Installed a set of Jammer 5's on a buddies truck. Ever since then, his 99 5spd has a shudder at WOT. At first it would only do it with juice on level 4,5 or 6. Now it will do it in level one but only in 4th and 5th gear in level one. Funny thing is that the shudder happens at 26psi and the wastegate has been disabled entirely with a pipe plug on the compressor housing.

I have three theories:

Note: problem has gotten worse with time. Now the problem happens with Juice on level 1 whereas before it only happened on upper levels.

1. Wastegate is blowing open at 26psi boost, high elevation 26 psi could mean huge drive pressure.

2. Injection pump itself is shuddering like the TST Comp does or the injection pump is getting weak, however, I thought the shudder from the TST only happens when you let off?

3. Clutch is slipping. Maybe 26 psi is where the motor starts to make real power and the shudder is from it slipping. The clutch does not slip noticably unless you try to do a burnout in 2nd gear. It is a luk pro gold with higher plate load rated at 300HP.

So, what do you all think the problem is? He has adequate fuel pressure, and never had a problem before when he was running RV 275's. Since the Jammers it has the problem. Is it just the increased power from the bigger sticks making the clutch slip on the top end?

 

does it idle funny i put stage 5s on my truck with a drag comp right after i got it and it started idleing funny and it was shuddering in the higher rpm range it was really noticable when i was in a higher gear i drove it like that for a little while then i blew the front out of the head gasket and when i pulled it apart it was blown in like 9 places so me and J7 Diesel figured it was the motor just missing because i wasnt making the compression i needed to. also with my wastegate unplugged i was hittin 54 55 psi

 

It hits a max of 36psi with juice on level 6 which is equal to drag comp. His truck idles pretty smooth, no problems except this new shudder. My vote is clutch but that is an expensive gamble if it is fine and the IP is on it's way out. And if it is just normal than any fix is a waste of resources.

 

Anyone have any ideas or theories, it would be nice to get some more ideas before we tear into his truck.

 

I've heard that excessive timing could cause the issue you describe.

 

Sounds like what mine used to do. My problem was that the wastegate was fluttering due to back pressure. I tightened up/shortened the w/g rod a few times and it cured it.

 

OK, so we've got one vote for excessive timing... ie.. IP trouble, so would adding jammer nozzles over RV 275's cause that much increase in timing to cause this problem?

And one vote for wastegate trouble/ fluttering

 

try the tightening up the wastegate.... its free to try and will only take a few minutes.

 

By tightening up, you guys mean shorten the shaft. What if we just wired it so the shaft cannot move, will that keep the gate shut? If the spring is weak and letting it open early, even though the line is totally plugged and disconnected, should we wire it so as to put positive pressure effectively pulling the shaft toward the diaphram and away from the turbine housing? Will this help it out if the spring is tired?

 

Get one of those adjustable elbows that way you dial it in and still have some sort of wastegate.