Car at tuner. Car falls on its face at 6k Part 2.
11-23-2016, 12:22 PM
#1
Car at tuner. Car falls on its face at 6k Part 2. So I just sent my car back to the tuner to have it tuned for nitrous and to correct an idling problem. And the car is still doing the same thing I mentioned in this thread-
https://ls1tech.com/forums/generatio...s-problem.html
I eliminated two of the variables since the last thread. The car's fuel pump was upgraded to a Racetronix w/hotwire kit and the flimsy rubber couplet was replaced with a hard silicone based one without ridges from intakehoses.com. Also, before I picked my car up from the last time, I had the shop switch back in the old plugs (NGK TR55s I believe) and the car did the same thing soo I dont think its the plugs.
But the car is doing the same thing- it falls on its face just past 6k RPM. I am at a loss here. Does anyone have any earthy idea what is going on with this car? The shop suspects mechanical but nothing mechanical within the engine changed from when they first dynoed my car after the head and cam swap and the car ran fine. It was only after I took my car back to be returned for the Fast 92 mm intake, 42 lb injectors, and having colder plugs installed that the car started plummeting at 6k RPM.
The car does have an Ebay TB that was also the source of the idling problem as the TPS sensor was coming loose. Could this somehow also be what is causing the nose dive past 6k RPM as well?
https://ls1tech.com/forums/generatio...s-problem.html
I eliminated two of the variables since the last thread. The car's fuel pump was upgraded to a Racetronix w/hotwire kit and the flimsy rubber couplet was replaced with a hard silicone based one without ridges from intakehoses.com. Also, before I picked my car up from the last time, I had the shop switch back in the old plugs (NGK TR55s I believe) and the car did the same thing soo I dont think its the plugs.
But the car is doing the same thing- it falls on its face just past 6k RPM. I am at a loss here. Does anyone have any earthy idea what is going on with this car? The shop suspects mechanical but nothing mechanical within the engine changed from when they first dynoed my car after the head and cam swap and the car ran fine. It was only after I took my car back to be returned for the Fast 92 mm intake, 42 lb injectors, and having colder plugs installed that the car started plummeting at 6k RPM.
The car does have an Ebay TB that was also the source of the idling problem as the TPS sensor was coming loose. Could this somehow also be what is causing the nose dive past 6k RPM as well?
11-23-2016, 12:32 PM
#2
I had a very similar problem a while back. It happened after I put bigger 1 7/8" headers on the car. I gained low and mid range power/torque, but the car fell on it's face at 5,800 RPM's and continued to plummet the higher we spun it. I recently changed out the cam, and the problem was resolved. The issue with the old cam was that it closed the intake valve at 38.5 degrees after bottom dead center, which is really early for a performance camshaft in a LS1. My heads have extremely strong exhaust ports/flow, just like your do. That could be your issue. The new cam I'm running was spec'd out by Cam Motion and the valve events are suited to the flow characteristics of the heads. I bring this up because the heads we run are similar in that they have extremely great exhaust flow, and really need a cam spec'd according to that.
11-23-2016, 02:59 PM
#3
I haven't changed the exhaust setup though and the heads/cam setup did perfectly fine with an LS6 intake at the same shop dyno. Its after the Fast 92 intake switch that this problem started- which makes me wonder if the cheap throttlebody is somehow a factor. But I definitely do not want to throw 400$ at an overpriced air blade unless I'm certain that is the issue.
