Ever since i put a ported throttle body on my truck my boost won't go up to 11 like it always has. It will sometimes go to 9ish for a second but then settles down to 6 or 7 at WOT. I called whipple and steve said, "you definately have melted your catalytic converters running that much boost and a piece is lodged in the muffler and that's causing your boost to be decreased. It can't be anything else, you're gonna blow up your engine."

So, for some reason, i listened to the dick and bought new cats and a new muffler. $850 later after installation, it sounds great, but, the cats were in perfect shape as was the muffler and my boost still won't go above 7ish. My belt isn't slipping as far as i can tell, no powder around the pulley. I'm not using the whipple electronics. the only thing i changed was the throttle body. I'm not getting any vacuum leaks. i sprayed carb cleaner all around the maf, intake tube and tb. iac is around 40 at idle. no misfires. i'm lost. the truck still feels strong, but, where's the boost?

 

put the old t.b. back on. i could see a slight decrease in boost but not 4 lbs..

 

Less resistance in the intake tract equals more efficient and less boost. Remember, boost is just a measure of resistance. I bet you didn't loose any power.

The only thing fishy is I don't know if it will decrease it by that much, that is definately significant.

 

but isnt the throttle body before the whipple...? there for that would not cause a less of a restriction after the blower. that would be more like taking your air filter off, and that would actually increase boost pressure...
Louie

 

Damn, good catch. I thought he had a centrifugal on there. Less restriction before the blower would probably increase boost. What do you guys think.

 

Does the belt look to be in good condition? How about the Boost gauge line itself? Is there a kink in the line or leak ? Check those 2 and report back !

 

I'd be checking for belt dust.

If the TB was after the blower I would agree that seeing less PSI is a good thing in all ways. Less heat and same CFM.

If the TB is before the blower I wonder if having the intake tract opened up is causing the blower to work harder and making the belt slip? Not sure how that works on those TwinScrews. I'm used to centrifugals and turbos.

 

I had the same problem once with my car Id hit full boost sometimes somtimes I would feel it boost but the gadge would real like 2# couldnt figure it out checked the line for the boost gadge had a good kink in it.

 

You didn't mention a power loss or gain..

If you notice it feels like it's losing power you might be frying the trans as well. If it starts to slip wouldn't that show up as a loss in boost as well or is that only with turbos because the load is decreasing?

 

if you have time this weekend get it on the dyno and see if you lost a lot of power then you can see what's going on swap out t.b's while on the dyno and see if your problem goes away.

 

For starters don't ever listen to those folks again. Plugged exhaust on a supercharger car will actually increase boost. A definitive increase in boost indicates a restriction in the exhaust, not a decrease in boost.

If I had to guess I would say either your belt is slipping, or your means of measuring boost is not working correctly (hole in the sensing line?)

A larger inelt on a whipple, if it flows more air, will actually work the supercharger harder. The extra work that the supercharger has to put into compressing the now extra air coming in puts extra load on the belt. I am leaning towards belt slippage. Can you try increasing the tension a little?

 

I did recently have a new torque converter put in, a Yank SC3000. I do notice what feels like some slipping when the tcc locks. but only in 4th gear, at low throttle position. YES, the tb is before the whipple. I'll go check the boost line today. At first I did feel like I lost a bunch of power, but, i think after setting the idle/IFR it feels like the power is back. Took awhile for the truck to learn the new TB. I'll go buy a new belt today and replace the line on the gauge. Thanks for the input, i hope its a simple fix. STEVE AT WHIPPLE IS A TOTAL DOUCHBAG!!!!!

 

Ok, new belt. No difference. It's so strange, i now can't get the boost over 5lbs and I can't keep it there. it immediately starts slowly dropping. i'm thinking maybe it's a trans problem. feels like its shifting too soon or something. i'm waiting for my eio cable from hptuners so i can't even go log any data to try to figure it out. Oh, and the boost gauge and line seem fine. i see no kinks etc.

 

well since its before the blower are you 100% sure the throttle blade is opening all the way? I dont know if your year is drive by wire or not, if it is maybe the TB is just screwed up. cuting off the air to the inlet of any blower will reduce the output quite a bit.

 

Valves are probly floating.

 

um, i'm an IDIOT. i had cut the boost line at some point to hook up a solenoid for the whipple boost a pump which i am no longer using. when i spliced it back together i used electrical tape to hold it in place. it LOOKED fine, but, when i tugged on one end of it, it was totally loose inside the tape. I can't believe it was such a stupid little problem. anyway, it's fixed and now my alcohol injection actually works because it is seeing the right amount of boost. sorry for wasting everyones brain cells.

slowhawk, sorry if i was a dick in the past. i need to get back down there sometime to have you tweak this thing. I bought an innovative LC-1 wideband and upgraded to a eio cable on hptuners. should have it all hooked up within a week so i can get the a/f in check. currently, i'm seeing kr almost all the time.

 

glad to hear that you got it worked out.