Hey guys,
Just got my project done of putting in a VNT17 and getting a Malone stage 4 tune. The turbo was spiking about 25 and leveling off at 21-22 before the tune. Now with the tune it can spike upwards of 35! Usually it's about 30. This tune an setup is suppose to be doing about 21-24 with a spike of 25 tops. I do have a 3 bar map sensor installed along with the tune. No exhaust work has been done. EGTs don't run over 1,000°. I replaced the N75, no change. The checkvalve was replace with most of the vacuum system last year (rotted out actuator on the KP30). Malone insists it's a mechanical issue. I don't think it is because it boosted fine before stage 4. I had stage 1.5 before stage 4. I did calibrate the actuator on the turbo to spec, then lengthened a bit more, still spikes 30-35.
Vacuum read ~20-25Hg at the vacuum ball. At the check valve off the brake booster hose it bounces a lot. I'd say 20-40Hg? I thought this was odd. It does need a new brake booster hose. The crack has been bandaided for now but I don't think that's the cause.
My question is, can a restrictive exhaust cause over boost? Is there any other things I would check? I'm at a lost other than dumbing down the tune. I will be making some logs to submit to Malone and see if we can pinpoint where the problem is!
If anyone has any ideas, I'm open ears thanks guys
Just got my project done of putting in a VNT17 and getting a Malone stage 4 tune. The turbo was spiking about 25 and leveling off at 21-22 before the tune. Now with the tune it can spike upwards of 35! Usually it's about 30. This tune an setup is suppose to be doing about 21-24 with a spike of 25 tops. I do have a 3 bar map sensor installed along with the tune. No exhaust work has been done. EGTs don't run over 1,000°. I replaced the N75, no change. The checkvalve was replace with most of the vacuum system last year (rotted out actuator on the KP30). Malone insists it's a mechanical issue. I don't think it is because it boosted fine before stage 4. I had stage 1.5 before stage 4. I did calibrate the actuator on the turbo to spec, then lengthened a bit more, still spikes 30-35.
Vacuum read ~20-25Hg at the vacuum ball. At the check valve off the brake booster hose it bounces a lot. I'd say 20-40Hg? I thought this was odd. It does need a new brake booster hose. The crack has been bandaided for now but I don't think that's the cause.
My question is, can a restrictive exhaust cause over boost? Is there any other things I would check? I'm at a lost other than dumbing down the tune. I will be making some logs to submit to Malone and see if we can pinpoint where the problem is!
If anyone has any ideas, I'm open ears thanks guys
Last edited: