Running with pipes off

[paddy351]

Hi guys just wondering about running at heathcote with the pipes off my xw. I have herd that you gain power but you could loose torque and how does it alter your tunning. Thanks -Pat

[jcxr]

Sometimes its handy to be able to hear your engine, to get shifts right, so open pipes are a bonus in that way.

[forcd6]

Probably a good thing that you throw it up on the dyno with the pipes off to make sure that your not leaning out before you race it a Heathcote. Might save you a motor.

[blueprintxr]

id be happy to be there to hear it reguardless :p

[capriv8]

I gained three tenths in the Mustang with the pipes off, 10.90 down to 10.60, I didnt make any other changes also the sound is awesome at 7000 rpm running through the finish line.

[paddy351]

Thanks for that fella's

[nugget378]

Forget dyno's,the way I would do it is have a couple of runs pipes on first,then drop the pipes and see what it does,I know of more than a few instances of street cars going slower pipes off..
It really amuses me when I see guys with 400hp engines rock up and immediately drop pipes,all the while never knowing if they gained anything,except a maybe slower 11 or 12 second car that now sounds like a top fueller..

My last car went just as good pipes on..and sounded better IMO..

[xr8 5.0]

My xr8 goes harder with the pipes up , 2 tenths quicker

[paddy351]

thanks nugget and xr8 5.0 i will try both .

[Barry_v]

with the helmet on and a open pipes car next to you its impossible to hear your own engine if you leave the exhaust on.

[nugget378]

Originally Posted by Barry_v

with the helmet on and a open pipes car next to you its impossible to hear your own engine if you leave the exhaust on.

Its something you do get used to,I listen to the tone of the engine rather than the exhaust,but mostly keep an eye on the tach.

[ClevoCapri]

I gained from dropping the pipes. From a 10.9-10.5@127mph. I do have a rather crap exhaust though. It goes from 3.5inch collector to twin 2 1/4 into a single 2.5inch.
So i guess if you have a decent exhaust you shouldnt expect too much improvement.

[paddy351]

I run 4-1's ,3inch duel into 3inch single pipe.

[gregaust]

Originally Posted by paddy351

I run 4-1's ,3inch duel into 3inch single pipe.

That should be plenty of exhaust. Be surprised if that makes a difference.

2-1/4" pipes on a 10 sec car,not surprised it went faster..

[ToddZC]

My old silver barge ran the same with pipes on or off, but then again it had a nice exhaust. Dual 3 1/2" from the collectors to through the mufflers. It made it hard to hear the engine at idle when the car next to you ran an open exhaust, but once the engine was revving I could hear it okay.

[TruBlu351]

Originally Posted by ToddZC

but once the engine was revving I could hear it okay.

That's because the barge was now way out in front!

[TruBlu351]

Originally Posted by paddy351

how does it alter your tunning. Thanks -Pat

May trend towards the leaner side with pipes off, so you may need to fit slightly bigger jets..........looking for max mph.

[xdclevo]

I gained 3 tenths when i dropped the twin 3" dumped at the diff, and ran extractors only. Looking at the plugs, it didn't seem to change the tune any noticeable amount.

I did have the 750 Demon modified so that would contribute a bit possibly too, so not sure what exact gains made.