Ok I'm running jet hot LT's With an x pipe and bullet mufflers with putting 3 inch pipes cause problems with back pressue or should I stay with 2 1/2. I'm also running these back to the rear end and dropping them there.

Do you think I'll have clearance problems with eibach pro springs?

 

depends on your goals - if your planning on hitting 400-450HP or so, you might be better off with 3" pipes. Less than that and your probably better off with 2 1/2. There is such a thing as too much exhaust

check this out:
http://www.dynomax.com/techsupport.stm

 

you'll be fine with 2.5"

 

i have the jethot longtubes, hotcam and 3in true dual with dynomax bullets that dump just before the rear axle, i think it may be a little too much exhaust for under 400HP, and Geez is it loud as hell.
very very loud, stock car loud, couldnt talk on the cell phone if you had to loud,
get my drift?

Chris

 

I went with 3" duals but Im expecting quite a large amount of HP with my stroker.

 

and i do think you will have problems with the eibach pros

 

Heck, I have occasional problems with my stock springs

 

No way with a lowered car.. I dunno if 2.5 would even fit. Every time I see another 2.5 vs 3 inch thread I think I wish someone would have told me is "use some oval piping" I think that would help clearance a lot. I also use really long bullets.. I believe they're 30 or so inches - not too loud unless you get on it

 

Question is.... where is the clearance problem?
Is the problem actually the exhaust diameter or the collector??? I don't have my car together yet but that's the question as I see it. If you have a clearance problem with the pipes then yeah, oval is the way to go. If it's at the collector then it won't help much.... gotta fix the collector.

-Mindgame

 

Well, when I bend/crack the collector flange then I'll just cut that sucker off and use a band clamp.. the flange does rub but the pipes will also esp. if I go quickly over a speed bump. When the car comes down the pipes whack on the bump.. I think some of this may be alleviated by new springs and shocks/struts.. car has 90,000 on it or therabouts.

To clarify, I think the best clearance you could get would be with the jethot headers (they use a band clamp don't they?) and oval piping.. dumping before the rear axle of course.

My .02

 

They may, I dunno for sure.

I always use a different collector (most factory collectors are shorter than really needed) and never use a flange. Slip-on/band clamp is the way to go and you're right, you get a little more clearance there cause the flange is usually what ends up scraping the ground.
Oval will give you more clearance. I still haven't gotten the motor in the car but I'll be looking at this within the next few weeks, may be going oval myself but have to wait and see. My car's about an inch lower than stock and I'm running long tube headers. We'll see.

-Mindgame

 

I have been considering the oval pipe idea for a long time. My main question is, does it flow the same? At first I thought yes, but after talking to a friend who is about to graduate as an engineer, he says no.

 

i don't know how you guys drive your true dual cars anwwhere. I just finished my 3" true dual, and I shoved that @#$% up there as far as I could, and I can't go anywhere with the thing. Heck, i bottomed out on the freeway yesterday and put a fat dent in my x-pipe. Now i have to go and redo it, or get a catback or something. And yes, my car is stock ride height.

Did people who do this get rid of their cross brace or something?

-Chris

 

If the duals are made/fabbed well, the collector will be the lowest point. That was the lowest point on my entire exhaust and that was using 3" tube on the duals.

 

ummm.. yea.. you need to remove the cross brace. That would probably fix a lot of your problems How much clearance do you have with the x under the brace? an inch?

Do a search and take a look at some more pictures..