Help with my GT500!

Discussion in 'Boss 302 and S197 Technical Forum' started by cgaulzetti, Nov 18, 2018.

  1. cgaulzetti

    cgaulzetti TMO Intermediate

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    Hi Guys:
    I've decided to keep working on making my GT500 the best handling most fun car I can. I've always wanted it to be a race car for the road- and after the suspension work that I've done, the NT01 285/40/r18s on all four corners on 18x11s, it's almost there. It has ST Coil-overs and camber plates, Whiteline LCA, etc. I also have a FAYS2 watts link that I haven’t installed yet. Honestly the thing handles really great. I loaned it to a buddy who has a new GT350 and he threw the keys back at me pissed off because he said my pig handles far better than his car!


    We also did the TVS upgrade, with a new heat exchanger, a MacLeod RXT clutch, a Boost-a-Pump, a big JLT CAI, and a dyno tune and the power is great.

    I'm going to gut the interior and get Autopower Industries to do a custom cage/roll bar for the thing. We'll pull out the stupid DVD player dream of the early 2000s hi-fi system the previous owner put in the thing, and finally install my Barton shifter. It will be nice to have no rear seats and plenty of room to lug my CF5 Hoosier track wheels to and from track days!

    My question for you guys is for a street legal race car- say I'm going to have a catless offered X-Pipe installed and re-tune- I figure I'll need to put some axle backs on there- any suggestions?

    Also do you guys have a favorite fixed back seat? I like the price of the Corbeaus but are Momos or Sparcos or Cobras worth twice as much money?

    Any hints on ripping up carpets, removing door panels, and four versus six point roll bars?

    Any other advice on how to make a GT500 less of a pig? Or maybe a little bit more of a lean wild boar maybe? Carbon hoods, trunk lids, doors, quarter panels, light batteries, carbon driveshafts, Lexan windows, what should the order of priority be?

    Is there any suspension/chassis stuff I’m missing? I did engine/tranny mounts in previous cars- is that worth it?

    I've got a NASCAR style blade spoiler that I know won't provide as much down force as a good wing- but with a good wing I think I'll need to add a matching big front spitter too- which could be in the cards...not sure though. It is also important what the thing looks like- and a stripped down NASCAR/Trans-Am appearance appeals to me more than a GT or PikesPeak car with a bunch of active aero.

    Thanks for your thoughts!

    Powered windows and mirrors actually don't weigh that much.....the AC unit does though!

    How do I make my GT500 even better?

    Thanks!
    Craig
     
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  2. VoodooBoss

    VoodooBoss Rick Moderator

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    Welcome to TMO and it looks like you're off to a great start. I installed a CorteX watts link on my Boss 302 and really liked how the car felt. I don't think it made me any faster but it made the car more predictable.

    As for the RSD there are many options. I used the one from Watson Racing and it worked well with my X brace and rollbar.

    @ArizonaBOSS and @captdistraction might have some ideas on removing the interior as they both turned their cars into race cars.
     
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  3. domesticpower

    domesticpower Track Addict

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    Really like what you're doing! Looking forward to what you end up with. My Boss 302 surprises a lot of people, even on stock suspension (albeit, with a couple mods).

    I have the Fays2 Watt's link too. I'll give you a heads up, it's tricky to "tune". You might luck out at the first try and set the angles perfectly, but I was adjusting it every one or two track days until I found the height and the angles that work. It's a very stout and well built unit, though, and makes a big difference in how settled the rear end feels. It won't improve the performance of the car a whole lot like VoodooBoss said but it'll make the car feel a lot more trustworthy and you'll likely be more comfortable to go faster. Fays2 was fantastic to deal with, too.

    I have heartthrob flowpak axle backs. They're not SS, only alum. steel, so they don't look the nicest. No chromed tips either. But I lost count of how many times people have told me "your car is the best sounding car here!" at our track. My exhaust is otherwise all stock, aside from baffling plates taken out from the OEM Boss 302 side pipes. Those axle backs are also thin walled and have glorified resonators for mufflers, barely more than a straight pipe, so they saved 20 or 25 lb. compared to stock axle backs. Aside from the mediocre looks, the only other "issue" with them is that they drone badly at 1800-2000 rpm, but it sounds like you won't be spending much time in that range... lol

    I completely agree with you on the Trans Am look with a deck lid spoiler, even if it is less efficient and less effective at generating downforce. It looks great.

    These cars two biggest weaknesses IMO is the weight and the engine location above the axle (also weight related). You need a lot of tire. If you have 18x11's, I'd go higher than 285's. Maybe 295 or 305 up front. My car also likes a lot of camber, not sure what you're running but I see you have plates.

    Does the GT500 come with a diff and trans cooler? You might want to look into those.

    You're going to save a lot of weight from the interior, wheels, and seats. I'm not sure if CF will pay off if you're thinking of bang for the buck. But if you just want to go all out, that would be cool to see! Keep in mind that a lot of CF parts don't fit well, though, and it's very hard if not impossible to find shops that work with it locally (depending on where you are) so make sure you research who you're buying from and the quality of parts they make.

    If you're at a high speed track, I'd say aero would pay off better than weight saving (beyond gutting the interior, the seats, and the wheels), especially on a GT500 that can make serious speed. Aero would help a lot on high speed corners if you have them.

    Hope this helps! Looking forward to seeing the progress.
     
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  4. cgaulzetti

    cgaulzetti TMO Intermediate

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    That helps a ton! Thanks!

    Some clarification: The car currently has no axle backs but has the cats and the stock x pipe and headers. Our plan is to install an JBA Off-road X-pipe and do a new dyno tune- but I think I'll need some type of axle back then because it'll be too loud.

    i do drive the car on the road so i don't want it to be TOO obnoxious and I think an off-road catless X pipe with no mufflers will be a bit much. I love the idea of the heartthrob axle backs you did! Those look awesome and I love the idea that they're light and don't look shiny an fancy. This car in my head is all about function. When I got it- it had tons of taped on weird body stuff- totally garish silver grills that weren't doing anything except covering the stock grill, probably impeeding airflow and looking really stupid while they added a bunch of weiht. It also had 20" wheels and was meant to look like an "Elenor" car. I'm sure the previous owner thinks I've ruined it though!

    Thanks for the advice on the Fays2. It sounds like a giant time consuming pain in the ass to install from what I've heard. My shop quoted me five hours of labor. I don't have a lift right now- but did you install it yourself? How was it?

    Should I just pay someone else $500 to $600 to put it on and do it right?

    I agree that replacing a bunch of stuff with carbon for weight savings is going to cost a lot for very little return. I like the idea of exploring aerodynamic stuff although I'm actually really psyched about putting my big five star blade spoiler on it. I've just been cheap and need to actually just stop waiting to find a v6 mustang in the junk yard to steal a trunk lid off so I have a clean one with no holes in it to mount the spoiler to.

    I forgot to mention that my track wheels are forgeline custom CF5s i got from Sam Strano and I got some Hoosier/Continental Superspeedway slicks for them. They're not as grippy as most slicks because they're designed for longevity for big heavy cars at tracks like Daytona- but I figured for track days they'll be great for me once they get heated up. They're 305/685/18 G5000. I haven't mounted them yet- but I'm pretty excited!

    I wound up ordering some Kirkey 55 seats from Summit and the adjustable mounts from Fathouse Fabrications. We're going to get those drop-shipped to the guys at AutoPower here in San Diego who are going to weld in either a four or a six point cage/roll bar set up in the car. I assumed I'd want everything welded in but the guys there mentioned that it is really slick to have the removable cross brace- because it makes it a lot easier to lug your tires and other stuff to and from the track.

    It's really great car though.
     
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  5. Grant 302

    Grant 302 OPM Spent: $587,402 Moderator

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    What pads are you running? ...and I didn't see brake ducts mentioned.

    Weight reduction on a street car comes down to whatever you can live with.
     
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  6. domesticpower

    domesticpower Track Addict

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    Craig, I'm happy to help! I'm going to break up your response and insert comments to make it easier to read.

    That's true. No cats or mufflers will probably be obnoxiously loud at times if you also want to enjoy it on the street at times. Make sure to also check with your track if you have sound dB limits. I can't remember how much exactly those heartthrob axle backs saved. I dug up my numbers from when I changed it and it weighed 22 lb. less than stock!

    I know what you mean about weird body add-ons. I've seen some pretty excessive panels, scoops, grilles, etc. and I completely agree that they look garish. But to some, we do ruin our cars. To each their own!

    I installed it myself with the car on ramps in my driveway. It wasn't fun... but almost no installation on ramps is! It wasn't a whole lot worse than LCA's which I see you have. If you've done those yourself, you should be able to tackle the watt's link, it just takes a little longer.

    The challenge with the watt's link is getting the angles right to avoid any binding and give the widest range of motion possible for the spherical joints without hitting the rubber o-rings. I tried doing it with a digital angle level app on my phone to get it more accurate, and it still took tweaking. If the rubber o-rings become regular bump stops, they'll break apart in no time. Then, you get into picking which bolt hole to mount the "propeller" link, which moves your rear roll centre and changes how much rear axle steer you have. If you move the bolt hole to tune it after the install, you'll have to tweak the angles again to find the right spot.

    If you get a shop to do it, you'll still have to do the tuning and adjusting yourself, unless you get the shop to do it every time, which could get expensive.

    I hadn't heard about Five Star blade spoiler before. That sounds like a great plan to find a trunk lid from a junked Mustang and drill it. It looks substantial and I would imagine you might need some form of front aero, at least a small splitter, to balance downforce on the front axle if you have a very high speed turn and the car might just run wide and you have to slow down anyway.

    I love the idea of longevity. I don't like hero tires that do a few laps and get greasy or a couple of track days and get worn/heat cycled out. It sounds like you're on track for a great build. I'll be looking forward to where it ends up!
     

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