Gee Gary, don't hold back. LOL

But it is true that it will take a whole lot more than an exhaust to get 10+% increase. It's sorta like those exercise machines they sell on tv. They make it sound like you will lose the weight if you just use the machines, but really you also have to diet and be consistent etc and the results highly variable.
Note they usually say up to XX hp. How do they reach it? With other mods.
Do a search on Adrian Streathers Sportec mod for the 964. He just got 35hp from MAF, Chip mod AND cat mod.

 

Actually, I have an independent dyno chart showing that my GHL exhaust added around 15rwhp and 20lbft of torque on my car when it was standard. I did nothing else to the car, no rechip, no cams - just a system reset and we got rid of the O2 sensor. The GHL is not on there now as my car is so far from stock that we couldn't get the Motec mapping right with the GHL installed.

9M have already proved that another 35+HP is possible with just a live remap and a catbypass......even without changing just one cam as you suggest above.

Hopefully you will have some specific knowledge of these things before repeating what you have heard from your buddies who by the sounds of it have not tried these things out either?

I am using this tone with you as I find the one you used above totally unnecessary.

 

Christer, thanks for the info. Was this dyno done before and after? or did you just do a dyno after the install? My car when new in 94 dynoed at 254.4 FWHP and this was CA spec. I got lucky with a strong engine and at 56k it now produces 245 FWHP when dynoed last year. Of course temperature and other variables play into it. Also why did you remove the O2 sensor? Wouldn't that just run the engine too rich?
What I'm saying is without a baseline dyno done in similar conditions, that 15hp may be 10hp or less. Just my 2 cents.

 

Hi Eggplant

My own exhaust was falling apart a few years back, my CAT and final muffler etc were pretty badly rusted and I wanted a stainless system that would last awhile. I read the 28hp and tq claims and thought nothing of it, in fact I told JZ Machtech here in the UK of the claims and they rubbished it as I did. The car was dynoed as was, the GHL system was fitted and the car was dynoed again a couple of hours lateron the same dyno. JZM were as amazed as I was. In fact, I believe they looked into importing the system to the UK but the cost was just excessive I understand.

Here are the dyno charts.....(I didn't even remember that I had these so you will see that my memory was slightly hazy with regards to the figures - hopefully they will be viewable as they are faint and now reduced in size).

 

p.s. - you will notice that my car was a little down on power (after 85K miles), from memory I seem to remember that it was producing 207rwhp and about 222rwhp after the GHL....

 

Thanks Christer. I'm impressed with the exhaust power improvement. Was yours the complete header with cat kit and heat exchangers or the bypass kit? I'm actually thinking of replacing my exhaust and a MAF kit and chip. Since my tires are already up to 17" I figure the extra stopping power deserves a little pushing power.

 

My car runs a MAF and modified exhaust and in my experience based on dyno results, butt dyno, measuring terminal speed over a set distance ( between 2 traffic lights about 1 mile apart) and comparative performance on track, I'd add the following;
The MAf with enlarged throttle body and live remap is worth about 40hp over the stock ( 250hp) car. IMO if you're not intending to open the engine and you can find someone with the experience to get it right it's a no brainer and possibly the most cost effective bolt on hp you can get.
Bypassing the cat is worth about 5hp, bypassing the muffler/s probably slightly less. I lost about 20kg out of my exhaust and I'll bet the power/weight ratio improved more through the weight loss than the hp gain.

 

The GHL system that I have is the complete headers with heat and all the rest of the bits.....this system bypasses the CAT in any case (as I didn't need it) but you can buy a GHL CAT as far as I remember if you need it for smog or similar.

 

If I had a convertible, I would just enjoy the way it is....That's what it design for....

 

Point taken, allthough some improovements can be made, as one sees from this thread.

Miguel

 

Well, Miguel likes it a bit more "raw" as I do. I just won't sacrifice emissions and too much more noise for the raw feeling. I still like driving my 964 cab more than my 997 Cs in every environment except a track.

 

Hey Miguel, you pressed one of the buttons that gets everyone's opinions going there ! Just don't mention whether or not one should remove the engine tray for better cooling! or the thread will turn into a real 'sacanagem' !

 

well, i have no dyno proof, but my old 964 with 120k miles on it felt like a totally new car after the following"
1- cone air filter
2- cat & primary bypass (local muffler shop)
3- cup chip ( bought it off ebay for 45$, seller claims its a copy of a real cup car chip), made the biggest difference, both in smoothness and pull
everything costed 220$ and all i can say, it works

last week, i drove a 91 with an authotority mass air flow and b&b exhaust, felt like a rocket, 2 bad the car had some salvage history.

people that dont believe you can gain few horses from the following need to get a life, try it first then speak out!!

 

I dislike the generic claims some vendors put out there about quick bolt-on power. In Christer's case he changed out his O2 sensor (was it bad before the change?), a CAT bypass, and exhaust and got more power on a dyno run. Not a controlled test, one or two pulls on the dyno, one car, and approximately HALF of what the Mfg. claims (does GHL mention you need to bypass the CAT to get the 28HP?.. don't know, just curious). I can believe HP gains (varied) from multiple mods like Adrians but just by changing the exhaust system itself without intake or fuel modifications? I installed a Fabspeed dual-out, which I consider a better system than the GHL, and felt absolutely no difference in the car. I did not remove the CAT (Emissions tests here) not install custom headers (Need heat here). It did sound great though.

Christer -
My "tone" was a stating of MY opinion of what I consider exorbitant claims by the "bolt-on-betty" instant power mods, nothing more. If you have some sort of problem wih me, which is fairly clear from you imflammatory remark, I suggest you take it up with me (or Marc Shaw) privately rather than post about issues you clearly are clueless about.

 

It's not just a muffler, it is headers, heat exchangers etc.