Spool time and exhaust

[JohnT]

Has anyone taken the time to log spool time with aftermarket vs factory exhaust. Maybe a few rpm vs boost graphs starting at idle, 2k, 3k, etc.

A couple people have mentioned increased lag/spool with aftermarket exhausts. I would think it should only spool faster with less restriction? Velocity through the turbine should only be increase, no? Less pressure downwind but that seems irrelevant....

I ask because as an autocrosser utilizing the OEM tune (without making more power) the last thing I want is slower spool!

 

[Eric Smit]

the bigger your exhaust, the faster you spool.


-Eric Smit

 

[sx sonic]

+1. I got a small but noticable decrease in spool time with my catless down pipe.

 

[JohnT]

the bigger your exhaust, the faster you spool.


-Eric Smit

That's what I always assumed, but Laborsmith and Thaifight-R have both mentioned in other threads slower spool...possibly an tuning problem?

 

[Eric Smit]

That's what I always assumed, but Laborsmith and Thaifight-R have both mentioned in other threads slower spool...possibly an tuning problem?

I don't remember reading that, but the faster the exhaust can blast through the turbo, the faster it spools. just physics.

 

[JohnT]

I don't remember reading that, but the faster the exhaust can blast through the turbo, the faster it spools. just physics.

http://www.sonicownersforum.com/forum/post22370-13/

and

http://www.sonicownersforum.com/forum/post24755-10/

Obscure, but with more than one mention I wanted to know what going on

 

[Eric Smit]

well, I guess they did say that, but I still maintain that a larger exhaust will only decrease spool.


-Eric Smit

 

[duhveed]

The turbo is peanut sized spool time is the last thing I worry about in this car lol

 

[sx sonic]

ZZP mentions faster spool time for their downpipe on their website, i suspect they are in the know.

 

[pwntbywombat]

I have insta spool with my 3" turbo back. 1400 RPM, riding through a tunnel, give it a bit of gas, and it spoils like a turbo diesel.

 

[slitzell]

I think the exhust lowers the low end torque just a lil bit, but when the turbo starts to spool, its spools faster giving you that oomph feel thatblaborsmith was referring to.

 

[Eric Smit]

I think the exhust lowers the low end torque just a lil bit, but when the turbo starts to spool, its spools faster giving you that oomph feel thatblaborsmith was referring to.

good thinking. that could be it.


-Eric Smit

 

[laborsmith]

That's what I always assumed, but Laborsmith and Thaifight-R have both mentioned in other threads slower spool...possibly an tuning problem?

I don't remember Laborsmith nor Thaifight-R posting that.

Laborsmith

 

[Eric Smit]

he posted links in post 6. http://www.sonicownersforum.com/forum/showpost.php?p=121271

you're the first link.


-Eric Smit

 

[pwntbywombat]

I think the exhust lowers the low end torque just a lil bit, but when the turbo starts to spool, its spools faster giving you that oomph feel thatblaborsmith was referring to.

The turbo itself will create more than enough back pressure for the engine. The name of the game with a turbo car, is get the air in, keep the air cool, and get the air out. All as quickly as possible.

 

[laborsmith]

So much for my memory.

The "oomph" sensation remains although I no longer attribute it to slower spool.


Laborsmith

 

[Mobius97]

The turbo is peanut sized spool time is the last thing I worry about in this car lol

Exactly what he said.

 

[slitzell]

So much for my memory.

The "oomph" sensation remains although I no longer attribute it to slower spool.


Laborsmith

Memory fades with old age lol

 

[pwntbywombat]

Exactly what he said.

Now now. The laws of physics still apply. The easier the air comes in and the easier it leaves, the faster it spools.

 

[Eric Smit]

and I can start spooling at 1000 RPMs in sixth. physics rule!


-Eric Smit