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Longitudinal Engine

Joined
8 October 2004
Messages
626
Location
London, UK
Hi Guys,

Anyone know of a longitudinal NSX conversion (bar Super GT cars)? If so we're hoping to save some time/effort with any advice you may have. Also if they fitted a sequential box this would be useful, particularly if they kept the wheelbase standard.

Kind Regards,

Rob
 
Rob, It seem's from the listing of cars on your post, that you know a thing or two about great cars....what would be the benefits of a Longitudinal engine in an NSX?
Secondly, where would it fit, the engine bay is so small.

Bram
 
Hewland made a sequential for JGTC cars which was a direct replacement for the OEM (transverse)box. So no real need to re engineer to a north/south set up. Later JGTC IS north/south. I'm sure you are aware. I'd contact Dome the chassis maker in Japan or Hewland in England directly. Good luck !!
 
I've never heard of such a thing. With the space in the NSX, you would almost certainly have to carve the trunk out and put the transmission in that space, behind the wheels. Even then, I doubt there would be enough room for the engine without completely rebuilding the back end and moving the wheels back.

Unless you want to pretty much go the same route as the JGTC guys and build a tube frame, then build a NSXish body on top of it, I think you're out of luck.

I'm really curious to know why you would want to try something like this.

Nick
 
We have a Quaife sequential in the Elise and it is very poorly made, so i don't have much faith in them for an NSX. I live 5 minutes from them and even then their support is poor. In fact i found this quote on another forum about this particular gearbox which is in keeping with our own experience:

"If you go sequential , dont go quaife 32G they go vroooom tic vrooooom tic vroooooooom BANG grrrrrruncccchhhhhhh -------oil slick!"

That quote is from owners with old Vauxhalls (GM) which barely have over 250bhp if that.

I was aware that Hewland are the manufacturers of the JGTC gearboxes but we have also tried them too, no transverse gearbox they do takes much more than 300bhp. It makes me wonder if the GT300 actually had a sequential at all..? I can't imagine that they would have been using under engineered gearboxes.

And yes we're aware we can't just drop in a longitudinal layout ;) Why do we want to do it? To be different...
 
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Anyone know of a longitudinal NSX conversion (bar Super GT cars)?

Two words: Custom fab.


It makes me wonder if the GT300 actually had a sequential at all..?

They use a Hewland.


I can't imagine that they would have been using under engineered gearboxes. And yes we're aware we can't just drop in a longitudinal layout ;) Why do we want to do it? To be different...

FYI, the GT300 vehicles preserved the original transverse layout. You might be think of the the twin turbo Honda GT1, which had a longitudinal layout.


Why do we want to do it? To be different...

Wrong reason. Still, not a problem so long as your annual racing budget is equally as different. :wink:
 
There is not room to go longitudinal with the slight possibility for a very short driver moving the firewall forward a WHOLE lot. A number of cars that were transverse went to longitudinal for race versions due to available race trannies, thats probably the situation here. Could Hewland build a high HP transverse tranny? Probably, but if you add syncros the cost would probably be 50k or more.(?) Anyone ask Hewland?
 
You could do it with a custom sub frame and rear control arms and gutting the trunk for more room.

Their aren't too man sequential transmissions that can handle the HP and torque that some turbo NSXs are currently making. PTG blew up many Hewlands with ~450bhp in their GT cars and not a lot of torque.

These trannies can be $40-80K+ Money is better spent elsewhere IMO.
 
The head scratching is over matching driveshafts with wheelbase. We were already doing new suspension arms for the centre locks so the project is just kind of snowballing.

From what i've seen the Hewland PCT gearbox takes 250lbs/ft which would have been barely enough for the JGTC300 cars unless they were rebuilt every race! A possibility i guess....

Anyway, thanks for the input. Looks like transverse is not an option.
 
You could do it with a custom sub frame and rear control arms and gutting the trunk for more room.

QUOTE]

Well you'd have to move the wheel openings back say 6 inches or more just to be at the back of the engine, much less allowing for the tranny, and thus the wheelbase. I don't think you can angle the driveshafts forward more than a couple of inches. (?)
 
Well you'd have to move the wheel openings back say 6 inches or more just to be at the back of the engine, much less allowing for the tranny, and thus the wheelbase. I don't think you can angle the driveshafts forward more than a couple of inches. (?)
because the gearstack sits aft of the half-shafts, only the clutch and bell housing would add additional length to the wheelbase. The nsx v6 is pretty square so I wouldn't think itd be a problem. They did it on that alms gt nsx usung the parameters of the stock cabin and firewall, tubbing the rear of the car and it dosnt appear the wheelbase on that car is longer than stock...
 
I believe that you guys keep thinking of engine/trans arrangements ala Pantera and F355, which have the trans rearward of the engine. I believe the GT500 NSX had the trans forward of the engine, next to the driver and a short driveshaft going back to the diff, which was in the current place in the car, now next to the sump of the reverse facing, but still north-south, engine. This package is a tad more complicated but utilizes available space better without drastic changes to the platform and also moves weight distribution forward for better handling. My Cosworth Escort WRC car has the front diff mounted as part of the engine oil pan with one of the front driveshafts going through the pan and the diff driven by a shaft coming forward from the transfer case part of the trans. The whole thing could be easily reversed and fit into my NSX without, I think, even cutting into the trunk, or damn close. Come to think of it, that might be cool, 500+hp, 420 ft/lb lighter 4 cly Cosworth powered NSX-hmmmm. Tony
 
I've looked into something like this before, but quickly decided against it with my relatively pristine 1992. It would be fun to try on a totally lost-cause Salvage title NSX and someday I may try it. However, I had planned on removing the fuel tank and sliding the engine forward 12". The overall length of the block itself is around 20" which left 20-24" of space behind the plane of the bell housing to fit a gearbox/differential.
 
Just wanted to post that I have some experience in some "extreme engine swaps", so I wasn't joking around when I said I had looked into it...

laddershot.JPG
 
I believe that you guys keep thinking of engine/trans arrangements ala Pantera and F355, which have the trans rearward of the engine. I believe the GT500 NSX had the trans forward of the engine, next to the driver and a short driveshaft going back to the diff, which was in the current place in the car, now next to the sump of the reverse facing, but still north-south, engine. This package is a tad more complicated but utilizes available space better without drastic changes to the platform and also moves weight distribution forward for better handling. My Cosworth Escort WRC car has the front diff mounted as part of the engine oil pan with one of the front driveshafts going through the pan and the diff driven by a shaft coming forward from the transfer case part of the trans. The whole thing could be easily reversed and fit into my NSX without, I think, even cutting into the trunk, or damn close. Come to think of it, that might be cool, 500+hp, 420 ft/lb lighter 4 cly Cosworth powered NSX-hmmmm. Tony
Look at the video 1:01-1:09 into it. You can see the rear suspension setup with the lower control arms bolting to the transmission that is laid out ala Pantera, F355, any mid-engine racecar utilizing the transmission as a stress member and the mounting point for the rear control arms (in this case, only the NSX's rear lower control arm).
 
That's the '95 LeMans car, I agree it looks normal longitudinal mid engine rear trans. I was referring to the GT 500 cars run in the JGTC, Super GT. I believe I have read plenty of discussion and reviews of these cars stating drivetrain with trans forward of the engine. This actually makes sense for plenty of reasons and wouldn't be that hard to do, though I would also only consider a clean high mileage car for the exercise as when you're done, no matter how nice, it's likely to be worth no more than when you started. Having just taken plenty of laps at Road America (without spinning out) last weekend, I am pleased as can be with my modified but stock drivetrain layout '94.
 
Hewland made a sequential for JGTC cars which was a direct replacement for the OEM (transverse)box. So no real need to re engineer to a north/south set up. Later JGTC IS north/south. I'm sure you are aware. I'd contact Dome the chassis maker in Japan or Hewland in England directly. Good luck !!

First of all, I am not very familiar with the JGTC NSX's, but I do know the engine and trans lay-out is completely different from a stock NSX.
I also know that the JGTC cars are, of course, specifically made and tuned for those races, which really don't last very long.

When Honda had a original JGTC competing in the Nurburg 24-hour race the car itself was doing excellent, but it dropped out of the race because the Hewland transmission gave up. Which, by the way, was exactly what people 'in the know' expected would happen.
 
That's the '95 LeMans car, I agree it looks normal longitudinal mid engine rear trans. I was referring to the GT 500 cars run in the JGTC, Super GT. I believe I have read plenty of discussion and reviews of these cars stating drivetrain with trans forward of the engine. This actually makes sense for plenty of reasons and wouldn't be that hard to do, though I would also only consider a clean high mileage car for the exercise as when you're done, no matter how nice, it's likely to be worth no more than when you started. Having just taken plenty of laps at Road America (without spinning out) last weekend, I am pleased as can be with my modified but stock drivetrain layout '94.
Super GT NSXs have the same transaxle layout as the LeMans car, formula cars (which Super GT are closer to bodied formula cars than production cars), or any other purpose-built mid-engine car/race car.
 
Everything I have read about the latest Super GT cars, I think starting in about 2002 would disagree. The first gen JGTC, 300 and 500, were transverse like the production cars, but the newer gen "Super GT" cars have been described countless times with trans forward. These cars are as much NSX as NASCARS are production sedans. Whatever you choose to believe, traditional rear transaxle would seem to be going out of favor with many designers as they discover that front engine/rear transaxle (Alfa certainly new this in the late 70's as their transaxle cars handled beautifully) seems to provide good weight distribution, especially with the trend toward awd super sedans, and polar moment stability at high speeds, and, I guess, possibilities of a rear seat. Rotation, however, can be more difficult in larger cars with longer wheelbases. My Alfa does not have any problems in this area as it is fairly short wheelbase and very light. Corvettes seem to do OK, but I haven't driven one hard, and I wonder how heavy sports sedans like the GTR make it work, maybe the AWD makes the difference. I know I can feel the front wheels pulling the front end where I want it to go when I start to accelerate at the apex of a turn in my Cosworth Escort. There will always be those who, with enough careful engineering, can make any combination work, Porsche for example, but the trends come and go. I still like traditional mid engine best, but were I to try to fit something else (I'd have to think of why I'd make major changes just to use the existing engine, but maybe if Honda comes out with a V8 or V10) in an NSX shell with a free hand I'd seriously look at backwards engine with trans forward.
 
Everything I have read about the latest Super GT cars, I think starting in about 2002 would disagree. The first gen JGTC, 300 and 500, were transverse like the production cars, but the newer gen "Super GT" cars have been described countless times with trans forward. These cars are as much NSX as NASCARS are production sedans. Whatever you choose to believe, traditional rear transaxle would seem to be going out of favor with many designers as they discover that front engine/rear transaxle (Alfa certainly new this in the late 70's as their transaxle cars handled beautifully) seems to provide good weight distribution, especially with the trend toward awd super sedans, and polar moment stability at high speeds, and, I guess, possibilities of a rear seat. Rotation, however, can be more difficult in larger cars with longer wheelbases. My Alfa does not have any problems in this area as it is fairly short wheelbase and very light. Corvettes seem to do OK, but I haven't driven one hard, and I wonder how heavy sports sedans like the GTR make it work, maybe the AWD makes the difference. I know I can feel the front wheels pulling the front end where I want it to go when I start to accelerate at the apex of a turn in my Cosworth Escort. There will always be those who, with enough careful engineering, can make any combination work, Porsche for example, but the trends come and go. I still like traditional mid engine best, but were I to try to fit something else (I'd have to think of why I'd make major changes just to use the existing engine, but maybe if Honda comes out with a V8 or V10) in an NSX shell with a free hand I'd seriously look at backwards engine with trans forward.
Do you really believe everything you read on the internet? Most information is opinions and not facts. If I believed the internet and magazines, the Spoon NSXR-GT and the Factor X NSX are both twin turbo (I still can't find the second turbo on either car... :confused:)

Their was some miscommunication, but I believe I mentioned Super GT referring to the GT500 NSXs and not the JGCT GT300 cars which as you explained have a transverse layout. Longer wheelbase racecars are more stable and faster for the types of circuits that Super GT competes at.

:50 seconds into the video you see the cockpit where their is no transmission forward of the engine (ala: Porsche rear engine cars). It's a traditional transaxle layout.
http://www.youtube.com/watch?v=-6g_m5yrEtU


A transmission forward of the engine dosn't make sense on so many levels and their's a reason why you don't see that layout on any proper-built mid-engine cars. I would be surprised if you could find a picture of any proper longitudinal mid-engine car with the transmission forward of the engine (short of a Murcialago). The Murcialago is a terrible example of a performance car. It's drivetrain is poorly laid out, overly complex, too heavy, and it's performance is over-shadowed by it's little brother - Gallardo. I was unfortunate to help pull the motor/transmission of a Murcialago and the build quality was very poor. Flimsy chassis braces, box-tube frame chassis with uneven welds that skipped 15mm between two chassis members in multiple places! The Gallardo on the other hand is a proper mid-engine transaxle layout and is a much more competent and better designed car for the track.

Corvettes and GTR are front-engine transaxles. Apples to oranges with a mid-engine (Transverse or longitudinal transaxle) cars.

0.02
 
Pretty late jumping onto this thread but one of our customers made a longitudinal V6 engined NSX registered for the street and it was displayed at the Tokyo Salon 2010. They are based in Kobe.
 
Hi Guys,

Anyone know of a longitudinal NSX conversion (bar Super GT cars)? If so we're hoping to save some time/effort with any advice you may have. Also if they fitted a sequential box this would be useful, particularly if they kept the wheelbase standard.

Kind Regards,

Rob


04.jpg

EspiritNSX_engine_bay.jpg


Route KS did one a while back... but the project was crushed...


EDIT:

<iframe title="YouTube video player" width="480" height="390" src="http://www.youtube.com/embed/egHK5-n2e-s" frameborder="0" allowfullscreen></iframe>
 
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