Popping Exhaust

[n52]

Hi All,

Just bought myself a japspeed exhaust (decat) for my N/A I like how grumbly it is and when its hot it will have the occasional pop. I was wondering if there is any way or anything I can do to it to make it pop a bit more frequently?

Only reason I ask is my friend has a 1,8 celica cat back exhaust with a 3" rolled tip, the thing is alot quieter but it pops a hell of alot more than mine?

[CalMac]

Heat wrap

Also I've heard that you can thread the tip of a sharpened screw into the exhaust tip and it will get exceptionally hot - making pretty flames

[n52]

I was looking into heat wrapping the downpipe etc, does it really work that well?

[CalMac]

It should help, can't say from experience though as my engine went bang shortly after I heat wrapped mine from the block back. I was using a Japspeed mani and mid pipe.

The only other options you've got are to mess with the fueling, add a turbo or use smaller diameter exhaust. I'm guessing you've already de-catted? Obviously that will make a big difference.

[Draven]

I get lots of pops on overrun when the car is nice and hot. I'm not sure there is a way to make it pop more.

[n52]

It should help, can't say from experience though as my engine went bang shortly after I heat wrapped mine from the block back. I was using a Japspeed mani and mid pipe.

The only other options you've got are to mess with the fueling, add a turbo or use smaller diameter exhaust. I'm guessing you've already de-catted? Obviously that will make a big difference.

Did you wrap yours in a certain way? I.e. spraying before wrapping or did you just wrap it all up straight off the bat?

[cosmos]

Try supermarket fuel !!

[CalMac]

I just bought tonnes of Titanium wrap off Ebay with stainless cable ties and did the whole lot right up to the first backbox hanger (Nur spec)

[bobhatton]

I just bought tonnes of Titanium wrap off Ebay with stainless cable ties and did the whole lot right up to the first backbox hanger (Nur spec)

That is a great way to lower you power output

[CalMac]

Can't really see how increasing exhaust velocity would decrease power output.. But I'm interested to hear your opinion Bob?

[n52]

Can't really see how increasing exhaust velocity would decrease power output.. But I'm interested to hear your opinion Bob?

Second that

[Draven]

I'm not sure how it would on a turbocharged engine. At worst i've heard wrapping the downpipe can cause them to crack.. but no power issue.

[Ren0W]

I used to pop (more BANG!) by flooring it to around 3-4000RPM, foot of pedal, let it drop to around 2-2500RPM and tap the pedal.

Every tap it was BANG BENG BENG BANG.
Could tap it around 5 times.

This was on my turbo tho, with a 3" NurSpecR, which made extremely loud bangs.
But yea, you could try it.

(didn't need my engine/exhaust to be hot before doing this trick)

[Gullzter]

I used to pop (more BANG!) by flooring it to around 3-4000RPM, foot of pedal, let it drop to around 2-2500RPM and tap the pedal.

Every tap it was BANG BENG BENG BANG.
Could tap it around 5 times.

This was on my turbo tho, with a 3" NurSpecR, which made extremely loud bangs.
But yea, you could try it.

(didn't need my engine/exhaust to be hot before doing this trick)

Done this myself, decat and SS system is what you want to do it. Im pretty sure it also happens when you run too lean not that its a good thing!

[Slarty]

That is a great way to lower you power output

Strange that the WRC cars wrap their exhausts most of the way through. They obviously don't know what they're doing.

[Marf]

I just bought tonnes of Titanium wrap off Ebay with stainless cable ties and did the whole lot right up to the first backbox hanger (Nur spec)

That is a great way to lower you power output

Bob, you clearly have some reasoning behind this, why not explain it rather than just making a terse comment?

[n52]

I tried the slow gear changing last night, seemed to make it pop the few times I tried it.

[CalMac]

I find that when cold if you drop gears without rev-matching then it'll pop more frequently, however if the exhaust is properly warm (maybe 20-30 minutes driving) then you'll get pops and bangs even on upshifts. Or at least I do in the Scoob lol

Rolling down a hill in 2nd at about 45mph will do the trick as well

[ashley]

In theory wrapping the exhaust on an NA car will keep heat in the exhaust gas and increase the scavenging effects from the cylinders, and in effect increase power.

In theory in a turbo charged car, wrapping the exhaust after the turbo will keep heat in the exhaust gas, and as a result increase back pressure on the turbine. This reduces the pressure gradient across the turbine, and will reduce maximum power levels achieved.

In an MR2 however, will wrapping the exhaust of a turbo charged car reduce the temperatures in the engine bay, and so allow colder air to be ingested by the compressor and actually increase power?


Did I stress in theory enough?

[Odin_S]

Not wanting to getting into the handbag fighting but i've noticed this alot on this forum. Why do you guys jump down bobhatton throat when he gives tuning advice? Maybe not a lot in this particular one but other i've seen.

Not in one of his cheer leaders but i found he has good knowledge on these engines and engines in general

Ok he does go on about Chinese products a little too much but we all have our problems