Guest JAMIE T Posted April 24, 2001 Share Posted April 24, 2001 I am thinking about stretching the front of my 240 about 4" to come to a closer wheelbase of the real GTO's. I am building a new front subframe anyway, so I figured this would be a good time to do it. I don't think stretching the fiberglass after the front wheel well should be a big deal(I have fiberglass experience) What do you guys think? Jamie Quote Link to comment Share on other sites More sharing options...
pparaska Posted April 24, 2001 Share Posted April 24, 2001 I've heard of this being done, as this is probably the largest place where the 240Z and the GTO 250 don't agree in proportion. I know a guy with a Daytona Cobra kit on a 240Z and he did the same thing to make it look closer to the real thing. I say, go for it! Quote Link to comment Share on other sites More sharing options...
Guest Frank280z Posted April 24, 2001 Share Posted April 24, 2001 Jamie, How will fab the front end? Like Terrys Blue Oval Z? With foam and hand laid glass? This is the method I'm using on my hood. Any tips on the resin or types of cloth? Thanks Frank Quote Link to comment Share on other sites More sharing options...
blueovalz Posted April 24, 2001 Share Posted April 24, 2001 What parts of the front clip do you want to extend. The part behind (rearward) the front wheels (i.e extending the wheel base)? Or perhaps a little on both sides of the front wheels? Terry Quote Link to comment Share on other sites More sharing options...
blueovalz Posted April 24, 2001 Share Posted April 24, 2001 With all else being equal, extending your wheel base forward should slightly improve the ride quality over bumpy roads, bias the weight distribution toward the rear, and I think the polar moments will improve being the front tires will be moved further away from the center of mass. In other words (and I'm waiting for some more knowledgeable advice here) there should be an improvement in handling, if only minor. The bodywork may be a challenge being the GTO is just a bundle of compound curves (beautiful curves), so being able to extend these will take some good eyeballing in order to blend the different radii (spelling?) when adding (splicing) material here. Terry Quote Link to comment Share on other sites More sharing options...
Drax240z Posted April 24, 2001 Share Posted April 24, 2001 Hmm, I think polar moment of inertia is dependant on the distance from the object in question, to the center of gravity of the vehicle, and is independant of where the wheels are. Though the other way makes sense too. Pete? Quote Link to comment Share on other sites More sharing options...
pparaska Posted April 25, 2001 Share Posted April 25, 2001 O.K., I'll take a WAG at this polar moment of inertia (PMOI) thing. Terry's comment is interesting. lenghtening the car does impact the PMOI, since the CG will move forward from the rear wheels if the engine is in the same place relative to the back of the car and the car is lengthened in front of the engine/firewall. The difference being that the engine is now closer to the for/aft CG location, but the front suspension/wheels/bodywork is farther. So it really comes down to looking at the effects of the changes of those things on the PMOI: PMOI(engine)= engine mass (times) Xcg (times) Xcg where the Xcg is the distance from the engine center of mass to the car's center of mass. Do that calculation for both wheelbases and you'll see the number go down since the Xcg is shorter for the lengthened car (lengthened in front of the engine) But you need to see the affect on the PMOI of the stuff you moved forward: PMOI(front stuff) = mass of front (times) Xcg (times) Xcg again, Xcg is the distance betweeen the center of mass of the "front stuff" to the car's CG. So, hack the stuff off just behind the front crossmember, and add the distance you'll move it to the old distance from it's center of mass to the car's CG. You should also calculate the added PMOI of the added section from behind the crossmember to where you cut. Anyway, do the accounting and see what happens. Yes the engine is heavy, but it's close to the CG of the car. The "front stuff" you cut off and move (and the bit you add) is probably as heavy or heavier than the engine, but it's Xcg distance is a good bit greater and it gets squared in the PMOI equation, so it probably has a larger impact on the PMOI. I've kind of convinced myself from the above that the PMOI of the car is going to be greater if you add a section between the crossmember and the firewall, even if you leave the engine in the same place relative to the firewall. BUT, the front tires are now a bit farther from the CG (I'd guess) and they therefore have a greater ability to put a moment or torque about the CG. So maybe it's all a wash? Now I'm confused again. Quote Link to comment Share on other sites More sharing options...
Guest JAMIE T Posted April 25, 2001 Share Posted April 25, 2001 O.K. guys, I am completely confused(yes it is getting late) The engine will remain as close to the firewall as it can. If I move the front suspension forward, I can imagine that the ride would improve slightly. I don't think that the handling will be greatly affected, but I am no engineer(Pete) My question now is, do you guys think this would be worth the trouble? And, does a greater PMOI add to improved handling? To weigh the pros and cons, on one side the car will look more like the originals, then again, I will have to re-work a nice piece of fiberglass with difficult curves. If the handling is not to be affected in a bad way, it seems like it would be a good modification. The tubing for the frame rails has been ordered(2"x3" .083"), and should be delivered tomorrow. Cutting will not begin for a couple of weeks though. The engine I will be using is a very light aluminum v8 about 425lbs- complete. The section added will be between the crossmember and the firewall. I hope this info helps with anymore replies. Jamie Quote Link to comment Share on other sites More sharing options...
Drax240z Posted April 25, 2001 Share Posted April 25, 2001 Greater PMOI is going to -hurt- your handling, not help it. What polar moment of inertia is, is the tendancy for your car to spin around its center of gravity. The greater your PMOI is, the more torque that is acting to make your car spin. I'm pretty sure that PMOI won't be effected by the wheelbase increase, but WILL be effected by the increase in distance from the Cg. The end result, your PMOI will be higher than before. But, as Pete said, the tires being furthur away from the Cg should act in the opposite manner than the increased PMOI does. I think the final result will be that your PMOI increases related to the square of the distance, while the torque increase from moving the wheels furthur will increase linearly with the distance. So in the end, you'll hurt your handling a bit. (if I am right, and who knows?) Quote Link to comment Share on other sites More sharing options...
Guest JAMIE T Posted April 25, 2001 Share Posted April 25, 2001 Thanks guys for posting. I am thinking about stretching the wheel base. This will be done between the front wheel well and the door. Apparently the 250 GTO has about a 4" longer wheel base. I was reading some old posts about what Pete mentioned about the Daytona, and that it had been done. I am fabing a new front subframe for the car anyway(like Rons Drag Car) This should also help me fit that big Northstar Cadillac It shouldn't be too much work to lengthen that section of fiberglass either. May Terry can tell me how this will affect handling, as this will be an issue for me. Thanks, Jamie Quote Link to comment Share on other sites More sharing options...
SpeedRacer Posted April 28, 2001 Share Posted April 28, 2001 You could try one of these instead http://www.reinaintlauto.com/65gto811.html kinda like the ultimate Ferrari GTO kit. Quote Link to comment Share on other sites More sharing options...
pparaska Posted April 29, 2001 Share Posted April 29, 2001 quote: Originally posted by JAMIE T: ...My question now is, do you guys think this would be worth the trouble? And, does a greater PMOI add to improved handling? To weigh the pros and cons, on one side the car will look more like the originals, then again, I will have to re-work a nice piece of fiberglass with difficult curves. If the handling is not to be affected in a bad way, it seems like it would be a good modification. Jamie That's a tough one. I tihnk it's a really cool idea to try to imitate the true proportions of the GTO250. Bute whether it's worth it, I dunno. Looking a SpeedRacers GTO 250 replica makes me think I'd just do it that way. Personal decision I can't help with. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted April 29, 2001 Share Posted April 29, 2001 IMHO, as Pete said, alot of work just to try and maintain something true to the original. It'll fool many non ferrari people, and the ones that know anything about ferrari's would know in a instant its not the real deal anyway, so why the extra work. Speed Racers is about as nice a example as there is. As I said, just an opinion, if its your own desire to have it as scale as possible, then by all means, I wish you well on the project and hope it turns out as you desire it because in the long run, thats all that matters. I personally get a giggle driving my converted 240z V8 just because I know I put it together 100% myself with no help (with the exception of the tireless questions and answers from this great group of people here at HybridZ), the fact that it drives as well as it does tickles me to no end. Good luck with it! Respectfully, Lone Quote Link to comment Share on other sites More sharing options...
Guest JAMIE T Posted April 30, 2001 Share Posted April 30, 2001 Thanks guys for the input. I actually think that real 250 GTO's look a little long in the front anyway, I just wanted bench race the idea with you guys, and see if it plausable(sp?) But, I don't want to build an ill handling car, just to get correct proportions. Your definatly right Lone, about most people not knowing the differance. I can see it now, A ricer pulls along side of the Northstar powered Ferrari GTO, revs his motor for his under age girlfriend, and quickly gets wasted, all he see's are a couple of (very small by this point) tail lights. I'll let him go brag to his friends about how he got dusted by a Ferrari(If he lies I will hunt him down and kill him) Its just, people don't mind getting beat by a Ferrari!!! Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted May 1, 2001 Share Posted May 1, 2001 Yeah, with that Northstar in there, thats going to be a sweet looking and fast car. Lone Quote Link to comment Share on other sites More sharing options...
Guest Daddyrick Posted May 1, 2001 Share Posted May 1, 2001 You are right about the GTO being longer, but to stretch the kit would require a lot of work to "look" correct. I have the Stable Autoworks kit and the front does not lend to just lenthening a certain section. It would take a great deal of work to keep the correct curves, but it would look nice. For those interested in the GTO, I suggest you buy or borrow a copy of Ferrari 250 GTO by Keith Bluemel. There is enough difference in the detailing of each car that one could say that there is no exact standard to copy, so that is what makes these kits so nice. Quote Link to comment Share on other sites More sharing options...
Guest spartacus80202 Posted May 20, 2007 Share Posted May 20, 2007 I agree, strecth the car to make it closer to a real GTO 250. The nose sits lower on the Ferrari and it is longer. I you lower the headlights on the Thunderranch kit and stretch the nose 2 to 4 inched I think you'll have a sweet ride. Maybe Oxandale can give some Fiberglass forming pointers. regard! Quote Link to comment Share on other sites More sharing options...
chelle Posted May 21, 2007 Share Posted May 21, 2007 Our's is stretched- it does change a lot about the look, but it's still not the same proportions as an original, for that you'd need to also take out some length from the cabin, and add more to the front. Just make it how you want it - If you feel comfortable stretching the go for it - just make sure you make it strong enough to keep going straight. We have pics showing where we added the length to the front posted on this site. Chelle Quote Link to comment Share on other sites More sharing options...
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