Planet-9 Porsche Forum banner

1 - 14 of 14 Posts

·
Cayman The Destroyer!
Joined
·
2,632 Posts
Discussion Starter #1
I'm converting my single turbo 4.0L that made 573 HP at the wheels to a twin turbo setup. The single is an awesome setup but the crossover exhaust pipe won't allow the under body diffuser to fit correctly. The new set up won't make more peak HP but it will have a much fatter torque curve and less lag due to the segregation of the exhaust pulses and the much lower inertia of the smaller wheels. It's been an interesting project to engineer as we couldn't find state of the art off the shelf turbo's that would do the job and a custom turbine and compressor set up was needed. One other interesting bit is this will be a air-air intercooled Cayman. Probably the first ever.
 

·
Registered
Joined
·
51 Posts
How do you keep the tires on the ground with even the single turbo. With 573hp, it must be hard to keep traction. :hilarious:

It sounds like an interesting project (and fun)....
 

·
Cayman The Destroyer!
Joined
·
2,632 Posts
Discussion Starter #3
On the street I always kept it in low boost @ only 480 WHP. It would still spin the 295's in second gear from a roll. The car is now track only and rides on very sticky slicks mostly in 3rd gear or higher.
 

·
Premium Member
Joined
·
6,776 Posts
DiverDog, you keep raising the bar!

I wonder who'd do the software tuning for such venture. And how much all of this did eat out of your wallet so far.

Looking forward for some videos when it's put back together.
 

·
Cayman The Destroyer!
Joined
·
2,632 Posts
Discussion Starter #6
The single turbo is a Garrett GTX. I have to look up the exact model. Hassaan, actually the conversion to twin turbo is not too dear because the engine is ready for it and the AEM brain we are using for the track car is already in place. The two turbos ~ $3,500 + wastegates ~$800. I don't know how much the fab will be but not much more than the changes for the air-air intercooler for the single. Programming for the AEM DME is much easier than the Porsche DME, no encryption and hidden maps to deal with. I'm sure it won't be cheap but much much less than the first go around.
 

·
Premium Member
Joined
·
6,776 Posts
I understand the passion for mods and hp. And I see you dedicated the car for the track.

May I ask why why not go for a GT4? Or a GT3 instead since you're track focused with your toy?
 

·
Cayman The Destroyer!
Joined
·
2,632 Posts
Discussion Starter #8
I lost my desire for a mega street car and so many of the changes I made to my CS where directly applicable to the track I decided to convert it. I like the mid engine platform and I'll be competing directly against GT3's. My next street car will be something way more conservative perhaps a Audi S5 or even a stock Boxter to go along with my trailer tow vehicle a Ford F150 pickup. I drove an S5 today and liked it quite a bit but my 11 year old Infinity G35 still looks and runs well so I'm in no hurry to buy.

BTW I love your new ride!
 

·
Registered
Joined
·
27 Posts
just for the records, here link to my cayman s twin turbo build done in 2013/2014, 3.4 liter though

The Italian job - Cayman GT2 - Porsche Cayman 987 Forum / Kaufberatung von PFF.de

I did use K16/K24 turbos. My intercooler is watercooled, but there is also an air inlet from the side window that blows directly to the intercooler. You have to cool the engine bay as much as possible otherwise temperatures go up and the dme will reduce power for engine protection. I did my own programming on the dme.

Andreas

P.S. For easy measurement of the engine power I do use a simple android phone app, Home - PerfExpert

For the cost of 15 USD you can do your own measurements on the street, and it is pretty precise also.
 

·
Registered
Joined
·
1,587 Posts
It is too bad you are not taking it out on the street. The look on some faces in "superior" cars when you open up that Cayman is worth the price of admission!
 

·
Cayman The Destroyer!
Joined
·
2,632 Posts
Discussion Starter #11
It is too bad you are not taking it out on the street. The look on some faces in "superior" cars when you open up that Cayman is worth the price of admission!
I've always enjoyed having a "sleeper" to drive on the street. My fist one was a 1966 Sunbeam Tiger with a built 289. 2600 lbs and ~325 hp. Back in the day it was a really hot car. I liked driving the turbo CS on the street but I'm actually a very conservative driver now and I rarely used a fraction of the power. Using all that power in 1st & 2nd would require drag slicks. Acceleration in 3rd- 4th gear was f'ing amazing but a sure way to end up in jail.

These days I prefer to test the car and myself on track. I haven't owned a convertible since the Tiger and I think a 981 Boxter is calling to me.
 

·
Registered
Joined
·
65 Posts
Did you look into the Aerochargers? They are a variable vane and twins should be easy. One big advantage is they are self oiled. What are you doing with your single? My car is going out to Vision next week and will get a built 3.8. Would be interested in your single. Lastly in regards to the AEM, I would consider the newer AEM Infinity. I have it on my turbo NSX (600 RWHP) and it is beter than my prior AEM Series 2.
 

·
Cayman The Destroyer!
Joined
·
2,632 Posts
Discussion Starter #13
Did you look into the Aerochargers? They are a variable vane and twins should be easy. One big advantage is they are self oiled. What are you doing with your single? My car is going out to Vision next week and will get a built 3.8. Would be interested in your single. Lastly in regards to the AEM, I would consider the newer AEM Infinity. I have it on my turbo NSX (600 RWHP) and it is beter than my prior AEM Series 2.
The variable vanes are interesting but we will need to do waste gating as well because we will have to roll boost off up top to stay within class HP rules. Making the systems work together would be a big challenge. Since the engine will be working in the 4,500- 7,000 RPM range I don't think the variable vanes will make much of a difference anyway. Yes we are using the Infinity. I'll be selling the turbo and TPC intercooler. I also have a Porsche DME software tune that would work well with a 3.8L (same stroke as my 4.0L)
 

·
Registered
Joined
·
65 Posts
The variable vanes are interesting but we will need to do waste gating as well because we will have to roll boost off up top to stay within class HP rules. Making the systems work together would be a big challenge. Since the engine will be working in the 4,500- 7,000 RPM range I don't think the variable vanes will make much of a difference anyway. Yes we are using the Infinity. I'll be selling the turbo and TPC intercooler. I also have a Porsche DME software tune that would work well with a 3.8L (same stroke as my 4.0L)
The Aerochargers have an internal wastegate which is easy to manage. Since the spool so quickly, you will reach peak boost way before 7K. Because of the variable vanes, they are extremely linear in power delivery as compared to the typical turbo which can give you huge kick in the pants even when running at high RPM. I also have the GT35 in my NSX and when I am at the track, had real issues with too much HP/torque when boost kicked in so I have turned down the boost as I could break the rear end loose at 90 in 3rd gear on the straights (3.5 L Comptech race engine). On the NSXPRIME forums, there is a guy Dave Dozier who has had multiple iterations of turbo and SC, currently has twin aerochargers with ALOT of track time, I would contact him if you are interested.

Shoot me a PM about your turbo setup. Very interested. By the way, T3 or T4 setup. I plan on using a Comp turbo 6062? with a T3 housing since it is also a self contained design and doesn't require oiling, just water cooling. Done with scavenge pumps.
 
1 - 14 of 14 Posts
Top