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Turbo / SC Nightmares anyone?
- Thread starter captainjman
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^^ Cost can be a very powerful driver. Used CTSC's have sold for ~6k. If I wasn't set on a twin screw i'd probably pay ~1/2 for a centrifugal SC just to have fun with.
However...! At the end of the day Daddy wants a 3.8L
However...! At the end of the day Daddy wants a 3.8L
^^ Cost can be a very powerful driver. Used CTSC's have sold for ~6k. If I wasn't set on a twin screw i'd probably pay ~1/2 for a centrifugal SC just to have fun with.
However...! At the end of the day Daddy wants a 3.8L
A 3.8 sounds great, but it makes me wonder about reliability. I mean, there are 1000's of CTSC out there and few few problems. How many 3.8's are there?
That's an entirely different conversation :wink:
I am going to say that it's because it's cost prohibitive not because people are blowing motors.
If it cost me same on a $/hp for the 3.8 over the CTSC I'd do it in a heart beat. However it's seems to be at least twice as expensive...that aint chump change.
To add to the previous post:
http://www.nsxprime.com/forums/showthread.php?t=108710&highlight=stroker
Not that many but it's a start and I am sure there are plenty that haven't posted about their cars.
http://www.nsxprime.com/forums/showthread.php?t=108710&highlight=stroker
Not that many but it's a start and I am sure there are plenty that haven't posted about their cars.
I don't get the fascination with "NA" or ITB's. Other than it sounds cool, and ITB's look neat and are loud... they both have a whole host of drawbacks. I think the fascination is based more on their exotic nature than real fact. Why would I want to tear apart a perfectly good motor and stroke it when a CTSC gives me the same sort of power curve along with the same level of horsepower and is a bolt-on? I mean why would someone go through all the trouble of essentially building a new engine when a reversible bolt-on does the same thing for you more or less. And then to spend double on it... and then add ITB's for an extra 5K (and these aren't exactly hassle free either). You'd really have to have a few screws loose.
I don't get it... you buy a CTSC, you bolt it on, nothing to tune, you pass emissions, retain your favorite exhaust note, you gain 100 HP... you don't like it you take it off and you get most of your money back. Your engine is still NA, and still untouched mechanically.
I find this really surprising coming from you (no offense intended). Aren't you FI now? FI does have it's drawbacks. The grass isn't always greener on that side.
for example, power curve/delivery, throttle response...
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It will rev faster than an S/C motor as you are no longer driving a supercharger and have the associated parasitic loss. I don't think it would remind me of my bike, I'd love ripping through the gears on my CBR, it might not throw me back but it would pull all the way to redline. Nice flat torque curve too, makes it very predictable. Oh yeah it will sound cool too:biggrin:
Anyway like I said $/hp, I would say the CTSC or SOS SC is what I'd consider right now as that seems as close to flat torque curve as you can get with the FI options. I wouldn't mind a ride in some of other NSX's that have some of the latest turbo offerings just out of curiousity though.
I agree with Dave. It makes the most financial sense to me, plus a track record of very good reliability vs being basically a one off engine build.
Just a few quick notes clr1024 to counterpoint - I think we should continue this in another thread as RYU pointed out without crapping this one up if you'd like:
1) You're neglecting that a turbo does not get its energy for free either (like you have pointed out with a belt-driven supercharger). A turbos losses come in the form of pumping losses from increased backpressure on the exhaust side (your engine is a giant air pump). Please don't say backpressure is good....:wink:
2) The only downside of the driveshaft from the Basch is minute loss due to rotational inertia that causes. The ball bearings (or maybe it uses needle bearings - don't know) supporting it have very little frictional losses in the grand scheme of things. I would prefer the minor frictional losses and added moment of inertia on the supercharger response as opposed to having a larger charge pipe (I see your comment on that has been corrected).
3) Some people still prefer a centrifugals pump curve (turbo OR supercharger) as opposed to the positive displacement pump characteristics (me being one of them). I don't care about roasting tires at a stoplight, or how much torque I'm making at 3000RPM. How much time I spend in that RPM range is miniscule when I'm "on it." Power should be concentrated in the 5000-8000RPM range. That's how real race cars operate, and the way Honda intended Of course, everyone's likes/dislikes are different - that's why we have options.
Just trying to help educate on why, once again, there is no perfect technology.
Dave
1) You're neglecting that a turbo does not get its energy for free either (like you have pointed out with a belt-driven supercharger). A turbos losses come in the form of pumping losses from increased backpressure on the exhaust side (your engine is a giant air pump). Please don't say backpressure is good....:wink:
2) The only downside of the driveshaft from the Basch is minute loss due to rotational inertia that causes. The ball bearings (or maybe it uses needle bearings - don't know) supporting it have very little frictional losses in the grand scheme of things. I would prefer the minor frictional losses and added moment of inertia on the supercharger response as opposed to having a larger charge pipe (I see your comment on that has been corrected).
3) Some people still prefer a centrifugals pump curve (turbo OR supercharger) as opposed to the positive displacement pump characteristics (me being one of them). I don't care about roasting tires at a stoplight, or how much torque I'm making at 3000RPM. How much time I spend in that RPM range is miniscule when I'm "on it." Power should be concentrated in the 5000-8000RPM range. That's how real race cars operate, and the way Honda intended
Of course, everyone's likes/dislikes are different - that's why we have options. Just trying to help educate on why, once again, there is no perfect technology.
Dave
J3) Some people still prefer a centrifugals pump curve (turbo OR supercharger) as opposed to the positive displacement pump characteristics (me being one of them). I don't care about roasting tires at a stoplight, or how much torque I'm making at 3000RPM. How much time I spend in that RPM range is miniscule when I'm "on it." Power should be concentrated in the 5000-8000RPM range. That's how real race cars operate, and the way Honda intended
That makes sense if you are building a race car, but on the street I would venture to say most people spend A LOT more time at 3,000RPM than 8000.
The only Turbo/SC nightmares Ive seen come poor tuning, using a non-reputable shop or just flat out taking shortcuts. There are choices now to get basically whatever you want power wise in the nsx, and most being reliable. I'm not sure which exactly system i'd want in my car but, I DO know that when its time to go down that road I gotta have a good shop and the funds to make the nightmares less of a nightmare. Good thread BTW.
Just a few quick notes clr1024 to counterpoint - I think we should continue this in another thread as RYU pointed out without crapping this one up if you'd like:
Don't worry I know back pressure is not good, no matter what kind of system you run. No turbo energy isn't free...but it's a lot cheaper:wink:
I would worry about parts breaking due to torsion of the long thin drive bar to the S/C, I would also worry about things flexing vs something bolted to a more solid flange/coupling.
3) Some people still prefer a centrifugals pump curve (turbo OR supercharger) as opposed to the positive displacement pump characteristics (me being one of them). I don't care about roasting tires at a stoplight, or how much torque I'm making at 3000RPM. How much time I spend in that RPM range is miniscule when I'm "on it." Power should be concentrated in the 5000-8000RPM range. That's how real race cars operate, and the way Honda intended
Yes you are correct, in that people have different preferences...as for Honda, I don't think they have built an engine that makes all it's torque up top. Maybe their turbo applications on F1 cars. Remember VTEC was created to let an NA car breathe better at high RPM, not an issue with FI cars since you are pushing the air in.
Anyway you are right, I do not want to hi-jack the OP's thread, so I won't write anymore about FI this or that or FI vs NA.
+1 and that throttle response down low not just off the the line is exhilarating, right Dave?
Posted for reference:
AP-X turbo 5.5psi hits its max torque of 298 at 5.5krpm, then dribbles down as the rpm's rise ending around 250 torque.
CTSC NSX Low boost 5-6psi? Hits its max torque of 243 at 5krpm but the torque curve is very consistent and linear like others have said which makes it much easier to control.
Boostzilla Centrifugal SC 6.6psi hits its max torque at 7krpm, so it utilizes the entire rpm band constantly building up the power.
To me the centrifugal SC is not the worst of both worlds, but the best. Up to -100F lower intakes temps compared to a CTSC. No need to run a oil scavenge pump (just one more headache that could fail). You could still swap your stock exhaust and cats on and possibly pass the sniffer. (Can't do that turbo). The dyno looks very similar to the turbo dyno aside from the big difference of the turbo hitting its max torque so fast and most likely creating lots of rear wheel spin.
AP-X turbo 5.5psi hits its max torque of 298 at 5.5krpm, then dribbles down as the rpm's rise ending around 250 torque.
CTSC NSX Low boost 5-6psi? Hits its max torque of 243 at 5krpm but the torque curve is very consistent and linear like others have said which makes it much easier to control.
Boostzilla Centrifugal SC 6.6psi hits its max torque at 7krpm, so it utilizes the entire rpm band constantly building up the power.
To me the centrifugal SC is not the worst of both worlds, but the best. Up to -100F lower intakes temps compared to a CTSC. No need to run a oil scavenge pump (just one more headache that could fail). You could still swap your stock exhaust and cats on and possibly pass the sniffer. (Can't do that turbo). The dyno looks very similar to the turbo dyno aside from the big difference of the turbo hitting its max torque so fast and most likely creating lots of rear wheel spin.
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Rev faster when? in neutral? Because once you are driving in gear how fast the engine revs depends on your gearing, weight, and power. Not on anything else. The "parasitic loss" of the supercharger is not the same under full boost as it is when there is no boost. Lets be clear, the supercharger is not always creating the same drag on the motor. It is under load that boost is built and more loss is created.
My engine revs as fast as stock when not under load. If I rev match at shifts, its fast... The car is in neutral and there is no load. So I am not sure what it is you are saying. If the SC had all this parasitic drag all the time not allowing the engine to rev then a lightweight flywheel would do nothing for a CTSC car, but it works just as well as an NA car.
So if this argument isn't there, what is the real benefit of a 3.8 NA over a CTSC motor? I understand sound, possibly a bit more torque. But the power isn't any greater... Like I said there is a real fascination with NA builds but I just don't get it. I can see how it is better if it is a FI stroked motor... but NA stroked motor? Seems like a lot of work for not all that much gain. The argument is there a lot that the car maintains "balance" and "factory like" power band, but look at that CTSC graph above. It is the same as NA. That torque curve is flat as a pancake.
And one more thing.... running on the track, I shift MUCH LESS than I ever did NA, or other NSX's do around me, because I do have torque at 4K. It matters a lot. Just because you can be at 6-8 on a track all the time doesn't mean you want to be. It's from a lack of choice. I am certain with some turbo kits that have even more torque the advantage is huge. I'd be down and upshifting twice as much on some tracks if my car was stock. In short what I am saying is that I am not buying this argument that "you are at 6-8K anyway" and therefore it is OK for your car to produce power in that band. The wider the power band the better. I really don't like this super high RPM only power. It sucks to be honest.
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Ok, I'll make this simple, regardless of which FI system you choose and assuming nothing goes wrong:
<$20,000 : 400-450 whp
<$40,000 : 500 whp
<$60,000 : 550 - 650 whp
Done. :smile:
<$20,000 : 400-450 whp
<$40,000 : 500 whp
<$60,000 : 550 - 650 whp
Done. :smile:
Added basic Supercharger without motor work, included install.
I know about the first two lines... Yea. I think this is correct.
The CTSC on the group buy a few years ago was around $8k. I think some paid $7500. I paid $8500 for the targa kit. Install is around $1500. That's 10K for an installed CTSC targa and 9K for the coupe. I know it's more now, but maybe discounts can be found...
40K and 60K? Those numbers are crazy. Now you are really getting yourself into used Gallardo pricing. I'd still rather have my NSX but I am not sure I'd drop that kind of dough on the engine alone just so I can lose an extra 5K over stock come resale time.
I think Gerard here had over 75,000 miles on his CTSC motor mainly on the racetrack. There are a few more. Some really high mileage CTSC cars. An even power band, lower boost, and lower overall output is also a bit easier on the internals.
40K and 60K? Those numbers are crazy. Now you are really getting yourself into used Gallardo pricing. I'd still rather have my NSX but I am not sure I'd drop that kind of dough on the engine alone just so I can lose an extra 5K over stock come resale time.
I think Gerard here had over 75,000 miles on his CTSC motor mainly on the racetrack. There are a few more. Some really high mileage CTSC cars. An even power band, lower boost, and lower overall output is also a bit easier on the internals.
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