Appauldd

iTrader: (22)

Being the torque junkie that I am, I am curious as to what others do to try and get their turbo to spool faster.

My car does not like a lot of timing and prefers to run a little lean. (93 octane only)

I am able to have my Green spool to 27PSI by 3500 rpm by having high 12s in fuel and timing that goes from 20* at 2750rpm 100 load then quickly tapers down to 6* by 3000 rpm 200 load. And to 4* at peak boost/load at 310ish.

The fuel then tapers to high 11s tapering to low 11s by redline. Timing then tapers from 8* down to 4 to 5ish depending on load.

I am fighting boost taper as best I can.

Please discuss.

Paul

THE RESULTS

l2r99gst
The turbine is driven by a pressure differential pre and post turbine. That is where the exhaust 'energy' is coming from. Increasing heat increases pressure (PV=nRT), so retarding timing and increasing EGTs increases pressure pre-turbine and spools the turbo faster.

Anything that can increases the pressure pre-turbine or reduce the pressure post turbine will help spool.

Top 10 notes for FASTER SPOOL

1) Less timing (Start with stock values during spool, tune from there)
2) Richer AFR (mid 12s during spool to max boost, then taper richer)
3) Hot pre turbo exhaust
4) Port head, manifold, turbo, O2 for more flow
5) Free flowing exhaust
6) BOV leak free
7) Free flowing, low pressure drop, high efficient FMIC
8) Waste gate sealed shut until peak boost is achieved (Higher tension)
9) Shortest intake pipes as possible
10) No boost or vacuum leaks

NightCat

Do you already have larger Intercooler piping and or an upgraded intercooler?

Appauldd

iTrader: (22)

Yeah...my intercooler is larger and I have full HKS pipes.

Appauldd

iTrader: (22)

So no one cares to discuss spool ? ?

sub7

I think faster spool doesn't always go with tuning alone. It's true lean + safe afr at 12ish make spool come faster, advancing cam intake by 2degree does make my gt30 spool 200rpm earlier.

Appauldd

iTrader: (22)

I think porting helps a lot with spool too. More flow is always better I suppose.

l2r99gst

iTrader: (2)

Anything that will help inrease the pressure ratio pre to post turbine will help spool. Usually with tuning you can do it by increasing heat in the exhaust with less timing.

But you also have to keep in mind that a lower RPM spool doesn't necessarily mean a faster spool. For example, you can retard your timing a lot and get your turbo to spool, let's say, 300 RPM sooner. But that decreased timing also takes longer to get to a certain RPM as greater timing would. Hope that makes sense.

Basically, it's not just the RPM that you spool at, but how much actual time it takes to get to that RPM.

Appauldd

iTrader: (22)

Good point! I am sure there is a point of diminished returns when it comes to spool. Any certain turbo is only capable of spooling so fast and so soon. Tuning for the best case scenario is what I am trying to accomplish. Fast and early spool and boost that holds till redline. That is the ticket.

racer135

iTrader: (2)

27 psi bty 3500 is preety good for a green. What do you mean by timing tapers from 8* down to 4 or 5???? Your timing should go up with RPMs. You sauid that you run 4* at peak load so I guess you are not talking about timing tapper at peak load.

I am also trying for ways to reduce spool and increase timing at high RPMs. What timing are tou running at 8K PRMs?

Appauldd

iTrader: (22)

Timing should taper down until you hit peak load, then timing should increase as rpm increases.

As for top end I am running between 12* and 15* depending on load.

03whitegsr

iTrader: (8)

Doing what makes the most power will make the car the quickest.

Everything else just gives up power and acceleration for the appearance of a faster responding boost guage.

This is why I fully tune the car at every load I can hit. The tune is more or less perfect every where and the repsonse is unbeatable.

Appauldd

iTrader: (22)

Agreed.....but what can be done to increase turbo performance? How can timing and fuel be used to achieve best torque, fastest spool, and best holding ability.

I am just playing devils advocate here....I get a ton of PM's on these topics. I just wanted a place of discussion for others to follow.

We all know every car is different. I posted how I do it in my situation. The car pulls like hell. So much that I can't "play" in lower gears without spinning the tires. It just wants to go!

honki24

iTrader: (23)

I didn't read everyone's posts, but

Cam timing.

There's some guru on here that posted a great thread... I think it was like BTed or something like that. If you do something like +2/-1 you'll notice a HUGE peak torque jump versus the standard -4/-1 settings. Of course I'm talking about an 8 where I don't have VVT.

Edit: maybe his name on here was TedB...

I used to run this config. and it was GREAT on the street... but for the track I use more of the upper RPM band now and shift less so I'd rather the high end HP over the punch in the stomach boost kick torque. More smooth power up top is usable where sharp and abrupt torque at apex is.... disruptive.

daymean

iTrader: (2)

Would love to read that post....I love the feelin of toque but struggling with an 8 here that gives me more whp than tq...
Does faster spool usually equate to higher tq values?

sub7

The more timing your car can take, the more tq it produce (richer afr) at higher rpm. Leaner afr produce more hp and faster spool.