De-lagging a 930

[InsatiableAmos]

Hi Folks! I just picked up my first 911 this past weekend, a silver 930 w/ ~50k miles. I love the car, but it’s got some serious turbo lag! Car came with a big Kokeln intercooler and an aftermarket exhaust w/ 1 bar Tial wastegate.

I come from the rally/AutoX world where folks size down their turbos in favor of super early spool and punchy midrange. From reading about the 930, it sounds like the stock turbo is pretty old school, heavy, and inefficient. I have also picked up that a lot of folks are swapping in K27 turbos, but aren’t those fairly old school with older compressor and bearing technology as well?

Is there a widely accepted solution for reducing lag on a 930? Not looking to make much more power, just looking for better response and more boost in lower RPMs…

[Jim2]

Congrats on your purchase, many people don't have the means to buy a 930 since prices have increased.

You are dealing with an old car with antiquated technology. Poor turbo, poor cams, poor intake manifold, and to top it off 7.0:1 CR. Also the gear spacing is rather wide. I'm not in a position to make a turbo recommendation but you are on the right track, maybe also consider a ball bearing unit and a tighter turbine housing. Of course it will plug up the top end but it will reduce lag.

Other members need to chime in with more ideas.

[DaytonaCoupe66]

I'm getting on in years so I find the stock setup to be just fine on my '82, including the tall gears. I kinda' like the lag and the challenges that go with. If you do a search on Pelican there are several well informed enthusiasts who have contributed a lot of technical narrative to the theme of your question. While you await a response, the general bits of information are easy to find. Cheers!

[RarlyL8]

Pretty bold first air cooled 911!
Good news is these engine respond incredibly to bolt-on modification. Replacing the exhaust system with properly designed headers, free flowing muffler and K27 or modern turbo will knock the lag down 1000rpm and add as much as 100hp or more depending on the engine. Add a larger intercooler for even more free power plus allowing safely increasing boost level a few tenths of a bar.
The engine will run cooler and drivability is greatly enhanced. All these parts bolt on allowing you to easily swap back to stock should you desire to do so. When we do these upgrades the stock parts are cleaned up and boxed up for long term storage as they typically never go back on the car.

[slow&rusty]

InsatiableAmos - Congrats on your 930.

What year and please post some pictures.

RarlyL8 nails it with his reply and recommendations. His products are also top notch.

[gassian]

i would suggest exhaust and possibly changing turbo compressor blade to billet with 6-8 fins would help

[krasuskyp]

Congrats & welcome!

Echoing others above (esp BrianB!)... you've already got 2 of THE biggest contributors toward lag reduction on your car (Kokeln is one of the best flowing & cooling / exhaust... which?).

From here, headers would be my very next step - MASSIVE improvement in drivability and lag reduction there. Then, any form of more modern snail of your liking. Research here for best options, but most commonly seen are K27-7200 (w/ the Raptor upgrade etc), Borg Warner, and GT35.

That should get you to where you're happy... if not... welllllllllll, welcome to the long steep & FAST / INFINITE slippery slope - muwhahahaaa. You DO need to adapt your driving style *considerably* from that of autox tho fersuredly... takes awhile and much finesse / practice certainly - but once achieved, it's quite a delectable experience!

Good luck, report back - and... oh yeah... can't post here w/o PICS!!! 8 )

[908/930]

Are you sure everything is set up correctly with your car to begin with, is Ignition and fuel system working well and set up properly? What turbo is in there? Also what year?

[flightlead404]

Not sure on your intercooler, but if it is a "short neck" design and uses the intermediate manifold aka BOV housing then that extra volume to pressurize before the TB will add a little to lag as well.

Consider a long neck and get rid of the old-school BOV.

I would also verify ignition timing, that can have a huge impact on the responsiveness of the engine. Is it a stock dizzy or something else?