Hey guys/gals ive been saving for a while now to place an order through Hahn and get everything as far as bolt ons (Down pipe, cat back, and charge pipes). Only thing i wont have is the intercooler. My issue is that with the research i have done here on our clutches, which seem to be a decent weak point, i dont know if my clutch would slip after i tune it. I know it would be fine if i just got the bolt ons and didnt tune it but what would be the fun in that. The problem im running into is that the threads im finding are old and usually dont have a direct answer. Ive read that 350 hp is when i would need to change the clutch out because it would slip but what about the torque? I would assume that torque would play more of a factor than the HP. I also looked though the 2012 dyno thread and the fact there could be quite a significant difference between two car with the same mods just made finding an answer a bit harder. So with GMS1, Intake, Cat back, Downpipe, Charge pipes, and a tune would it be a definite that the clutch wouldn't hold? Im crossing my fingers that it will be fine since that doubles what i would have to pay for my car to be full bolt ons.

Thanks in advance.

 

Depends on who does your tuning and how they setup power delivery. It also depends on your driving habits, whether you NLS and whether or not you like to do digs/run at the 1/4 mi with the car.

FWIW, I'm on my stock 60K mile clutch and I'm pushing well over 400wtq - Zero slip. I've had the car since 30K miles and it's been tuned by me since I took ownership.

Good luck man!

 

Currently i drive the car a couple time a week just to joy ride. I avoid the NLS since i read that you shouldnt really use it. When i joy ride i usually do a few pulls from 40 to 80. I also dont use launch control. If i run into someone that wants to race i tend to ease into the power instead of just flooring it. As far as the tune i figured i would get a mail order tune from Hahn. I drive to NC from KS a couple times a year and i would like to keep my 30+ MPG. So i figured i would swap in the factory one on those trips.

 

On 91 with hpt just about any stock clutch on any mileage cobalt SHOULD hold. 60k to 130k miles it should hold. On e47 it shouldn't with that extra torque but it varies the car and how the previous owner drove.


Replacement clutch should be the GMPP clutch from the LSJ, works just fine on the LNF and holds all Stock turbo Full e85 torque.

 

How many miles does it have on it? You should be fine as long as you ramp the boost in and drive it responsibly. Having the clutch as the weak point is better than having the trans as the weak point. FYI- I've heard Hahn is really busy so you may be waiting a bit. If you have hot you can get remote tuned by another good tuner.

 

As other have said, it depends a lot on the tune and how the power delivery is.

I am self tuned with HPT. I only have a IC and drop in KN filter. I had no problem getting the clutch to slip in 4th and 5th at 4K rpm and under. I could even get it to slip a little in third when I was ramping in torque rapidly and aggressively. I was GMS1 previous to that and had absolutely no slip, but that tune keeps boost down a little under 4500-5000 where it will finally allow "full" boost that would reach 20-21 for me. I am guessing they did this to keep the clutch happy.

I tuned to 23-24 psi on 93 octane.

To eliminate clutch slip I ramped boost in gently from 2500-4000 overall. But even then 4th and 5th gear might slip some. So then I set 4th and 5th gear to limit them separately even more under 3000 rpm (16psi max) and keep them down to 21-22 psi from 3000-4000 rpm (where 2nd and 3rd will be 23-24 psi in that range).

That kept the clutch happy and it does not slip at all.

All this boost ramping and torque limiting I have done (and most other tunes for a stock clutch will do the same) is leaving power on the table under 4000 rpm (or wherever the tuner ramps to, sometimes as high as 4500 rpm). The turbo can spool a lot harder a lot lower than that if you had a clutch to take it. So peak torque might be down a little when tuning this way. You can see guys that are stock-ish (or a few bolt ons on stock turbos that make 310whp and 360wtq (better clutch), and guys making 310whp and 330 wtq (stock clutch). But both setups would make exactly the same power/torque from 4500 rpm and up. Just a ball park example of what boost ramp might do when used with a stock clutch.

If the tune is good, it will ramp in boost/torque and you will not have to do it with your right foot like you state you are doing now. But since every clutch is a little different, especially after a lot of miles on it, getting that tune to be aggressive as it can be, but limit clutch slip can be a trials process.

 

^this. i made 410 hp on the dyno with a stock clutch. i don't plan on changing it anytime soon

 

Thanks for the info on the clutch. I went through a few threads that just ended up turning into an argument about who had the best clutch lol.

I just broke 100k on the car. I agree with you on the clutch issue. Im just used to auto cars and most of them could handle up to 500-600 with no issues. So dealing with this is new to me. Im a noob to tuning, what is Hot? Im assuming you meant HPT?

Very very detailed. Thank you for the info. I mighty just have to get a custom tune then instead of a mail order. I would just have to remove the tune 4 times a year which could get annoying.

 

I wouldn't look at it as leaving power on the table though. The stocker and even the big wheel ported stockers can only flow so much. A great power band can be realized with either by doing your due diligence to limit (using whatever strategy you prefer) the massive torque spike. So that means, using your example, the car with the "limited" power delivery may not make the most peak torque but is going to move the HP peak to the right. This would allow it to carry out further, which = a faster overall car as it's less likely to light the tires up and HP isn't nose diving after 6K RPM.

Side benefit is that it makes for a happier clutch too

Why would you need to remove it? It doesn't alter the emissions capability of your car?

 

I make a 2k mile trip 2-3 times a year so im a bit worried that ill lose my 30+ mpg that i get now. Last vehicle i had and got tuned took a big hit on fuel economy. And then i also need yearly inspections.

 

Fuel mileage will only go up, so long as you can keep your foot out of it. The tune wouldn't affect the inspection either.

 

Ill just need to get it tuned after the bolt ons then. Im still always going have a voice in the back of my head warning me about the last tune. Because of it if i lose any MPG on this one the wife will give me a **** storm. Thats what im trying to avoid lol.

 

You should be fine. I'm not the best when it comes to keeping my foot out of boost, but I still average 31mpg with the car most tanks.

 

I found that after I self-tuned that my DIC reported higher average mileage under what I consider to be basically the same driving commute and driving habits.

There really is no reason a tune will affect negatively gas mileage for basic highway or commuting. It tends to stay the same for most tunes I bet, as the tune primarily affects the high boost areas. If they do touch low boost and vacuum areas of the tune, it usually just improves gas mileage a little.

 

Yes, not really power left on the table, as peak power isn't until above that anyway. But in a road course application I would prefer to maximize power (torque really) starting at 3500 rpm, and I am still ramping boost in at that point, meaning I could have more torque available coming out of a turn if the clutch could take it. My last car (Toyota turbo setup) made peak torque starting at 4000 rpm and made good power all the way out to 7500rpm. Nice broad power band of 3500 rpm (really still made good torque as early as 3500 rpm, so a 4000 rpm power band). The LNF with boost ramp is a little narrower in it's power band, but not terrible.

In a drag race application it certainly does not help to have more torque down at 3500 rpm, so boost ramp has zero impact there.

 

After I tuned my car my MPG went up. If I keep it at a steady 70 MPH and stay out of the pedal I average around 32 - 34 (it is fairly hilly here which is why there can be a big variance). If I keep at a steady 65 MPH I can pull about 35 - 36 MPH. If I drive at a steady 60 MPH I can pull about 38 - 40 MPH. I pretty much drive about 70 MPH to keep up with traffic around here. Anything under 65 and every car on the highway is passing you like you are standing still... LOL