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CTSC: Low boost or high boost? WWPD?

Joined
18 October 2015
Messages
1,202
Location
Cleveland area, OH
I have recently procured a used Whipple CTSC to use on my ‘99 targa. It comes with both low and high boost pullies, 550cc injectors and an AEM V2, which the previous owner was using to run a high boost setup. No CT FIC with the setup.

Plan is to take it to Source 1 for install, since they are reasonably close to me.

My original plan in seeking a CTSC was to run low boost for max reliability. However, I now have the option and equipment to run high boost if I wanted. I’d have to tune anyway even to run the low boost pulley.

I don’t plan to buy new headers given minimal gains from changing my NA2 headers. I have a Pride lightweight exhaust, so free flowing already. I don’t plan to track the car more than 1-2 times a year (NSXPO and another HPDE I do regularly), so I don’t plan on an intercooler yet. SC was rebuilt in the recent past, so not planning to do that for now.

So given this, What Would Prime Do? Low or high? How reliable is the Whipple CTSC at high boost and a conservative street tune? That will decide for me more than anything else. Been reading lots about it and having a tough time deciding. And no, I don’t want to go turbo, LOL.
 
My car came with the standard low-boost setup. It had 37k miles when I got it. When, four months later, it pulled a couple head bolts out of the block, I changed the fueling to an FIC and larger injectors. At that same time, I bought a “high boost” pulley from Shad. What you will find is that there are many different pulley sizes and the boost generated by each depends on your engine displacement (obviously) but also seemingly some other factors of your setup.

Anyway, I decided not to use the HB pulley, because the $11k rebuild scared me; it also scarred me. ;) I based my decision on the high degree of unknowns regarding primarily intake-air temperatures. I also added a water/water-meth spray system, but with a nozzle before the blower (a very inefficient place for it). I also added Zeitronix sensors to monitor IAT.

Temps are an issue. They are generally fine and spray-cooling works but it is better in certain situations than others. It seems to benefit from sustained on-throttle periods, which autocross lacks to a large degree. Street driving is kind of the same. I think my results would be better with post-blower spraying, as advocated by Regan, [MENTION=20915]RYU[/MENTION].

So I’m currently happy I didn’t use the HB pulley. If I had a better charge-air cooling strategy, I might feel differently. Without any cooling strategy, I’d definitely want the LB pulley. For reference, my boost pressure is generally ~7 psi. And my car made 399 whp, in quite cold ambient conditions, on a dynapack hub dyno. You should also think about the ambient temperatures in which you drive your car. It will strongly prefer cool weather with the SC.

-jason
 
This question comes up about every month so. A while back I posted a youtube video to help answer questions. This is just my viewpoint/opinion/findings. YMMV

https://youtu.be/pey4tGDZ8gc

If you have any questions after watching this.. just ask.

FWIW - I don't think going high boost is worth it. With Superchargers spinning the shafts faster introduces diminishing returns in several ways.

(Hi Jason!)
 
Thank you, gentlemen! That tells me not to deviate from my original plan of low boost. I’m interested in exactly what type of high boost pulley I have; I’ll post a pic when I receive the kit. It’ll be useful for future reference. I’ll likely still use the larger injectors. I still have no choice but to get a tune. At least I can reprogram for 91 if I can make it to NSXPO this fall. (We use 93 in the East.)
 
If you do end up going with an aftercooler, I know everyone will tell you the DA core is too small. But, it’s 90 degrees here where I live daily and my IAT’s have yet to exceed 108 degrees. Even after 1 hour driving under boost. It’s worth it in the long run if you can afford it... As for longevity of high boost, I cannot comment yet. But don’t get it twisted. There are plenty of low boosted ctsc’d motors that blow. Like mine. People just don’t document them. In 5 months, you’ll get used to low boost power and want more.
 
Loved the video [emoji106]especially all the details shown with your NSX on the lift. It is packed with great info and your car just gets more awesome!

FWIW my OS Giken diff has had Motul 75/140 for a while which works for me, living with a little noise in parking lots and sharp turns from a stop. I know I could have it quieter going heavier on the fluid but this is my sweet spot preserving my synchros. I am curious what your special sauce you come up with so please keep posting here.

Last thing in the Farah review where he says the other white NSX rode smoother, were you on 9k/9k springs? (This is from memory but I can post the timestamp.) Anyway I am on Swift 9k/7k on KWV3 and I like how that works for me on PSC2 tires and admittedly some wannabe racecar delusions. The suspension stuff will always be intriguing especially when you can learn from others experience.

Thanks again for the terrific video.!
 
My personal experience with the CTSC low boost is that it's totally useless if you track the car.
I would loose 3 sec per lap between the first and the 10th lap due to heat soak.
A normally aspirated NSX was just as fast as my car at that point in time.
Since then I moved to a LoveFab turbo setup; another world alltogether but...no cats!
 
Loved the video [emoji106]especially all the details shown with your NSX on the lift. It is packed with great info and your car just gets more awesome!

FWIW my OS Giken diff has had Motul 75/140 for a while which works for me, living with a little noise in parking lots and sharp turns from a stop. I know I could have it quieter going heavier on the fluid but this is my sweet spot preserving my synchros. I am curious what your special sauce you come up with so please keep posting here.

Last thing in the Farah review where he says the other white NSX rode smoother, were you on 9k/9k springs? (This is from memory but I can post the timestamp.) Anyway I am on Swift 9k/7k on KWV3 and I like how that works for me on PSC2 tires and admittedly some wannabe racecar delusions. The suspension stuff will always be intriguing especially when you can learn from others experience.

Thanks again for the terrific video.!

Thanks for the kind words [MENTION=30599]prym8[/MENTION]. I'm embracing this YouTube new media thing but not sure how some of these YouTube guys do it...it takes so much more time than typing on a forum. I'll respond on my thread and tag you so I don't muck up this one ��

Basically, Matt tested my NSX in it's most track oriented configuration... That was the premise as to provide the biggest contrast with Kuni's NSX on video.
 
[MENTION=30599]prym8[/MENTION] also lmk pls how many miles you have on the Motul. I just ordered 3 bottles of

Redline Oil GL-5 75W110 Gear Lube

Btw... OS Giken has ignored me completely. They went from very helpful to zero in no time. Sigh...
 
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I have used it for about 6k miles.. only 3 track days but lots of twisties.

Any chance you'd be able to compare (like at nsxpo or a track day) with a someone's diff that's been WPC treated?
 
[MENTION=20915]RYU[/MENTION] , I finally watched your video. Was on a cruise when you posted in this thread, and satellite internet on the ship was too slow...

Any case, what an excellent job explaining some of the logic behind cooling the CTSC. I now have some tools to use in deciding how to proceed. I will keep the thread posted.
 
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