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415HP 1991 NSX...
- Thread starter Zuerst
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And this one puts out 550!
http://www.autospeed.com/A_0035/page1.html?src=twr
http://www.autospeed.com/A_0035/page1.html?src=twr
A Bell twin turb kit at around the cost of GruppM and CT puts out 415HP/420lb vs GruppM and CT at only around 330HP, why didn't more people go turbo?
From the photo, it looks like that car also has a Haltech controller ($1300). And, those numbers are pretty high for the Bell TT kit. Most make about 370 hp at the wheels on 6 psi of boost.
I think its probably because of THE horror story and lack of advertising.
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1994 Red/Black NSX #418
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1994 Red/Black NSX #418
The Bell Twin Turbo is rated at 390hp - I have it in my NSX. I works great and Ive had no trouble since it was installed (over 5 years ago).
That's still higher then CT, GruppM, and the Basch... and if the torque number was correct as he stated, that's a much higher then any of those superchargers...
Just talked to "JIM" that's the guy at mechtech who's selling the car. He says that the HP#'s are estimated at the crank.
He said it Dynoed around 320 to the wheels. the Haltech is part of Corky's kit. He hired Mech-tech to do the work for fuel and timing. The Haltech (F-5) Which is just an additional injector controller that sprays the needed extra fuel into the throttle body (If you look at the picture close enough, you can see the extra injectors.) So that's not on top of the kit, it is PART of Corky's kit. So stay real out there. So much is just perception.
[This message has been edited by nsxlr8 (edited 06 May 2002).]
He said it Dynoed around 320 to the wheels. the Haltech is part of Corky's kit. He hired Mech-tech to do the work for fuel and timing. The Haltech (F-5) Which is just an additional injector controller that sprays the needed extra fuel into the throttle body (If you look at the picture close enough, you can see the extra injectors.) So that's not on top of the kit, it is PART of Corky's kit. So stay real out there. So much is just perception.
[This message has been edited by nsxlr8 (edited 06 May 2002).]
320 WHP equals 415 BHP? Is it legal to advertise such claims?
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91 Red/Ivory #2061
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91 Red/Ivory #2061
See this kind of advertising everywhere.
hate it, but it's there. All the time.
And oh yeah, only the FRONT calipers are upgraded, the rears are just upgraded Rotors
hate it, but it's there. All the time.
And oh yeah, only the FRONT calipers are upgraded, the rears are just upgraded Rotors
My bad. Jim told me he has done several NSXs using the Haltech programmable system, so I thought he would have done it with this one.
You are mistaken on a couple points. Corky does not supply the Haltech with his kit but is happy to delete the Link brand unit from his kit if you prefer to use something else. (Unless he very recently changed the kit.) The work that Mech-Tech did for Corky was only a timing mod to the ECU and in fact the guy who does the simple re-program has since left Mech-Tech. They will (if you are patient) send your ECU to him for the mod, then he sends it back to them and they to you. I’d contemplate a better solution for timing since theirs is very basic anyway.
As for the power, I’m surprised that Jim would quote 320 at the wheels. The numbers in that add are high, especially the torque, but 320 is very low if it really runs 6.5 psi. You should be able to get that at 4 psi easily and more like 370 - 380 at 6.5, more if you have the right fuel system and don’t need to retard the timing so much..
Why not more turbos? SC is so much simpler as an add-on. Turbos are tricky because boost isn’t tied to RPM. That makes accurate mapping of the fuel very difficult (impossible really) without an advanced system tracking more than just boost and RPM. Such systems are available, but expensive and complex.
Of course, the very same thing that makes them difficult also makes them fast. A good turbo will give you both the low end like a CT/SC and the top end like the BBSC. It will also storm up hills like neither of those can because the added load means more boost sooner. The key of course is the area under the curve. For a wide powerband that’s a blast in daily street driving and also kicks but in the 5-8K range at the track, nothing beats a proper turbo.
But, there are still no really good turn-key systems so I can’t recommend it to most people. If you don’t get it right you will either detonate an engine or run too rich and wear out rings and cylinders.
[This message has been edited by sjs (edited 06 May 2002).]
Have to disagree with you on that point. While fully programmable systems are better, many piggy-back units are more than up to the task of handling turbo fuel maps. Just look at the Supra mods - 95% of them are making crazy power with just a piggy backed Rebic/AFC/other injector controller. The aftermaket gadgets to control fuel and timing are really pretty neat. Marc and I talked at length about the best way to manage his engine when he bought my Bell TT kit and the Rebic seems to be doing a fine job on his car. Good enough to run twelve flat on street tires, anyway.
David, you are certainly voice of experience in this area on the NSX, but I still say that a turbo is much tougher to tune for than an SC, and the experts who do this stuff for a living concur.
The problem with the Rebic IV and other "less advanced" piggy-back or auxiliary controllers is that they only see RPM and boost. So, you can do a fine job of tuning it on a dyno where the relationship between RPM and boost are reasonably constant, no problem. From there you can also do on-the-fly tweaking to make it work well enough at the strip where major factors are relatively constant from run to run. (WOT, shift points, level ground)
But now you get it out on the street or at a road course and things can be very different. A given boost level can be achieved at different RPM depending on factors such as throttle position and grade. The limited mapping options of the Rebic make it difficult if not impossible to get the right mixture across the range of real world conditions. You have just the two curves, one for boost and one for RPM. You can set the trigger level and slope, plus an intermediate point where the slope changes. The sum of the two slopes defines your map. Without at least one more element, such as throttle position or CFM, there is little hope of producing a map that is "right" for multiple conditions.
Sure, there are Supras, RX7s etc. making big HP this way, and set up specifically for the strip they work great. But if you monitored the O2 in exhaust accurately during various driving conditions I'll bet they spend much of their time either too rich or too lean. The little Aerodynes make the Bell kit even more sensitive because you can hit max boost even at light throttle and modest RPM on an incline. Great fun, but tougher to tune for than a simple dyno pull.
I’m not saying you can’t get them to work reasonably well, just that they can’t be tuned to the degree of accuracy I’d like, and their limits make me a bit nervous.
The problem with the Rebic IV and other "less advanced" piggy-back or auxiliary controllers is that they only see RPM and boost. So, you can do a fine job of tuning it on a dyno where the relationship between RPM and boost are reasonably constant, no problem. From there you can also do on-the-fly tweaking to make it work well enough at the strip where major factors are relatively constant from run to run. (WOT, shift points, level ground)
But now you get it out on the street or at a road course and things can be very different. A given boost level can be achieved at different RPM depending on factors such as throttle position and grade. The limited mapping options of the Rebic make it difficult if not impossible to get the right mixture across the range of real world conditions. You have just the two curves, one for boost and one for RPM. You can set the trigger level and slope, plus an intermediate point where the slope changes. The sum of the two slopes defines your map. Without at least one more element, such as throttle position or CFM, there is little hope of producing a map that is "right" for multiple conditions.
Sure, there are Supras, RX7s etc. making big HP this way, and set up specifically for the strip they work great. But if you monitored the O2 in exhaust accurately during various driving conditions I'll bet they spend much of their time either too rich or too lean. The little Aerodynes make the Bell kit even more sensitive because you can hit max boost even at light throttle and modest RPM on an incline. Great fun, but tougher to tune for than a simple dyno pull.
I’m not saying you can’t get them to work reasonably well, just that they can’t be tuned to the degree of accuracy I’d like, and their limits make me a bit nervous.
While I would certainly agree that turbos are a bit harder to tune than superchargers (think 3D map vs 2D, to over simplify), they are pretty easy for any experienced tuner. And, while the Rebic/AFC/etc. are not as good as a fully programmable system, they are certainly as good at dealing with a turbo as a rising rate FMU is with a blower. If you are going to dismiss this form of engine management for a turbo, I don't see how you could then find a primitive solution like the CT system (for example) acceptable. It has the same faults your are pointing out for the piggy-backed turbo systems (rich and lean spots due to the impossibility of matching boost and fuel pressure curves).
Don't get me wrong, I'm very pro turbo overall and would not even consider swapping mine for any SC I've seen or read about. I'm just saying that there is a limit to what any tuner can do given the basic facts. As you say, 2D vs. 3D, and no amount of talent can overcome that. At best you can reach a safe compromise that is also optimized under the conditions most important to you. Mostly I’m frustrated that a really good solution is not available at a reasonable price, and is not too complex to tune. We have a distinct lack of experts around here and although I could probably learn to work the complex systems myself, I just don’t have the time, or rather I have things I’d rather do.
I wish this was a better market for car mods because I would be very tempted to open a dyno & tune shop just so I’d have a place to play.
I wish this was a better market for car mods because I would be very tempted to open a dyno & tune shop just so I’d have a place to play.
This car hasn't sold yet, but I am very close to buying it. I am going to fly out there on Thursday to look at the car. I am going to pay $37K for the car. Any comments would be greatly appreciated.
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I looked at this car on Monday. The car has been hit hard from the front. It was originally a black car. The silver repaint was poorly done. Several if not all interior pieces are cracked or damaged in some way. It is about the farthest thing I can think of from showroom condition(like Jim claimed). This car is not worth buying at any price. Please don't waste your time looking at it. Jim @ Mechtech (he is the one trying to sell it) will tell you anything to get you out there to look at the car. At least that is what he did to my friend. I went out to San Diego with my friend to help him inspect the car. Just about everything that Jim told my friend was a lie. He grossly misreprented the car in his ad and on the phone. When my friend told Jim that he had misrepresented the car Jim said that he would basically say whatever it takes to get people out to look at the car.
I didn't mention this earlier cause I'm giving Jim the benefit of a doubt.
I dealt with him before on a turbo for a BMW. Not only his kits won't fit in the car, he refuses to return the money. We had to go through the credit card company to get our money back.
I dealt with him before on a turbo for a BMW. Not only his kits won't fit in the car, he refuses to return the money. We had to go through the credit card company to get our money back.
Unfortunately my friend had sent Jim a $500 deposit. He refused to give my friend the money back when we were there. Jim said that he would have his secretary mail it out. So will see if he sends it.
BTW, I thought that turbo kit on the car was poorly done as well. They even put one exhaust tip so close to the rear valence that the paint was bubbling.
[This message has been edited by BA94NSX (edited 24 May 2002).]
BTW, I thought that turbo kit on the car was poorly done as well. They even put one exhaust tip so close to the rear valence that the paint was bubbling.
[This message has been edited by BA94NSX (edited 24 May 2002).]
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