Garage Storage Organization and Garage Cabinets

Michael_Valentine · 07-19-2007, 03:19 PM

If it comes off easy enough, then yes! I might even opt for a 3" at that point. I will tinker with it this weekend and see if they want to budge, if not it stays on. My current downpipe (stock) has a very nice dent in it from a previous mishap I assume so replacing it would be necessary!

87dtna · 07-19-2007, 03:33 PM

OK you weren't the thread starter, I realized that just now.

Michael_Valentine · 07-19-2007, 04:05 PM

No, just trying to get some more info on the subject.

**crazymadbastard** · 07-19-2007, 04:39 PM

Quote:

Originally Posted by Michael_Valenti

Thanks, what is the best way to remove the swing valve, from underneath or from the top? Nothing more than basic hand tools required..correct?

Underneath is the way, I think if you pull the pass side wheel you can get at the bolts with a 13mm socket and extra super duper extra long extension.

Michael_Valentine · 07-19-2007, 11:35 PM

Thanks, I will see if they come loose this weekend. Hopefully I get lucky and can go for the 3" setup!

Reaper1 · 07-28-2007, 10:13 AM

I dissagree that you won't see a gain with a larger DP on a 2.25" SV. Turbo's work off of a pressure differential. The greater and faster you can make this differential, the better the performance from the turbo. Not only in the ultimate power it can make, but also in spool up time(area under the curve...which is VERY important). The faster you can releive the backpressure on the exit side of the turbine, the easier it can let the gasses out and the better it will work. Yes, the 2.25 SV is STILL a restriction, BUT you releive that restriction after it and you WILL see an imporvement! IT wno't be as much as with a larger SV, but it will still be enough to make a difference that IS noticeable. I'm running an '88 2.25" SV with about 4" of '89 2.5"DP and then it flares to 3" pipe.

Besides, what were people doing before the 2.5" and 3" SV were more widely available? They were running a larger DP or a cut-out.....hmmmmm

86Tona · 07-28-2007, 09:38 PM

Quote:

Originally Posted by 87dtna

So you are replacing the swingvalve too or what? If you aren't putting on a 2.5'' swingvalve than replacing the factory downpipe is a WASTE OF TIME and effort AND money. The factory downpipe is 2.5'' at the cat, and you will see NO GAIN whatsoever by all this work to put a 2.5'' downpipe on a stock 2.25'' swingvalve.

Sorry but there will be an increase in performance with a larger pipe on the 2.25" swing valve. In fact there will be a marked improvement. Remember on the '86 at least the pipe has an inside diameter of 2" or less not to include the crimp bends which reduce the diameter more. BTW, since I started this topic nearly a year ago I've gotten the trubo ready to go on the car. It does indeed have the 'stock' swing valve for the later turbo (not '86). The swing valve has been ported. I've been told that the actual diameter (inside diameter) of the 2.5" swing valve is just at 2.3" while the 2.25" swing valve also is slightly under 2.25" too.

But the trick is to open it up. In my case the stock 2.25" swing valve was opened to 2.4" which is more than the 'stock' 2.5" swing valve. I got this information from my head porter. Since my 2.25" swing valve is no longer 2.25" but 2.4" and since the pipes will be 2.5" I'm hoping for some great performance from this setup.

But I digress. You said that putting a 2.5" pipe on a 2.25" swing valve will NOT result in an improvement. I read an article somewhere which stated that the best 'flow' out of a turbo is that of well....... it's like a trumpet horn. So if the turbo started at say 2.25" out and then gradually opened to say 2.5" at 12 - 18 inches out it would do a great deal in flow dynamics to help evaculate the turbo. While this is not the optimal 'angle' of widing it will serve to offer a good improvement. So what I'm saying is this for a stock setup. If the down pipe started at 2.25" and say widened gradually over about 12 inches to 2.5" this 'horn' would actually improve the flow better than simply slapping on a 2.5" pipe at the donut.

Of course when I do this I will include a high flow cat and muffler as well as pipes from the swing valve to the tail pipe tip all mandrel bend and 2.5".

The improvement from such a small diameter change well actually not so small. Going from 2" crimp bend to 2.5" mandrel bend is a big difference in the pipe's ability to flow. In any case this difference 'will' make a big improvement in performance especially when coupled with the ported intake, exhaust, swing valve and head.

A big difference.