GDP twin tip exhaust installed, one issue

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Richard Holler
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Tag: 1963 356 S T6 coupe
Location: Chicago, Illinois

GDP twin tip exhaust installed, one issue

#1 Post by Richard Holler »

Seems to sound fine, Since the exhaust is more visible now, I did notice the exhaust hangs down a bit more on the passenger side? Is my engine sagging somehow? transmission mounts? they are original...

I'll get a pic up later today...
1963 356 S T6 Karmann Coupe (stock engine)
Front disc brake conversion
GDP Dual Exhaust
Momo Classic steering wheel
SMD headlights
CUlayer LED rear tails
Superleicht spec (aka missing V brace and copious amounts of Bondo)

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C J Murray
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Re: GDP twin tip exhaust installed, one issue

#2 Post by C J Murray »

That could be many things so measuring everything is the only way to find out. You can also use a level on the sump, the muffler, and the body.
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Dick Weiss
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Re: GDP twin tip exhaust installed, one issue

#3 Post by Dick Weiss »

Richard,

If the trans mounts are original, Most likely their oil-soaked & squashed from age. Also, the twin-pipes should be in line w/its neighbor,
but hopefully the body's underside hasn't been repaired from any previous damage.

Dick

Richard Sutliffe
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Re: GDP twin tip exhaust installed, one issue

#4 Post by Richard Sutliffe »

I installed the GDP sport muffler on my '65 SC a few weeks ago. I helped a pro friend with a lift and although the lift makes a nice difference in ease of install it's not necessary. You could do it in your home garage without much trouble. I replaced the original stock muffler. I handled the issue of the exhaust body cutouts by installing front bumper guards on the rear to cover the holes. They do the job and also look cleaner IMHO. The GDP is beautifully built and fits great. The sound is a bit disappointing as I was hoping for a little more noise. Yes it's a bit louder and deeper, but not enough to justify installing it for that reason. To me it sounds pretty much like the stock muffler. It's about 6 Lbs. lighter than the stock muffler which represents about a 25% decrease in weight hanging out over the back of the car. Performance is fine. It seems pretty similar to the stock muffler. It would be nice to see a dyno comparison. Am I happy with it? Yes. I don't plan to go back.
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James Learmonth
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Re: GDP twin tip exhaust installed, one issue

#5 Post by James Learmonth »

Richard
Nice but it looks like it hangs down a little on the passengers side.
Jim

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John Clarke
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Re: GDP twin tip exhaust installed, one issue

#6 Post by John Clarke »

Hi all
SO, both Richard Holler and Richard Sutcliffe seem to have there GDP exhaust lower on the passenger side! Strange!
Is the GDP a stainless steel system? If it is, it probably accounts for the slightly increased noise levels.
And Richard Sutcliffe, where did you obtain your front bumper overiders / guards for the rear (upside down)? It's a brilliant way to get rid of the holes left by the stock tailpipes. been meaning to do that for a few years now since installing a Bursch system, but have never come across a pair of front guards!
Cheers Jay
 

Richard Sutliffe
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Re: GDP twin tip exhaust installed, one issue

#7 Post by Richard Sutliffe »

James. I'm not sure where you see that the GDP exhaust hangs down on the passenger side. To me it looks perfectly even and level. Regarding installing the front bumper guards without the exhaust holes on the rear to cover the exhaust cut-outs in the chassis...that was my plan. I looked at used fronts, most were trashy and not cheap so I finally bit the bullet and spent $280 on a new set of Dansk's on EBay. They arrived in perfect condition and went on without a problem. Regarding the lack of over-riders, I deliberately took them off when I installed them. I wanted to try out a cleaner look. I'm not sure I'll run with this look long term but for now I'm staying with it. Re: the small holes...plug them with 1/8" (I think...measure) black plastic plugs from ACE Hardware. Finally. Yes the GPD system is totally stainless and a work of art.
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Last edited by Richard Sutliffe on Tue Oct 02, 2018 4:54 pm, edited 1 time in total.

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John Brooks
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Re: GDP twin tip exhaust installed, one issue

#8 Post by John Brooks »

I just helped install one. Had a similar list. Go feel the top 2&4 header pipes, where they pass under the pinch welds at the rear of the body. On Toms we had a 1-2mm interference on the passengers side #2 pipe.

Easy fix with a little hammer work, to make a radius in the seam for clearance. Split the seam open to access each side. Fold the front inner liner forward and the back one aft and radius out it centered on the pipes. Toms now looks like it was designed that way.


i thought it was from a previous collision repair. But after relieving the interference the tips were even.

Edit.. Went over to Toms an took a photo, also found no clearence on the full flow oil filter heat shield that I missed before. It's tight, if you have a PM full flow pump mounted filter, you will need to make a dent along the 2:00 front in the new muffler it to get some More clearence. Fits 3mm without the heat shield.
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Bends in the aft apron over cyls #2&4 outlet pipes. Double check the PM oil filter clearence
Bends in the aft apron over cyls #2&4 outlet pipes. Double check the PM oil filter clearence
John Brooks

62 Roadster
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getting pushed around in porsches since 1965

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