ST4/TT4 Thread
So who is going to go this route? The 2017 rules are posted and seems like we could have a similar deal to STL if anyone takes advantage of it.
https://nasa-assets.s3.amazonaws.com...--10-31-16.pdf FWD has quite a tax break at +.6 mod factor. Todays PTE/PTD cars could become very fun by taking out your 200#s of ballast to make up for the extra Pwr:weight. My my current car at 2210 can run at 192whp vs 141whp. While taking limitations off brakes, tire size up to 245 vs 205, and typical nice updates including NB subframe, spindles, and bumpsteer. Can do more than double adjustables and gear ratios are also open. Fwd cars on 245s or smaller while under 2600# and over 2200# will have 1.1 additional factor on any rwd car. Enough for a free sequential/dog box, "A" tires, or 10-12whp. Average hp is another piece of the puzzle. |
Wow, I'm very surprised there wasn't a break for 225mm tires, hah.
This would be a very fun class to run, but a lot of development to get towards the pointy end of it. 2400lb NB @ 208rwhp ...... average. On 245 R7s, 15x10s, front air-dam & splitter, rear wing..... damn. |
I only skimmed the rules twice, but I'm not seeing any way for a swapped miata with an aftermarket subframe to run ST4. Aftermarket subframes work in ST1-3 with the non-production mod factor, but that mod factor can't be used in ST4. Looks like unmodified OEM subframe is required.
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Originally Posted by jpreston
(Post 1371678)
I only skimmed the rules twice, but I'm not seeing any way for a swapped miata with an aftermarket subframe to run ST4. Aftermarket subframes work in ST1-3 with the non-production mod factor, but that mod factor can't be used in ST4. Looks like unmodified OEM subframe is required.
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Originally Posted by jpreston
(Post 1371678)
I only skimmed the rules twice, but I'm not seeing any way for a swapped miata with an aftermarket subframe to run ST4. Aftermarket subframes work in ST1-3 with the non-production mod factor, but that mod factor can't be used in ST4. Looks like unmodified OEM subframe is required.
"7.3.2 Restrictions and Limitations for Production Vehicles Only: 1c) Suspension sub-frames/suspension cross-members may be updated or backdated utilizing any OEM factory produced item that is a direct replacement piece for that model, regardless of year or street legality, provided that it can be installed in the same location and in the same manner as on the donor vehicle without modifications. " |
So NB subframes in an NA are kosher, but the V8R subframe isn't. :(
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Originally Posted by aidandj
(Post 1371680)
Ecotech swap
Even still, in ST with 245s and aero..... you'd probably be better off running 2550lbs+ @ 220rwhp avg. |
You have a lot better shot at it than with a bp.
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Originally Posted by The Rulebook
7.3.2 C:
2) Relocation of suspension mounting points is permitted in ST1, ST2, and ST3, provided that the modifications do not violate any of the other rules above. One possible method is via the use of modified mounting point brackets attached to OEM mounting locations. Relocation of suspension mounting points is not permitted in ST4. That means NO NB subframe/spindles/bumpsteer in 4. Only in 3/2/1 |
Excerpts:
Under: 2200 lbs = -0.3 2600 lbs = -0.2 3000 lbs = -0.1 Over: 3300 lbs = +0.1 3400 lbs = +0.2 3500 lbs = +0.3 3600 lbs = +0.4 3750 lbs = +0.5 3900 lbs = +0.6 245 or smaller = +.7 250 to 275mm = +0.3 windshield removal = -.3 OEM aero = +.4 Sequential = -1 A7/R1S/C91 = -1 __________________________________________________ ___ Imagine this: OEM-aero, Ecotec, NB 12:1 base 12.2:1 2201-2599lbs 11.5:1 245 or smaller 11.1:1 Oem aero 200whp/2225lbs Wow. |
Originally Posted by doward
(Post 1371835)
Excerpts:
Under: 2200 lbs = -0.3 2600 lbs = -0.2 3000 lbs = -0.1 Over: 3300 lbs = +0.1 3400 lbs = +0.2 3500 lbs = +0.3 3600 lbs = +0.4 3750 lbs = +0.5 3900 lbs = +0.6 245 or smaller = +.7 250 to 275mm = +0.3 windshield removal = -.3 OEM aero = +.4 Sequential = -1 A7/R1S/C91 = -1 __________________________________________________ ___ Imagine this: OEM-aero, Ecotec, NB 12:1 base 12.2:1 2201-2599lbs 11.5:1 245 or smaller 11.1:1 Oem aero 200whp/2225lbs Wow. |
EFR BP with flat 200hp from 4000rpm to 8000rpm?
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Originally Posted by aidandj
(Post 1371852)
EFR BP with flat 200hp from 4000rpm to 8000rpm?
The junkyard Ecotec swap could be "Spec ST4" thing, ultimate dirt cheap/go fast combo. |
I also don't see 200 "average" hp from an ecotech being easy or cheap.
I dont know the exact calculations for average hp, but with really good boost control you can add/remove power in specific locations and even tune your setup per track. |
Junkyard Ecotec would be far from optimized for ST4 but could still be quite competitive in most regions. Sort of like dyno classed, junkyard motored PTE NB1's. Butts kicked at East/West Champ but snagging wins/lap records regionally.
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Originally Posted by Savington
(Post 1371688)
So NB subframes in an NA are kosher, but the V8R subframe isn't. :(
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Originally Posted by emilio700
(Post 1371862)
I'd lean that way. More $$ but it would have better power area than a junkyard Ecotec.
The junkyard Ecotec swap could be "Spec ST4" thing, ultimate dirt cheap/go fast combo. |
Yea.
If we could get the splitter changed to 4", air dam up to 5deg and the wing raised to 8" above roofline - it WOULD be ans ST4 car! put on some 245 Hoosiers and go!
Originally Posted by jpreston
(Post 1372053)
I was just talking to Dan yesterday about how well a TSE turbo Supermiata S1 car crosses over to ST4.
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Speaking of EFR's, they just showed a smaller version at SEMA called the 5951 that is smaller in every way, yet they claim it flows 95% of a 6258. It is 35mm shorter and 35% less interia.
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Originally Posted by jpreston
(Post 1372053)
I was just talking to Dan yesterday about how well a TSE turbo Supermiata S1 car crosses over to ST4.
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