To Kraftwerks:

As s2000junky said, we all basically consider your kit as maxed already, straight out of the box because in order to run more boost, you HAVE to lower the engine's redline. Yes, I get that the C38-81 can run more boost, but none of us want to lower our redline. Thats the catch here. We are not going to lower our redlines to run more boost. That's why many people bring up other kits like TTS and even SOS because they both can run more boost than your kit while sustaining the stock redline. Other than that fact, I would have loved to buy your kit.

 

They "KW" have still not answered my questions of why TTS can make 18psi and they can't.

Sent from my SAMSUNG-SGH-I337 using Tapatalk

 

Been following this and other Kraftwerks threads for a while as I’ve had my eye on this kit.

I was wondering if someone could help shed some light on this for me.
I’ll start by saying I do not have an engineering background, I’m a finance guy who likes cars.

So using the C38-81 charger as a base and the max flow from Rotrex
Max flow 0.58kg/s * 1731.8 = 1004cfm (calculation was taken from the Rotrex info page)
We know from Krafwerks that the blower is almost spinning at max speed so let’s use this cfm number.

Now Kraftwerks has told us the charge pipeing is 2.5-3” and using the following info I found on Honda-Tech it seems that the charger at 1000cfm is already passed the max efficiency limit at the 2.5” bottleneck.

(Following info taken from honta-tech FI FAQ)

2.5" piping
4.90625 sq in = 2.453125 x 2
300 cfm = 100 mph = 0.13 mach
400 cfm = 133 mph = 0.17 mach
500 cfm = 166 mph = 0.21 mach
600 cfm = 200 mph = 0.26 mach
700 cfm = 233 mph = 0.30 mach
800 cfm = 266 mph = 0.34 mach
900 cfm = 300 mph = 0.39 mach
913 cfm max = 304 mph = 0.40 mach

2.75" piping
5.9365625 sq in = 2.96828125 x 2
300 cfm = 82 mph = 0.10 mach
400 cfm = 110 mph = 0.14 mach
500 cfm = 137 mph = 0.17 mach
600 cfm = 165 mph = 0.21 mach
700 cfm = 192 mph = 0.25 mach
800 cfm = 220 mph = 0.28 mach
900 cfm = 248 mph = 0.32 mach
1000 cfm = 275 mph = 0.36 mach
1100 cfm max = 303 mph = 0.40 mach

3.0" piping
7.065 sq in = 3.5325 x 2
300 cfm = 69 mph = 0.09 mach
400 cfm = 92 mph = 0.12 mach
500 cfm = 115 mph = 0.15 mach
600 cfm = 138 mph = 0.18 mach
700 cfm = 162 mph = 0.21 mach
800 cfm = 185 mph = 0.24 mach
900 cfm = 208 mph = 0.27 mach
1000 cfm = 231 mph = 0.30 mach
1100 cfm = 254 cfm = 0.33 mach
1200 cfm = 277 mph = 0.36 mach
1300 cfm max= 301 mph = 0.39 mach

The TTS setup uses the same C38-81 blower with larger piping and we know it makes more boost/power.
Would it not be safe to assume, to push more boost/make more power all you have to do is increase charge pipe size to a minimum of 2.75”?

Based on these numbers I’d assume that over 913cfm the 2.5” portions of the pipe cause restriction resulting in air pressure (for lack of a better term) fighting itself to get through.

Again, take this with a grain of salt. I don’t have the technical knowledge to fully understand this but maybe someone here with an engineering background can explain.

 

I remember TTS said they dont warranty the C38-91or 92?

Either way, its a mystery why KW can't max out to 18 like TTS. Does the pipes and intercooler makes that much of a difference? Don't think KW can answer that question. They both are using the same blower. And the only claim of 18 psi is from TTS. Is there anybody in the State with the TTS race can back up that claim? I guess we will soon find out once the TTS kits starts shipping.

 

Who actually has a TTS kit running 18psi, we'd like to see it. If it is local we'd also like to see it.

 

TTS are not claiming it, they have proven it on their dyno.

Sent from my SAMSUNG-SGH-I337 using Tapatalk

 

Charge pipe diameter does make a difference in net boost seen at the manifold. A larger diameter pipe should yield more pressure. Running an Aftercooler vs a FMIC on a supecharger has a huge difference in pressure. The Aftercooler drops a mear .5 of boost average compared to the 3-4psi FMIC counterpart. Apparently the guys running the rotrex blowers choose to incorporate an FMIC, which on any other centrifugal blower (Paxton) yields less boost/less power. The efficiency loss of the fmic cant compensate for any marginal added cooling the fmic provides in some situations. The rotrex blowers do spin nearly twice as fast I understand ( turbo charger levels) so I equate the need to run an fmic to that, but your losing a lot of the added efficiency of moving to a rotrex design as well. Doesn’t really make sense to move to this kit from a power standpoint if that’s the primary goal. The Paxton/novi1200 produces 1150cfm at max blower speed which is a substantial improvement still over the c38 if the 1000cfm is accurate, couple the 1200 with a aftercooler set up and it should yield far greater potential. I dont see the new c38 kit getting much more then about 415whp Dynojet.

 

Well said Sir!

 

@leoxle, we understand what you are saying, it's just interesting because we'd think people wouldn't mind making MORE power, SOONER... not having to rev it as high to make peak power didn't seem to be a big deal, but it's been noted.

You've touched on some valid points that we are concerned people are not understanding. No, to our knowledge nobody has this "18psi Race kit" in the states. We think the real question people should be asking is IF the TTS kit really is making 18psi, not why Kraftwerks isn't offering a 18psi kit. The argument about the intercooler being the determining factor is also something we hope people begin to think about more in-depth, clear intercooler efficiency differences really won't be seen until after about 25 psi, below that the differences are minimal. Has anyone asked what core TTS is using? We've giving our input about the piping and intercooler already, again we tested 2 inch, 2.5 inch and 3 inch on the dyno, seeing no serious gains with the 3 inch piping, thus, Kraftwerks decided to go with a 2.5-3 inch combination.

We've been doing our best to provide facts about our kit. Yes, the missing parts was a "goof", we're working on that and we have no problem making it right if you are missing something, WE WILL GET YOU YOUR PARTS. But you are correct, TTS stated no warranty, possibly because they know you will be over-spinning the charger to get to the claimed 18psi mark. At the end of the day we know the Kraftwerks kit provides great power, and we're not risking charger failure.

 

http://m.youtube.com/watch?v=o5Gkar6R5Pk

http://m.youtube.com/watch?v=Xt492vZFyZs