[MCL968]

There's an RS Barn exhaust for sale in the 'parts for sale' section if anyone near socal needs one.

Bombfactory,

 

Just sent you a note. If it does not come through, please contact me at demaan390@yahoo.com  I will be in OC next week.

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[wildcat]

The fastest and cheapest way to get a little performance improvement, lose some weight and enjoy that throater sound of which the 968 is capable is to remove that triangular resonator at the center of the exhaust. I love it...

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[flash]

it's been tried.  you actually lose some low end torque when you do that.  you do get 2-3 upper end hp and the nearly 20lb weight loss though.

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[wildcat]

I'm sure it has, I'm just suggesting that it is a very economical way to obtain some very desirable results. Losing low end torque on this hi-torque motor with a Tip I would suggest is unnoticeable and it does seem to unleash the motor, but that could be psychological and strictly associated with the resulting growl.   B)

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[optigolf]

If the cost of the modification is not too big issue to do the changes from the engine to the tip to get more hp and nice low sound, has anybody firm test results what would be the solution. I have already air box modifications and looking to put new zip in. I like to get both of those, some more hp and nice low sound to my convertible.

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[flash]

lol - supercharger

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[optigolf]

Flash, as I wrote I am looking currently best solution for the exhaust solution, so any proven and good solution to that ?

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[flash]

not for normally aspirated

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[optigolf]

Flash, should I make assumption then that all what I can read on this forum and what people are writing here does not make any sense and are not real, no gain on hp or getting better exhaust sound, for Porsche 968 ! It works on other cars.

I suppose supercharger and improvements to exhaust system are two a bit different issues. Also I suppose that with supercharger it is needed better exhaust system also, to get it work well and to get the right outcome ?

Anybody else have any comment to my original questions of improving hp and sound by improving the exhaust system to 986?

Thanks, Mark

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[flash]

this car is very odd.  they tuned the exhaust carefully, to work with the dual resonant intake manifold, and cam overlap.  even the catalytic converter is tuned into the system.  what works on other cars, generally creates huge torque losses on this one.  countless efforts have been expended, and i and another have spent over $10k each trying to find gains, to no avail.

 

there is no performance to be gained by any cat-back.  some systems have some minimal upper end gains, but also are accompanied by lower end losses.  most driving is at the low and middle rpm range.  this is not where one would want to lose torque.

 

sound is a different story, and very subjective.  what one person likes, another may hate.

 

with a supercharger, there are gains to be made, due to the increased amount of flow.  the OEM system is too small to really take advantage of the supercharger, and while it can be run just fine, it will perform better with a freer flowing system.

 

there are quite a few threads about this already though.

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[wildcat]

Flash, as I wrote I am looking currently best solution for the exhaust solution, so any proven and good solution to that ?

As cost is not a restriction, then consider this because it is very inexpensive.  Removing the triangular resonator and putting in a tube to fill the space, a spliter to funnel it back into the muffler which has two inputs is "cheap".  If you don't like it its an easy matter to put the resonator back in.  Yes a little welding is required but all else being equal its a very inexpensive mod.  I think it does improve the performance, I have not noticed any deterioration.  Another issue related is the sound. Having spoken with several muffler guys, they've all said the same thing.  The stock muffler is a good one, the tinny sound comes from the design of the muffler. They did not recommend replacing the stock muffler and I concur.  The objective and design of the muffler are at the discretion of the manufacturer.  In the case of the 968 they went for "quieter", I could speculate on why and say its the perception that it doesn't sound like a "Porsche", so the decision was made to quiet it. Take out the resonator.  I think you'll be quite pleased with the result.

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[optigolf]

Thanks Wildcat, what you told makes sense to what I am currently looking for. I will do it possible to both of my 968s, the other one is cab and the other is -92 MO30, which I use on the track, mainly in Watkins Glen which is only hour and half from where I currently live,  'to have some fun for old bugger'.

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[flash]

it has been tested.  there is low end torque loss. you may not feel it in a tip, but you will in a 6 speed.

 

this happens with EVERY modification to the cat-back that removes restriction.  they went to great lengths to maintain a specific flow rate, including reducing collector size.  to get the torque they wanted, that's what they had to do, and it meant sacrificing 2-3hp up over 6k rpm

 

so far, the only system shown to not lose anything is the rs barn, which uses a dynomax reverse flow muffler.

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[optigolf]

Understood, so Flash what is your estimation for total cost to put super charger to 120,000 miles engine, including all needed repairs to the engine, super charger including installation and new exhaust system ? What else is needed ?

Thanks, Mark

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[94SilverCab]

Mark,

 

See this link

 

http://design1racing.com/Install_Instructions.html

 

Then, do a search here for Supercharger.

 

If you are not too old to drive by then, you might want to start assembling the parts...

 

Jay

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[wildcat]

One other thing on the tube section replacing the resonator... its wrapped with asbestos exhaust pipe wrapping to contain the heat. I don't know that its necessary but it does shield the drive line from heat which theoretically could reduce bearing life in the tube.  I noticed that resonator got awful hot in city driving and replacing it has reduced that as well. The wrap may also provide a few h.p.  I haven't tested it on a dyno.

 

On the muffler, I wasn't crazy about putting in a splitter and pressed the tech on a replacement with a single input, he said I could spend another $300 and wouldn't get a better one for the money.

Needless to say I went with the splitter.

 

Cheers!

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[optigolf]

Thanks Jay, looks like I will be too old before it is done (now 65) and moving back to Australia in less then a year. However I like to do some more things on top of what I have done to the cap as I, as many other 968 owners, like the old lady. It might be also the case that I sell both of my 968s or take them back to Australia. Or on other hand I can get with about $20,000 in Australia well set up Nissan GTR from Japan to have the fun on the track. So looks unfortunately and obvious that no go with super charger this time.

 

Wildcat, thanks again more, like I feel, usable info to what I am currently looking for my 986 cap especially.

 

Just a little side track, I might be doing one OptiGolf Center in AZ and CA and if that happens I will be moving towards your way, so you never know if we will have an opportunity to meet there. If you guys like shoot me your e-mail address to keep in touch.

Mark

m.wekara@optigolf.us

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[wildcat]

I value Flash's opinion, sometimes I don't agree with it but it is always considered, and in this case its not really whether I agree or not its more purpose or intent.  I don't know if I lose a few hp on the low end. I don't notice it at all. I'm fussy about those things too. If it gives me a little on the high end even better.  I can say that torque is not the issue, its gearing for a high torque motor. The 968 has so much torque that the Tip actually starts out in second gear with no drag or lugging.  Off the line is a bit trickier. For that one has to put one's left foot on the brake and right foot on the accelerator and pump it up to 2k or 3k then slide the left foot off.  Any loss in the low end it becomes mute. He says you do see it in the 6 speed. Well my problem with that is any restriction that produces more hp on the low end I wonder about. I wonder if its not the chip calibrated to the muffler system rather than the other way around...

 

You know where to find us... 

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[flash]

you can convince the tip to start in first.  manually, it's easy.  in automatic mode, all you have to do is stab it quickly to the floor, and it will start in first.

 

the tip revs so slowly that you probably won't notice the torque loss.

 

they tuned things for a careful balance of torque and hp (you give up one to get more of the other), and emissions.  i've played with this exhaust a LOT.  i went through about 10 variations, all with dyno tests, back when i was normally aspirated.  then another half dozen iterations once supercharged.  i learned a lot about what they did and why.

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[wildcat]

Thanks, I'm aware of the manual gate as well as the taping of the accelerator to drop the gear to first. To get off the line performance however, the technique I mentioned is the most productive. I would prefer not using the brute hp method and if the gearing of first was a little broader and second was a little shorter it might have been a little quicker.  I think however the main difference between the 6 speed and the Tip is the additional weight. I probably have dropped it by 120 lbs. Its quick but so is a Mini Cooper S. 

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