Finally Made it to the dyno...what's the breaking point??

[0mineralgrey3]

Scheduled some time with the car today. Hit the Rollers early this morn. It was freezing cold outside.

A list of mods currently are JMS upper pulley, 10% lower, Reichard Tensioner, jlt intake, twin 65mm TB, NX plate kit (50 shot) Custom Bullet Racing Cams, ARH 1 7/8 headers with off road X, Corsa Mufflers, 3.73 gears. I had my 275/60/15 drag radials on.

I never made a pull with the Nitrous as I was nervous about breaking. The first pass he pulled it to 7000 rpms. He said he can feel the stock clutch slipping up on top. Boost peaked at 19.8 on the hit and fell off to 11.3 at 7k rpms. It saw 755/849 with belt and clutch slip.

We let the car sit about an hour for the clutch to cool off before the last pass. This time he ran the car to 6500 rpms...still had some clutch and belt slip. This time it saw 20.2 lbs on the hit and fell to 11.6 at 6500. Power showed 770/864.

Who knows what the outcome would have been without belt slip and clutch not holding. I didn't want to spray the 50 for fear of a rod chickening out on the pull. I'll drive it and play with it tomorrow...and i'll see if my buddy will send me the video.

Crappy Vid from my friends Iphone.

 

[scottGT500]

Goodness! Some nasty power going on! How do you like your exhaust setup? AR, o/r x, Corsa? Thanks!

Scott

 

[0mineralgrey3]

Love it.

Here's a vid of it

2014 gt500 custom cammed walk around - YouTube

 

[Ninjak]

A RXT will solve that clutch issue easily.
Nice setup for sure

 

[19COBRA93]

Killer numbers. Pretty brave pulling that high at that level. I'd be surprised if the clutch was really slipping. That's kind of a strange scenario for it to slip. It would slip at peak torque long before it would slip at the top of the pull only. Could you smell it? If it slipped on the dyno, it will definitely slip on the street.

My numbers below were made on the stock motor too. Not a '13 I know, but very similar in failure limit.

 

[GT500-lolz@MPG]

Holy effing torque 863!! Uhm 20.2 PSI what octane are you running?!?! Seems like you have more room up top..

 

[Superhawk2002]

Any future plans for upgrading the rods? Thinking of swapping the cams on my car in a few months.

 

[0mineralgrey3]

I was on pump gas. It spiked 20 on the hit and fell to almost half. I didn't want that much boost and I will be putting the stock upper back on.

RXT sprung hub clutch is on the way. Same one I had on my 2013 and loved it.

I could hear and smell the clutch slipping. The rpms were kind of hanging up.

No plans for Rods until these quit on the job. I Don't beat on my car much so Hopefully they hold up.

 

[2011 gtcs]

Impressive numbers man, and the car sounds so sick with the cams

 

[rancid]

New clutch and an e85 tune you should be in the 800's!

 

[TORQJNKY]

No plans for Rods until these quit on the job. I Don't beat on my car much so Hopefully they hold up.

You wait until that point and you will be buying a new motor, not just rods! And I just have to say this...HOLY TORQUE MONSTER! It almost looks like you sprayed it!

OK, what fuel system mods do you have and do you have a graph that shows A/F? Something is not right. No way should power drop off like that at 5500rpm. The belt or clutch may have been slipping but like 19COBRA93 said, it's strange that the clutch wasn't slipping at peak torque.

So here's my story, same exact scenario as you except on E85 at only 16.8psi. On the dyno at WOT around 5500-6000 rpms, power and boost was dropping off significantly, sounded just like belt slip. Changed my upper pulley to a Reichard Racing pulley while on the dyno and it did the same thing. Turns out, the car was just protecting itself. The PCM has logic to "save" the motor by closing the throttle under a lean condition. It was running out of fuel up top and closing the throttle body and dropping boost because it was sensing a lean condition. Sure enough, when you looked at the log, A/F started going lean at the same time this happened. I was on E85 at the time, so I had a nice comfort factor. But 19-20psi on pump gas is crazy and asking for trouble IMO!

Whatever happened to cause you to drop boost and power, probably saved your motor.

 

[Bllit11]

Wow

 

[Bllit11]

By the way how much is a new engine?

 

[TT91Coupe]

25k

 

[Devious_Snake]

Good call pulling the upper off and going back to stock. That might help with some of the belt slip and also on 93 you dont wanna push that much boost and in cold weather. Also what fuel upgrades like Torq mentioned? That power drop off up top is saying something

 

[May93]

Damn that sounded good!

 

[BlownMystic1]

Wow, that sounds nice. If you don't mind me asking. Whats the cost on the cams?

 

[Bllit11]

25k ouch

 

[0mineralgrey3]

A/F was 11.5 up top. I have a JMS boost a pump. The Belt had rubber dust all over it...and it was definitely slipping.

In my 13 my clutch was toast with less modifications and we all know the failures they've had under less power.

The cams ran me about 1200. Installed them myself in less than a day. I have a thread in this section about them.

 

[dubbsfaris]

Yikes. Im just not that brave.