stupid question

[fitchnpolo]

With the famous "insane AWD launches" does a laggy turbo make any difference to a AWD car? would a superfast spooling turbo be unneccessary?

[Tra2xx]

Laggy turbos make a difference in all cars...

If you have a turob that starts to build boost at 4000rpm (one HUGE turbo) and you launch at 4000rpm, you will make a few pounds of boost. If you launch at redline, you will break the tranny but if you don't you will have a killer launch.

Also, my turbo starts building boost at 2500rpm but I still feel the lag sometimes, unless I am launching it.

If your question is: Do we need fast spooling turbos if we just launch them really hard? The answer is no. If we drive them daily and need spool around the streets, a laggy turbo would suck.

I'm not too sure on what your question is so there is my best answer.

[DSM_Luck]

Alot of races are from a roll on the street so a laggy turbo would hurt there. Or if you bog on a launch you will really feel the lag.

[AWD DAN]

Originally posted by DSM_Luck
Alot of races are from a roll on the street so a laggy turbo would hurt there. Or if you bog on a launch you will really feel the lag. rolling races can be saved from break boosting

[GiRLieGirL SoL]

.... no questions are stupid questions

[deadly dsm]

Originally posted by GiRLieGirL SoL
.... no questions are stupid questions

That's about right. ;) If you don't know then ask someone.

Obtaining some boost during the launch is a good thing, IMHO this is more of a free flowing exhaust thing than a "laggy" turbo.

Also, once you launch, the car won't see below 4500 rpm again unless you fuck up. Any turbo that can move alot of air at 4500 rpms of exhaust flow is a good "dual purpose" turbo.

You always hear the buzzword spool-up when people talk about lag. Spool-up, schmool-up. :rolleyes: Lag is different than boost threshold. A TO4E 50-trim comp wheel moves more air at 15 psi than a 14b at 20 psi. So do you complain about the TO4E 50-trim being laggy, not at the drag strip you wouldn't. However, in autox you would, it definitely takes it longer to go from 10psi to 20 psi than the 14b turbo would. Your turbine set-up mostly defines how a turbo gives and where it'll give it at.

Boost threshold is the rpm where you're first moving enough exhaust to get the comp wheel spinning fast enough to start making boost.
Lag is the amount of rpm span it takes to get from the boost threshold to whatever you're calling full boost at the moment.

IMHO, in an awd dsm, the launch is great and allows us a certain factory advantage. You launch at 5000 rpm or better and some decent cams will hold the airflow past your stock redline. That means you're really spinning that comp wheel when you bang second. First gear makes almost no load on the engine so as long as some boost is realized you're ok and when second starts the real boost is waiting.
So to me that means that a turbo with a boost threshold of say 3000-3500 rpm that could make 25 psi or better up here and move say 60-65lbs/min before 4500 rpm would be an instant weeklong woody.
ie: My current turbo set-up is too small, it makes usable boost before 3000 rpm and can hit 30 psi before 4500 rpm. It is maxed out, the stock dsm head can outflow this turbo and it must go, hahaha. Yet it makes some real good power and I'd recommend it to anyone worried about spool-up. ;)

[fitchnpolo]

wow, that was incredibly technical sounding and flew RIGHT over my head. :)

so let me see if i got this right, a turbo that produces well from launch rpm ->redline = best bet?

[thimages]

In my opinion, you choose your turbo based on your TOP end power goals if your a "drag racer".

You then change your driving style to suit the changed power band.

If you're a "cone killer", your criteria are different.

If you can wait 6 months for a turbo, I suggest doing so.

There some WILD things just starting to ship from at least 3 different performance turbo shops. Wait and see how well they work before you commit to purchase.

Hal