with what was a relatively new unit which was completely rebuilt at KB and then shipped to me from the guy I purchased it from.

http://www.lightningrodder.com/forum/showthread.php?t=39704




The supercharger worked fantastic when first put onto the truck with an amazing throttle response but in less than 4-5 months I'd say began blowing smoke from the tail pipe due to the unit having the old actuator on it. A sure indicator that your seals need replaced.



Roach
 

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Worlds Fastest Street HD Truck
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The Eaton bypass valve starts closing at about 8" of vacuum and the Eaton is significantly helping part throttle power by the time you reach 5" of vacuum because you are probly overdriving it a lot. The new KB bypass valves are completely open until about 1.5" of vacuum and you are probly not spinning it as fast so the power feels down by comparison to the until the bypass valve closes. Just give it enough throttle to close the bypass valve and there is no comparison.

FWIW the KB is a lot easier to drive for me about 5 months a year when the roads are covered with a few inches of solid ice.
BINGO!

I'm betting you've got a newer bypass valve on your KB. I bought my KB in '08 so it had the original style. That shut the bypass valve with still several inches of vacuum, and holy shiznit the truck would light the tires up with a tap of the throttle because with big cams, the truck has less vacuum than a stock head/cam setup. Absolutely retarded driving, I loved it. BUT, it causes high IAT temps that can cause a lockup. The newer bypass valves don't have a spring so they keep it in bypass till you're almost out of vacuum. This keeps IAT's much lower (you don't want to be cruising with the bypass shut!). When I removed the spring in my bypass valve, it felt like I lost 100 hp down low because it wouldn't fly into boost with the silghtly tap of the throttle. Really the powers the same once I'm on the pedal, and just "normal/sane" when I'm lightly driving, and better for the blower.

Do you have stock heads/cams? If so, you could probably still use the orignial style bypass since you should have pretty strong vacuum still, so it shouldn't be an IAT2 issue since cruising you should have good vacuum and the original style with the spring will still allow bypass.

You can do a quick test of how it'll feel by unplugging the bypass valve. That will keep the valve shut, and you'll get instant boost. Feel how different it drives and let us know if the truck has that responsiveness back. Just don't keep it that way, but it's fine to do for a test around the block.

If that's the case, and you are on stock heads/cams, i'd see about getting an original style bypass with the spring if you have the low vacuum version.
 

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4x4 lift
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What these guys said ^

I switched over to a 2.3 kb with a newer accuator.
Doesn't feel weaker than the eaton, a little bit stronger at partial throttle, but still made me go wtf.
Still running stock cams/heads, so it takes a bit for the accuator to close.
 

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lol me and roach were typing away at the same time. Anybody clicking and just seeing the 2nd page with my post, go back and read Roach's, his says essentially the same thing but a bit clearer and with more detail.


I probably still have my spring from my actuator if somebody needed to add it back in. All you'd need to do is remove the red cap, feed the spring in, and reinstall the cap.
 

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Jim always talks about the initial hit with his MP was more violent than the Whipple he is running now.
It is true. But to be fair, the MP was running a LOT more pulley. The twinscrew builds boost some with RPM. The MP hit at full boost right now! The Whipple makes loads more power up top and a lot more under the curve, though. I

I do miss that "Hit" and the sound of the MP screaming!

Jim
 

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I choose the eaton for reliability and the instant punch, for the big truck.
 
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