refresh951

Have heard some say pull timing to improve spool up. Others say add timing and run lean to improve spool up. Even read some stuff about pulling timing and running very rich to improve spool up. Seems to be several approaches on other boards (DSM, Supra, etc.) Anyone done any testing on a 3L with large turbo?

Tom M'Guinn

Some systems offer an anti-lag feature, which basically creates a furnace in your headers to spin the turbo (way rich, retarded spark). It creates boost when you'd otherwise never have it. Read Link's description here:
http://www.linkecu.com/support/glossary/anti-lag-def

I have not have the courage to try it -- seems like it might melt stuff in the long run.

Other guys are probably talking about more traditional tuning techniques to speed the normal spooling process, which is probably more of an iterative process for each motor...

mahoney944

Personally from running many setups I find the leading causes for a slow spool are back pressure and poor wastegates. Removing the cat with a 3 in or larger exhaust and with the wastegate dumped to atmosphere will greatly improve spool from the turbos perspective. Less pressure working against the turbo increases the spool, it's simple. With wastegates, regardless of public opinion, tial wastegates has a very fatal flaw in their design that slows down your spool time, this also holds true for the stock wastegate but for a different reason. The stock wastegate simply has a weak spring which leads to an early leaking of boost way before you reach your desired psi, which is the main reason way people decide they want to upgrade. tial uses good quality of material, but it uses the opposite side of the diaphragm to regulate the boost. At first look you may not think anything of this, however from a stock/ LR duel port point of view the boost pressure is sent to the top side of the diaphragm where it is sealed between the top cap of the wastegate and the diaphragm. This allows no chance of a leak and is considered a sealed system. With tial, the pressure is set to the bottom side of the diaphragm where the valve guide is positioned. This means when you start boosting some of the initial pressure is leaking right into the valve guide and into your exhaust, making your turbo have to work harder to reach the desired boost level, increasing spool time. In other terms, using a tial is like trying to blow up a balloon with a pin hole in it.

Ski

I guess I'm more of a fan of understanding the boost thresh hold of the set up vs. the spool aspect. I'm a KISS guy, keep it simple stupid. But, as far as tune goes, the track car is tuned at the onset of boost A/F are around 11.7-12. As the rpm increase and the butt and real dyno agree, it leans out from there to about 12.3-12.6. This worked for 354/348 @ 17psi with III MAF, 55 inj, Kokeln V turbo, LR II head, II intercooler, and 104 unleaded, with VR race chips. Now, drive the damn thing like you stole it but hit your marks