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Standing at the cliff, wondering whether to:
A) Just step away...step away
B) Other options I won't get into here so as not to derail this thread
C) Get the $15k bolt on / install / tune kit at Protosport to take my 95 993 NA twin plug 3.6 and put on the intercooler and such.
Update: D) would be some sort of a Stage 2, where the internals are upgraded as well. I need to get a build list of what that is, by after reading posts and talking to mechanics and listening to my gut the (C) choice Stage 1 isn't really an option for me.
Note: Car is true dual use...I go to the Hamptons, Boston, DC, Target, whatever, and also The Glen, NJMP, etc. Red DE, not racing, but I don't want to take away the bullet proof nature of the car.
So, anyone have good/bad/pretty/ugly experiences?
My basic concern is of course that the rest of the car is not made for 400 hp, and what would I be doing to it? So far I'm looking at the externals only, bolt on package.
I'm in the same boat just with my 964. Interested to hear people's opinions and experiences.
By the way, is there a link to this setup? I've looked for info but he bent seen anything other than threads mentioning it. TPS supercharger seems to offer similar hp results but again, no really solid info on it.
I've just been emailing Protosport. There is a kit, then you can go big with tearing down the engine, bigger turbos, etc. $$$$$$$$$ of course the more you go.
We put a Protomotive twin GT28 kit in my fathers 993 C4 along with a fresh full rebuild of the motor to stock spec (high compression.) It took a little tweaking, but 3 or 4 years later (can't remember) and 15k miles under it's belt, it's been flawlessly reliable and is absolutely one of the most fun cars I've ever driven. But... he does not track it. I have a 964 DE car and I wouldn't even consider adding boost there.
Little more info on the build:
Varioram engine with a non VR intercooler (larger, required trimming the wing)
Stock compression on Mahle P&Cs
7lbs of boost
325whp on a Mustang Dyno at sea level in 72F temps
Like I said, it's been dead reliable. Had a MAF fail, but that wasn't the turbos fault. Other than that, it has always ran great on the original Protomotive tune. But tracks add a LOT more stress to a system that would already be under a lot of it. If the motor isn't built to suit that kind of abuse, I would resist the temptation.
Next time you are at NJMP, feel free to reach out. I would be happy to give you a ride around town in the car. I live about 25 minutes from the track. EDIT: Just noticed you are a PCA instructor, you can drive it yourself
Running stock compression ratios with boost can be very risky.The physics get tricky. There are very good reasons why factory turbos use lower compression-easier to control. Mostly safe for street use but take it to WGI and the back straight might well be deadly.
I consider my turbo conversion to be an improvement over the factory setup. Equal length headers, large port/valve heads, RS type cams, GT2860's, twin plug, VRAM etc.
I opted to stay high compression for a few reasons. One it keeps the bottom end perky when running larger cams. Think corrected compression ratio not static. Same is true when you add boost. Intake valve closing, static compression and boost all combine to determining final corrected compression ratio. I also intend to run E85 eventually so the high compression/boost is ideal for that fuel.
My setup has been run on the track 6 times. Some of the local 993tt guys can vouch for its performance. It's faster than Greg's UMW stage 3 993tt.
No worries about the rest of the drivetrain. Once you address the clutch it's up to the task. Protomotive has been doing conversions like these for years.
400 crank hp on pump gas is doable on 93 oct. Using 91 oct I would back it off some. With built motor and E85 you can get near the 700hp mark.
Running stock compression ratios with boost can be very risky.The physics get tricky. There are very good reasons why factory turbos use lower compression-easier to control. Mostly safe for street use but take it to WGI and the back straight might well be deadly.
Don't let this happen to you.
"Whaddaya think", a little heat involved there? :-0
What's the delta on dollars spent to convert versus buying a TT? These numbers plus a lot of uncertainly and " while you're on there" options may argue for a swap. There's a great 993tt listed for around $ 130- if had for say, 120- less the sales of a NA non wide body for $ 40-45k , less turbo conversion, new clutch, lwf, and possibly other - you have a difference of 40k- maybe less.
To get a wide body TT with better brakes, full leather and sport seats ( like the one listed on RL) the difference is minimal and the motor is built correctly with all titanium connecting rods, lower compression,etc.
I'd be buying the 993tt- not to mention the resale value issues
My .02- let's the debate begin.....
Even when comparing apples to apples the build vs buy always favors the latter assuming it's built the way you want.
I have been around the factory turbos since they were new. Early on guys would mod them to taste. Stock they are a bit of a yawn.
I agree the OP should look at buy options before moving forward with the build. If faced with a similar decision I would ask myself what I want to do with the car. Buying a stock 65k mile turbo then modding/tracking/driving it to 80k+ miles will kill any value. I think well built higher miles modded turbos are currently under valued. Given a 100k-120k budget I could find a GREAT modded 993 turbo.
Back to moddding the original 993 power plant conversation. The heads and cylinders share the same unique alloy as the turbo but have bigger valves, ports and twin plugs. Both share identical blocks. The turbo does have stronger rods but even those are know to be a weak point and are the first things replaced when building a TT motor. Lower compression pistons would be a good option for most. I have good reasons for keeping the high compression ones. Notice the OEM trend to do the same?
Not sure what car the OP has but starting with a C4S gets you pretty much the same brakes/drivetrain.
Turbo conversions should not be overlooked. I've seen a few that were well done. I've also seen some nightmares!
Sunday I spent 80 miles driving around the back roads through west Marin and Sonoma. It again reminded me why I love the combination (vram turbo conversion) so much. Sure WOT is a hoot but what really sets the car apart from it's factory counterpart is the responsiveness of the motor. Slight tip in and the motor just leaps into action. No lag just seamless power delivery. It feels more like a big V8 than a turbo charged car.
Best of luck with your decision. If you were only closer I could give you an idea of what to expect. On the flip side see "the other eric" protomotive thread about his experience. Not so good. Some of that can be chalked up to DIY mistakes. Non the less it was an expensive fruitless venture. Lastly consider fuel availability options. I would not attempt this on anything less than 93 oct. Best to go even higher and blend in race gas. Better yet E85.
Well, I do think you went bigger than most on the build, no? It wasn't just the 15k bolt on / tune, IIRC.
Would there be much of a difference with non-vario 95?
I did go bigger by building the motor. Prior to that it was a stock block with prototech turbo kit. While the performance did get better post build the epic personality was there before with the stock block. Felt like a big NA motor. No lag!
I think the VRAM is a big part of the magic. It really broadens out the power curve. Even more so with boost. The VRAM also comes bigger valves and ports. Without having VVT the VRAM is the next best thing.
If I had a 95 I would still turbo it. I would do somethings different with the IC though. You'd give up some of that flat power curve. I would also suggest some wide LSA cams to help flatten out the power curve and bleed off some compression for best results.
I am biased I am friends with Paul and John as well as a long time customer.
John is meticulous about his work. I have friends that have had various degrees of engines converted by them all of which have had extensive track time and they are pretty bullet proof. I have seen low boost turbos on 993 engines lasting for years of track driving 30k miles and still running.
I almost purchased one of their stage 1 964 C4 widebody a few years back and the car drove like a N/A car all the power is up high with no signs of turbo lag. I also have a 964 I built for the track. It is using a very high strung 993 varioram engine with low boost twin turbo setup. This is not for street use so it runs like crap under normal driving conditions but on track it is a monster. No lag but is not happy under partial throttle low rpms. Once on the gas the car just pushes you forward with a vengeance. Still trying to learn how to control the power. It seems to have three power levels basic 60% throttle which is quick, 75% which is fast and 100% which is ludicrous. I can pull on 991 GT3's on the track in the straights. My problem is just getting used to putting the pedal down earlier and not over braking since it has me moving far faster than I am used to entering turns.
I don't think you will have any issues. John will make sure the parameters are in check and set you up with a car that will be a blast to drive and tuned to the safe side.
As far as the cylinder pictured I have seen that occur on N/A 993 engines when the owner drove the car hard with too little gas in the tank which leaned out the mixture and caused the failure. When done correctly this should not be a concern.
If your concerned about the shop don't be. If your concerned about turbo charging a 993 engine with low boost I wouldn't be. Just talk over the details prior to begining the build.
Some further food for though. This comparing a factory 993 turbo @ 14psi with 8:1 low compression to 993 VRAM @ 7psi with a 10:6CR (true CR not advertised) high compression & DC21 cam. The longer duration cam with later closing intake helps bleed off static compression and moves the power curve up.
Things are a bit more complicated than this when you factor in VE but you get the idea of why the high compression low boost setup works.
Factory 993 Turbo
Static compression ratio of 8:1.
Effective stroke is 2.57 inches.
Your dynamic compression ratio is 6.98:1 .
Your dynamic cranking pressure is 133.72 PSI.
Your effective boost compression ratio, reflecting static c.r., cam timing, altitude, and boost of 14.5 PSI is 13.87 :1.
V/P (Volume to Pressure Index) is 77
VRAM
Static compression ratio of 10.6:1.
Effective stroke is 2.50 inches.
Your dynamic compression ratio is 8.97:1 .
Your dynamic cranking pressure is 185.35 PSI.
Your effective boost compression ratio, reflecting static c.r., cam timing, altitude, and boost of 7 PSI is 13.24 :1.
V/P (Volume to Pressure Index) is 103
11-23-2016, 04:07 PM
Experience with Protosport NA Turbo kit?
