Very interesting discussion.
I am also on the same boat, currently K16 stage II and having to decide where to go next.

John, would you say your k24/18g setup with fuel has more or less lag than a k16 stage 2?

 

hly,

I would say it's very similar to the instant response of a K16/stage 2, but with a lot more power. I don't feel any lag with my P700. It's extremely responsive to throttle input and jumps to life with any throttle input - I think the added fuel and air create a more intense combustion and jumpstart everything. I was very surprised how responsive the P700 package is because I drove a K24/18G car without the fuel and could feel the increased lag over the K16/24, so I expected some increased lag as a trade-off for the added power. What I did not expect was how responsive the car turned out.

If you want a really fast car, I feel this is your best bet. The other packages are fast, but the 700 level is different. It brings you into the 130's trap speed in the 1/4 mile and 11 flat all day long, with 10's available on a good run. You can feel the difference from an 11.5-11.7 car.

 

John seriously thinking of following your above suggestions. but as you know I am a track racer not a drag racer.
How do you think your set up will hold up under hard and prolonged (90 minute) track sessions??
I was going to go with the hybrid k24 and programing. already have the vivid box, boost hoses, diverters, and straight pipes.
I will upgrade the FPR but will I need header, plenum, TB, injectors or fuel pump upgrades or can I start with what I have??
After seeing what the new 997TT and GT2 push the block I feel more comfortable to proceed to a higher level.
I will not go above 1.2 bar at the track and will stay with 93 octane.

Biggest concern is to never run lean!!

What do ya think???

thanks

tom

 

Tom,

I don't know abut the long track sessions with the 700 level. I think with the K24/18G and programming to match (600-650) you would be safe and have a very powerful car - it's just a fancy K24 at that point. You do not need anything else, except the FPR. However, I would also do the air intake pipes, port the headers and upgrade the intercoolers to reduce lag and make the most of it. Maybe the RSS TB and plenum, too, if you are looking to max out this level. You should ask Todd K about the track sessions. No need for fuel pump at this level.

Once you add the fuel pumps, injectors, etc. - the car makes a lot of power. The AFR's are fine and the boost can be set low, but even at lower boost settings, I can tell the motor is working very hard at WOT. I would guess and it is only a guess..that you would be fine with the K24/18G's without the fuel, but at the 700 level, I would not be as confident.

 

To measure boost threshold appropriately one needs to run from say 2-6K Rpms in 5th gear, and compare it against others, or vs. a stock 996TT. Any runs in lower gears will not give you the true "lag" picture. i.e. a higher boosting and modified engine will be faster than a stock 996TT in 2nd or 3rd gear from 50-75mph, whereas might be slower by 3 seconds in 5th gear.

For the race track, a good driver like T. Kerr will not encounter situations where he will be accelerating from 2k Rpms in 5th or 6th gear....so "lag" is not an issue.

I would go with the largest turbos my tuner can recommend to achieve good power levels, irrespective of how they are impacted by lag, all within reasonable levels of course.

For the track in club-racing mode, I would not call "safe" anything more than 1 Bar, and would never recommend to run a modifed 996TT beyond it. Can you run higher boost? of course, many people do, but will your engine last? You will be playing lottery.
Lowish boost, together with a large turbo setup will somehwat guarantee you many race laps with a engine in good health.

 

John, Jean thank you for your expert and experienced advise I learn alot from the real world driver guys like you.
Jean you are correct about track driving regarding lag. I have never been able to participate in those discussions because have not appreciated lag at the track. I dont think some understand that at the track you are up on boost and at or near redline all the time. so no time for lag!!
I am going to follow you guys advise. would like to run the lowest track boost I can to run a reliable 600ish hp.
I have to admit the hp of the new Z06's and 997GT3's are giving me trouble at my current hp.
upgraded k-24's and HUGE brembos going in soon!! that should do it!!! Oh yeah and just finished up a few more pro coaching lession recently and planning more with the trackmate data analysis, so hope it helps me some!!

thanks again you guys for the great input.

 

Just bringing this thread back up for the guy asking about the difference between this turbos. Lots of excellent information in here.