Clutch slip causeing low numbers?

[02trubluegt]

Had my 2013 dynoed on 2 different dynos, 1 for chairty and 1 for a bet with a fellow club guy.

Mods are Boss Manifold, JLT Intake, Off Road Xpipe, Corsa Axle backs, LU47s and E85 with a Lund flex tune.

Car made 406 whp and between 350 and 355 tq on both Dynos. Normally im not a stickler for mods or numbers, but this didnt seem right... especiall when a guy with same mods on a bama tune and 93 made more power.

2nd Dyno was gearheads Performance in Arlington, TX. Told me he felt alot of negative clutch pressure. Felt as though the clutch might be slipping up top. You can kinda see on the graph where the curve gets very rough up top.

Anyone here have any thoughts?

 

[Zemedici]

He smoothed the graph to make it 'prettier', that will affect numbers

Dyno is solely a tuning tool, not meant for an 'end all' for power. However 400whp with a Boss IM is low. A slipping clutch will definitely attribute to that.

 

[02trubluegt]

He smoothed the graph to make it 'prettier', that will affect numbers

Dyno is solely a tuning tool, not meant for an 'end all' for power. However 400whp with a Boss IM is low. A slipping clutch will definitely attribute to that.

Oh I understand its not the end all. When 2 dynos give you that number something seems off. Especially when same mods on 93 is making more than e85

 

[Zemedici]

Oh I understand its not the end all. When 2 dynos give you that number something seems off. Especially when same mods on 93 is making more than e85

a NA car wont make much more power on E85 vs 93 Octane , but yes it appears there may be a mechanical issue. Have you noticed the clutch slipping?

 

[02trubluegt]

a NA car wont make much more power on E85 vs 93 Octane , but yes it appears there may be a mechanical issue. Have you noticed the clutch slipping?

I havent noticed any slippage. Car has 60k on it, was also thinking since brake and clutch fluid is 1 line... maybe old bad brake fluid, not having enogh pressure anymore. Maybe clutch cylinder going bad? appreciate your input

 

[nxhappy]

is it the stock clutch? how many miles on it ?

in a parking lot stop the car, put it in 3rd, release the clutch. It should stall. If it doesn't stall and RPMs go up, the clutch is slipping.

That being said, every car will dyno different numbers. Maybe you need a different tuner.

 

[nxhappy]

I havent noticed any slippage. Car has 60k on it, was also thinking since brake and clutch fluid is 1 line... maybe old bad brake fluid, not having enogh pressure anymore. Maybe clutch cylinder going bad? appreciate your input

with 60k the clutch might be going out ...do the stall test I mentioned

 

[02trubluegt]

is it the stock clutch? how many miles on it ?

in a parking lot stop the car, put it in 3rd, release the clutch. It should stall. If it doesn't stall and RPMs go up, the clutch is slipping.

That being said, every car will dyno different numbers. Maybe you need a different tuner.

appreciate this trick... I didnt even think of that. Car stalled right away.

 

[02trubluegt]

I also did email Lund, and see what they advise. and Yea a new tuner may be in order her shortly. Gonna maybe get the fluid changed out to something fresh... i bought the car with 35k and i havent changed fluids so as far as i know its 60k on orig fluid... maybe bad?

 

[nxhappy]

I wouldn't worry about it man. If AFR looks good and fuel looks good. Every car is gonna put out different numbers. It's probably fine, especially if the motor runs good.

 

[nxhappy]

and yes change that fluid for sure.

 

[02trubluegt]

well... all i saw and monitor sinces the 11-14s cant read below 10... is lambda. it looked good, but gearhead the guy who dynoed it said it looked a lil lean up top, well leaner than he would tune for... whatever. As long as nothing blows up.

 

[02trubluegt]

I was thinking if its weak fluid its just not holding pressure up top on the clutch as it heats up and the clutch is letting go... i dont know. Ill slowly start things. Ill see what lund sais as well.

 

[nxhappy]

that is true. oil fluid could cause issues.

 

[SVOGT302]

Fluid shouldn't matter if clutch is engaged.

Sent from my SM-N910P using the svtperformance.com mobile app

 

[Jumpmaster2015]

Oh I understand its not the end all. When 2 dynos give you that number something seems off. Especially when same mods on 93 is making more than e85

You can expect a 7-12 HP difference with pure E85 on a NA setup, and its the time of year where that winter blend crap is popular.

 

[nxhappy]

You can expect a 7-12 HP difference with pure E85 on a NA setup, and its the time of year where that winter blend crap is popular.

way more than that. depends on the advanced timing.

 

[Jumpmaster2015]

way more than that. depends on the advanced timing.

This is what a reputable tuner says that I put a lot of faith into. If you want big E85 gains then you need to go boosted.

 

[Shaun@AED]

Clutch slippage on the dyno does not look like that, FYI.
RPM's would shoot UP and the tires would not increase in MPH. Your clutch is holding just fine on the dyno graph posted.

 

[WhiTriCobra]

First...+1. You would see rpms sharply rise but not MPH. 2nd, why did he only pull to 7K rpms and not around 7800rpms? You can see at 7K rpms it starts to climb but he stopped the pull. Following the graph, could have been around 420-430 (though STD, take off around 10rwhp for SAE).
3rd, datalog next time on the dyno. And 4th, if you use E85, I would buy a tester to see what you are truly getting.