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Scca Gt2 Hp ?

Old 07-30-2018, 10:28 PM
  #21  
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Originally Posted by mp4659 View Post
Gt2 is more similar to st2 then t-1 is to st2. Gt2 is less aero but more hp then st2, so a little less wing/splitter and then swap tunes and I really think car could be competitive in both classes
Just seems like you are going to have to shed HP for NASA and then your missing the aero with the SCCA trim. (But hey.... your too fast now anyway so go for it).
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Old 07-30-2018, 10:43 PM
  #22  
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Originally Posted by RX7 KLR View Post
The dominate car has been a C6 at 3130lbs with a 75mm plate (these are 2017 specs, pretty sure it only had to weigh 3030lbs in 2016).

My guess is he’s using a “built” L76 with a 75mm flat plate restrictor (3000 lbs.) with ported heads (+30 lbs.) and slick tires (+100lbs.) to get to 3130 lbs. He has a lot more going on there than just the “right”’engine for the class.

Last edited by clubracer23; 07-30-2018 at 10:49 PM.
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Old 07-31-2018, 11:57 AM
  #23  
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Randy Kinsland has won a slew of very competitive SE Div SCCA Majors and Trans Am 3 races as well in his ex Bob Mayer/Scotty B White Corvette. He has been very successful with both LS6 and LS2.
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Old 07-31-2018, 03:13 PM
  #24  
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Originally Posted by mp4659 View Post
im not really sure how that acp wing is gt2 legal but im not complaining....from what i could tell max wing length is 68'' and 10.75 cord, with a footnote allowing the apr gtc500.
This car is for sure legal. It runs under the GT2/ST rules which are in Appendix K. 72" width 12" cord

Last edited by HULLY; 07-31-2018 at 03:14 PM.
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Old 08-02-2018, 03:05 PM
  #25  
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Originally Posted by clubracer23 View Post


My guess is he’s using a “built” L76 with a 75mm flat plate restrictor (3000 lbs.) with ported heads (+30 lbs.) and slick tires (+100lbs.) to get to 3130 lbs. He has a lot more going on there than just the “right”’engine for the class.
The extra 100 pounds is for the sequential transmission.
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Old 08-02-2018, 03:13 PM
  #26  
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Originally Posted by mp4659 View Post
A built ls7 could do 500-550 through a 65mm sir. My ls7 (rip) was stock other then headers and heads done (stock cam, intake, throttle body etc) made 470whp. We detuned it to 400whp for Nasa st2. I would like to build an all forged ls3 this go round.
The rule is 3200 pounds for a built LS7 with a 65mm flat plate restrictor, not a 65mm SIR. Notice what AA is running!
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Old 08-02-2018, 07:44 PM
  #27  
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Originally Posted by DJFIN View Post
The rule is 3200 pounds for a built LS7 with a 65mm flat plate restrictor, not a 65mm SIR. Notice what AA is running!
65mm flat plate restrictor an ls7 can still make relatively big power. I cant afford a sequential so I am leaning towards an ls7 build salvaging the top end of my old motor.
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Old 08-07-2018, 03:46 PM
  #28  
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Originally Posted by mp4659 View Post
65mm flat plate restrictor an ls7 can still make relatively big power. I cant afford a sequential so I am leaning towards an ls7 build salvaging the top end of my old motor.
I'm in no way telling you what to do, just clarifying the rules. The extra 250 pounds is about 8% more weight, so you will have to make about 40 more hp then a built LS2 so around 515 hp to be even. Don't know if you can achieve that thru a 65 mm flat plate restrictor or not. I can't afford the $30K sequential trans either so I have a Rockland Gear close ratio "Transzilla" in my car. Also trying to point out that an LS3 isn't a good option per current rules. I have spoken to SCCA about this as well. Seams to me they are favoring the LS2 which GM has obsoleted, very odd.
Good luck either way.
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Old 08-07-2018, 04:03 PM
  #29  
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Originally Posted by DJFIN View Post
I'm in no way telling you what to do, just clarifying the rules. The extra 250 pounds is about 8% more weight, so you will have to make about 40 more hp then a built LS2 so around 515 hp to be even. Don't know if you can achieve that thru a 65 mm flat plate restrictor or not. I can't afford the $30K sequential trans either so I have a Rockland Gear close ratio "Transzilla" in my car. Also trying to point out that an LS3 isn't a good option per current rules. I have spoken to SCCA about this as well. Seams to me they are favoring the LS2 which GM has obsoleted, very odd.
Good luck either way.
Robert Finlayson
had a long talk with my engine builder and he agrees with you 100% , I was wrong! Looks like I’ll be building an ls2
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Old 08-07-2018, 04:29 PM
  #30  
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Originally Posted by mp4659 View Post


had a long talk with my engine builder and he agrees with you 100% , I was wrong! Looks like I’ll be building an ls2
Why no love for the L76 that is the same weight and restrictor as the LS2? It's a LS2 block with LS3 heads and intake.
The rules are very convoluted but with the way they are written I like either the "built" LS6 option (unrestricted) or "built" L76 with 75mm flat plate restrictor.
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Old 08-07-2018, 05:36 PM
  #31  
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Originally Posted by clubracer23 View Post
Why no love for the L76 that is the same weight and restrictor as the LS2? It's a LS2 block with LS3 heads and intake.
The rules are very convoluted but with the way they are written I like either the "built" LS6 option (unrestricted) or "built" L76 with 75mm flat plate restrictor.
If you think you will ever race in Trans Am3 the L76 is not a listed engine. You could probably get a waiver but im sure it would cost a weight or restrictor penalty.
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Old 08-07-2018, 06:14 PM
  #32  
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Originally Posted by HULLY View Post
If you think you will ever race in Trans Am3 the L76 is not a listed engine. You could probably get a waiver but im sure it would cost a weight or restrictor penalty.
Thanks! I know nothing about and have no plans to race Trans Am3 but now I understand why no-one is talking about the L76 engine but me!

Last edited by clubracer23; 08-07-2018 at 06:14 PM.
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Old 08-08-2018, 03:26 PM
  #33  
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Originally Posted by clubracer23 View Post
Thanks! I know nothing about and have no plans to race Trans Am3 but now I understand why no-one is talking about the L76 engine but me!
Building your car with an eye to be able to run in TA3 would be a prudent move - more racing opportunities!
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Old 09-12-2018, 11:10 PM
  #34  
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Originally Posted by Captain Buddha View Post
Building your car with an eye to be able to run in TA3 would be a prudent move - more racing opportunities!
Is there an un-published alternate spec out there for the SCCA GT2 engine/car like World Challenge or something? I swear I saw a GT2 C6 Corvette earlier this year with a FAST intake manifold on it (@3130 lbs.) and I can’t find that allowance anywhere in the SCCA GCR.

Last edited by clubracer23; 09-12-2018 at 11:13 PM.
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Old 09-13-2018, 04:04 PM
  #35  
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Originally Posted by clubracer23 View Post


Is there an un-published alternate spec out there for the SCCA GT2 engine/car like World Challenge or something? I swear I saw a GT2 C6 Corvette earlier this year with a FAST intake manifold on it (@3130 lbs.) and I can’t find that allowance anywhere in the SCCA GCR.
I have seen that car as well. It is black and has FAST on the side. I don't know if he has a FAST intake on the car or not. If he does, it isn't legal for SCCA GT2.
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Old 09-13-2018, 05:20 PM
  #36  
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Originally Posted by DJFIN View Post
I have seen that car as well. It is black and has FAST on the side. I don't know if he has a FAST intake on the car or not. If he does, it isn't legal for SCCA GT2.
Often a car is classed and runs fine even if illegal if it is not protested or on the podium. The most likely challenge would come at a serious Runoffs even where the scruts pick from a menu of things they want to check the cars in your class for.
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Old 11-07-2018, 02:40 PM
  #37  
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Originally Posted by DJFIN View Post
I'm in no way telling you what to do, just clarifying the rules. The extra 250 pounds is about 8% more weight, so you will have to make about 40 more hp then a built LS2 so around 515 hp to be even. Don't know if you can achieve that thru a 65 mm flat plate restrictor or not. I can't afford the $30K sequential trans either so I have a Rockland Gear close ratio "Transzilla" in my car. Also trying to point out that an LS3 isn't a good option per current rules. I have spoken to SCCA about this as well. Seams to me they are favoring the LS2 which GM has obsoleted, very odd.
Good luck either way.
Robert Finlayson
What do you think of the option of going with the stock LS7, with no restrictor?
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Old 11-10-2018, 06:15 PM
  #38  
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I know I'm pretty late to the conversation, but I run a OEM LS7 at 3325lbs. Remember the weights listed in the GCR are with driver. Andrew put his car on a serious diet to get down to the GCR weight, and many lightweight body panels are very expensive. It's hard to justify spending extra money to build a LS7 and restrict it and save 125 lbs. The 1st thing I'd do is a realistic assessment of how low you can get your car weight with driver and go from there. My car is competitive in most Major events. I've run OEM LS3's and built LS3's, but the LS7 really seems to pull harder and raps quicker. It makes a hell of a race car.
Mike McGinley
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Old 11-12-2018, 10:01 AM
  #39  
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Thanks Mike! It is hard for us to go below 3325 lbs. with the driver, so the option of the stock LS7 with no restrictor is our best alternative. We'll see how many more hp it can make with programming and exhaust. It seems that many of the top GT2s are getting 600 hp+ from tuned LS3 or some other combination...
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Old 11-12-2018, 12:43 PM
  #40  
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Originally Posted by jvento View Post
Thanks Mike! It is hard for us to go below 3325 lbs. with the driver, so the option of the stock LS7 with no restrictor is our best alternative. We'll see how many more hp it can make with programming and exhaust. It seems that many of the top GT2s are getting 600 hp+ from tuned LS3 or some other combination...

I wish I was even remotely close to that. My GT2 Corvette with LS2 block/LS3 heads dynos at 480 RWHP before the 75 mm restrictor. I am assuming it is around 440 RWHP with the restrictor, but I have not dyno'd it that way.
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