One thing I'd point out - while more power is "great" it's not so hot if it leads to expensive breakage. Halfshafts, transmissions, and things like engines can be depressing to replace. Nothing like strapping on a new part and snapping something testing it leaving the driveway. Or finding that you lose traction at highway speeds when the turbo spools up I try hard to keep that in mind having gotten a nasty surprise a time or two - both of those situations actually. So this leads to a question of what's sane and safe. Elsewhere I'm told 700 flywheel HP without going into the motor, rest of the drivetrain sounds fine. Seeing drivetrain loss figures as high as 25% quoted here and there that makes for a somewhat depressing WHP limitation. Wouldn't a K24/18 surprass that?

Hi Steve!

 

You are pointing out the obvious. There are numerous members running 24/18s without snapping halfshafts or having transmissions problems. I also haven't heard of anyone having problems losing traction at highway speeds. Not saying it hasn't happened, just that I haven't heard of any. Obviously, there is a limit to how much power these cars, or for that matter, any car can take before something breaks. From my experience, using the 24/18s with a FPR and a new clutch is not a problem. Sounds like you are talking about adding power at the extreme end. That's not what we are talking about here. If you've followed the many threads posted regarding the installation of the 24/18s you'll know there hasn't been problem with this car's ability to handle the additional HP.

 

You've misunderstood me, I wasn't speaking specifically about this upgrade but more so the "if some is good lots more is better" sort of comment. It's been my experience that at some point things become just silly and dangerous. I once helped tune a particular car destined for the dragstrip - full tubbed chassis blah blah but first turbo install. It made so much more power that it had to be turned WAY down just to make a clean pass. Likewise a friend's Honda. FWD and big power was just stupid, even with slicks it pulled for the wall as soon as power came on. Both thought that having "more" was the way to go - both were north of 700WHP too. I ran into this some myself with a car that made big power but on pump as a driver it was less than ideal - mostly due to turbo lag and a power curve that jumped 100+WHP in just a few hundred RPM. I was actually going to move to a much smaller turbo just to see if the additional power under the curve made it quicker around town on pump gas. <shrug> Yes, that car spun tires at highway speeds if I was stupid. I wouldn't expect that to be likely in an AWD 996 which is a great deal of the reason why I'm interested in one - traction! Some of the drag tests the car mags have done in the past with highly modded Viper Corvette etc. have sort of proven this point as the drivers could barely make it down the track from a standing start. But hey they had 1K+ dyno sheets...

From everything I've read thus far the 24/18s sound pretty ideal and not over the edge for driveability. Pretty balanced and not so small that it will run out of breath as RPMs rise under reasonable boost. If 700BHP is indeed a sane limit for these engines in stock config how hard is the 24/18 setup likely to push it with supporting fuel and clutch? Filling out Steve's chart with WHP figures would really help...

 

Steve, I understand and agree with your points and they are all valid. My comments were directed at the difference in power between the 16g set up and the 18g turbos. I should have been more specific. Sorry if I misunderstood.

 

[quote=Steve Theodore;2352300]This thread is becoming more and more useful for those of us new to the community. Could we now go on step further and classify the same list by "rough" cost and possibly expected awhp (or even rwhp) figures?

Okay I will take a stab at this one. I went with Crank HP #’s for now, there is so much variations between different Dynos. So this should give you a rough idea of what is needed.

K16 stage 2 –
500 Crank HP level
Flash cost: $1000 – $2500
Exhaust: $1600 - $5000


K24 flash – 500-550 Crank HP Level
Flash cost: $1000 – $2500
Exhaust: $1600 - $5000
K24 Turbos used: $1700- $2000


K16/16g – 600 Crank HP Level
16 G Conversion with 1 bar wastegates: $1200
Flash cost: $1000 – $2500
Diverter valves: $150 - $300
5 Bar FPR: $150-$300
Most likely Clutch will go after some time, so Clutch: $1300- $1700, Labor: $1200 (Independent Shops)
Turbos Install: $500 (6 hrs at $80 /hr)

K24/18g – 650 – 700 Crank HP Level (Injectors get you to the highest level)
K24 Turbos used: $1700- $2000
18 G Conversion with 1 bar wastegates: $1200
60lb Injectors: $500 - $600, Install Labor: $ 800 (Motor Drop Down)
Clutch: $1300- $1700, Labor: $1200 (Independent Shops)
Turbos Install: $500 ( 6 hrs at $80 /hr)

 

[QUOTE=vbmw335;2352703]Great info, thanks! One question though, if you gain so much out of the k24/18g, why would people pay 10k+ for gt turbos that gain less?

 

Where did you see that the GT turbos make less power than 18g? also they are not 10k. They have the potential for making more power but to make it safely most go for an engine bottom end redbuild above 700 hp level.

In my opnion the 18g's are the best turbo's out there to get to 650-700 hp level. The GT's are high quality turbos for sure but arent direct bolt on like the k24/18g.

 

The new GT3071 and GT3076 from Tial are bolt-on and both make WAY more power than the 18G.

 

Thank you very much vbmw335...reps to you!

Hi BLKMGK...long time, no see old friend.

 

You are correct...I just got off the phone with Tony...he has found another enticing option to lighten my wallet.

 

I read on Evoms' website that the GT610 package is 13,000$? While only producing 610 crank hp? Sorry, I'm pretty new to turbos as well, could you please explain this to me? Thanks.

 

I dont think its really that much if you already have the exhaust and the DVs. I paid ~7K for turbos, program, oil lines, and hitachi maf/v-flow intake.

 

Okay, sorry to beat a dead horse here, but here's a clutch question. Are we generally speaking about using the same clutch for 16/16G as 24/18G, and would it be okay to use that with a stock set-up? What I'm considering doing is buying the upgraded clutch now, swapping it in the next time I have the engine out for any reason (I'm due for plugs soon..), and then either going to 16/16G at the same point or soon after. Or 24/18G if I can be persuaded I'm not a significantly higher risk of making my engine explode by doing so.. (I also don't really ever want to use race gas...)

What particular clutch/clutches would one use for these kits, and how does their driveability differ from stock? My car is mostly a daily driver. I'm going to go look at exact prices once I know what they are. I assume I can keep the stock flywheel for any setup (stock, 16g, 18g)