C8 Corvette making potential GT500 buyers rethink their options

GTSpartan

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There is nothing unrealistic about it. Look at the 1/4mile and trap speed. Look at the potential LS based motors have in the aftermarket. Its likely closer to its 495hp rating when running at the limit.

We shall see when owners get them. The Zupra is putting down far more power than rated as well.

There is literally a 0% chance the LT2 makes anywhere near the power MT says it does. The SAE J1349 ensures that each engine is within something like 1.5-2% of the engine rating. Not +30% over the factory rating LOL!
 

blk02edge

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I guess nobody is actually reading the full article. Since when do 3600lb 440whp cars trap 123mph?
 

Double"O"

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I guess nobody is actually reading the full article. Since when do 3600lb 440whp cars trap 123mph?
My 01 Cobra has trapped 122 at full weight and 468rwhp...granted the air was perfect...she usually trapped 120-121...but one morning with the DA in the mineshaft she went 122
 

FordMoCo21

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If this car was actually making mid 600 crank hp, 121-123 mph in the quarter would be dreadful.
13/14 GT500s traps 125 with 660+ crank hp and weigh 3800lbs. That is right in line with a 3600lb, 600hp car trapping 123-124, which is what the mags are getting.
 

AustinSN

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The dyno result they end up with is 478whp... Not mid 600's crank

I kind of stopped paying attention after the first couple dyno pulls, it's obvious something funky is going on (550wtq on that 478whp pull). Not saying it doesn't make 478 wheel, that's more in line but I almost never believe a stand-alone dyno number. I'll reserve judgement until I see more.

13/14 GT500s traps 125 with 660+ crank hp and weigh 3800lbs. That is right in line with a 3600lb, 600hp car trapping 123-124, which is what the mags are getting.

If the 13/14 GT500 had that dual clutch behind it, it would probably run 130. The A10 mustang GT traps about 4-5 mph faster than the manual.

Most mags are getting 121 with the C8 (this is even the consensus on the Corvette forum), also it's what GM has stated.

Bringing up the A10 Mustang, a car that has run 119-120 with several different magazines and even faster in the hands of owners, makes about 420-430whp (the highest I found in a quick search is 437whp, and lots below 420) at 3850lbs.

So I guess I'll ask this question, if you bought this car and it only went a few mph faster than a Mustang GT in the quarter, with 140hp more and 250lbs less weight, would you think the car actually made 600hp?


I imagine more dyno numbers will start to show up relatively soon, I expect them to settle in the 460whp range, which would put it nicely in the low 500s crank.
 

FordMoCo21

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I kind of stopped paying attention after the first couple dyno pulls, it's obvious something funky is going on (550wtq on that 478whp pull). Not saying it doesn't make 478 wheel, that's more in line but I almost never believe a stand-alone dyno number. I'll reserve judgement until I see more.



If the 13/14 GT500 had that dual clutch behind it, it would probably run 130. The A10 mustang GT traps about 4-5 mph faster than the manual.

Most mags are getting 121 with the C8 (this is even the consensus on the Corvette forum), also it's what GM has stated.

Bringing up the A10 Mustang, a car that has run 119-120 with several different magazines and even faster in the hands of owners, makes about 420-430whp (the highest I found in a quick search is 437whp, and lots below 420) at 3850lbs.

So I guess I'll ask this question, if you bought this car and it only went a few mph faster than a Mustang GT in the quarter, with 140hp more and 250lbs less weight, would you think the car actually made 600hp?


I imagine more dyno numbers will start to show up relatively soon, I expect them to settle in the 460whp range, which would put it nicely in the low 500s crank.

I will agree the 18-20 A10s are an anomaly as far as trap speeds, Motor Trend stated the A10 went 3mph faster than the manual. However that is not the norm when comparing manual to automatic same model cars. The C7ZR1 manual vs auto trap very similar, and do not have this huge leap the A10 Mustangs have between transmissions. Their A10 ratio tuning really is perfect for 1/4 mile.

The 2017 Ford GT trapped 130mph per Motor Trend, with its 7 speed DCT. That car makes 590ish whp, and weighs 3350lbs, you think the 13/14 GT500 would trap almost 130 with just a DCT, but that is impossible considering the Ford GT has the same rwhp, a DCT, weighs 450lbs less and barely breaks 130mph.

If GM was able to setup the ratios in a manner similar to the A10, so that it is practically an anomaly in 1/4 mile times/traps, then I can see a minimum of 500whp. A 3600lb 500whp car will normally trap 120+/-. So if the 500whp C8 would trap 120ish with a manual, and the new trans sees the same advantage as the A10 Mustangs, gaining it 3mph over the manual, there is the 123mph MT got. So that's more like 550+ crank not 600. Still pretty drastically underrated.

I understand the new DCT could potentially see an even bigger leap than the A10 Mustang to manual comparison, however, why would the new Ford GT, which presumably has a more advanced DCT than the new C8 not trap much higher than you would expect from a manual car with similar power:weight? Your typical GT500/Coyote boosted car that weighs 3600lbs/630ishwhp traps 130, same power:weight as new Ford GT, lacking the DCT, but traps similar. I believe your A10 Mustang comparison is more of an exception to the rule, not the rule. Even the 720s traps what it should based on power to weight, they are a **** ton underrated as well, 3100lb car, 690whp, traps 141(per Motor Trend, have to keep things apples to apples here, no hero runs), right on the money for power:weight and estimating trap speeds, and no advantage for its trans? I doubt it has a lacking non-manual trans, but it doesn't trap any higher than a manual car with that numbers would... The only other car that has a crazy advantage such as the A10 Mustang, is Porsches PDKs, they trap much higher than they should. I honestly doubt the new C8 will have a trans anywhere near that.
 

FordMoCo21

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I kind of stopped paying attention after the first couple dyno pulls, it's obvious something funky is going on (550wtq on that 478whp pull). Not saying it doesn't make 478 wheel, that's more in line but I almost never believe a stand-alone dyno number. I'll reserve judgement until I see more.

Except that the 478whp pull was done with an effective gear ratio of .7 which is not the 1.0 needed for accuracy. The closer they get to 1.0 the higher the rwhp number is going. If anything the 478whp is a lot lower due to this. The torque is screwy because again the effective ratio is not 1.0, you really should finish reading the article. Also, they tested another vehicle and it was perfectly in line with power ratings, so not sure how it could be a dyno machine fault. Sounds like some GM buffoonery if anything. Underrating massively, or sending out hotter than normal cars to the press.
 

FordMoCo21

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There is literally a 0% chance the LT2 makes anywhere near the power MT says it does. The SAE J1349 ensures that each engine is within something like 1.5-2% of the engine rating. Not +30% over the factory rating LOL!
Cool, do you care to explain why Hellcats dyno, SAE, at 640+whp? You really think they only have 9% drivetrain loss, the same as a mid engined, carbon fiber wheeled 2018 Ford GT? Lmfao. No. Hellcats make 640-650whp which equates to ~750hp. Nowhere near 1-2% of 707.
 

FordMoCo21

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My 01 Cobra has trapped 122 at full weight and 468rwhp...granted the air was perfect...she usually trapped 120-121...but one morning with the DA in the mineshaft she went 122
Yeah you're going to pickup 10-20whp in amazing air. So a 3300lb-ish car with 470-480whp is going to trap 121 or so. The point some of us are trying to make is, how would a car that weighs 300lbs more than yours, and is supposed to make 20-30whp less (495 crank would be around 450whp midengined), trap 2-3mph HIGHER at 123-124 (Car and Driver/Motor Trend numbers)
 

blk02edge

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Except that the 478whp pull was done with an effective gear ratio of .7 which is not the 1.0 needed for accuracy. The closer they get to 1.0 the higher the rwhp number is going. If anything the 478whp is a lot lower due to this. The torque is screwy because again the effective ratio is not 1.0, you really should finish reading the article. Also, they tested another vehicle and it was perfectly in line with power ratings, so not sure how it could be a dyno machine fault. Sounds like some GM buffoonery if anything. Underrating massively, or sending out hotter than normal cars to the press.
Yea so I figured given the screwy ratios it would be realistically 490ish whp and 500ish wtq. Far from out of line IMO
 

AustinSN

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I will agree the 18-20 A10s are an anomaly as far as trap speeds, Motor Trend stated the A10 went 3mph faster than the manual. However that is not the norm when comparing manual to automatic same model cars. The C7ZR1 manual vs auto trap very similar, and do not have this huge leap the A10 Mustangs have between transmissions. Their A10 ratio tuning really is perfect for 1/4 mile.

The 2017 Ford GT trapped 130mph per Motor Trend, with its 7 speed DCT. That car makes 590ish whp, and weighs 3350lbs, you think the 13/14 GT500 would trap almost 130 with just a DCT, but that is impossible considering the Ford GT has the same rwhp, a DCT, weighs 450lbs less and barely breaks 130mph.

If GM was able to setup the ratios in a manner similar to the A10, so that it is practically an anomaly in 1/4 mile times/traps, then I can see a minimum of 500whp. A 3600lb 500whp car will normally trap 120+/-. So if the 500whp C8 would trap 120ish with a manual, and the new trans sees the same advantage as the A10 Mustangs, gaining it 3mph over the manual, there is the 123mph MT got. So that's more like 550+ crank not 600. Still pretty drastically underrated.

I understand the new DCT could potentially see an even bigger leap than the A10 Mustang to manual comparison, however, why would the new Ford GT, which presumably has a more advanced DCT than the new C8 not trap much higher than you would expect from a manual car with similar power:weight? Your typical GT500/Coyote boosted car that weighs 3600lbs/630ishwhp traps 130, same power:weight as new Ford GT, lacking the DCT, but traps similar. I believe your A10 Mustang comparison is more of an exception to the rule, not the rule. Even the 720s traps what it should based on power to weight, they are a **** ton underrated as well, 3100lb car, 690whp, traps 141(per Motor Trend, have to keep things apples to apples here, no hero runs), right on the money for power:weight and estimating trap speeds, and no advantage for its trans? I doubt it has a lacking non-manual trans, but it doesn't trap any higher than a manual car with that numbers would... The only other car that has a crazy advantage such as the A10 Mustang, is Porsches PDKs, they trap much higher than they should. I honestly doubt the new C8 will have a trans anywhere near that.

Except that the 478whp pull was done with an effective gear ratio of .7 which is not the 1.0 needed for accuracy. The closer they get to 1.0 the higher the rwhp number is going. If anything the 478whp is a lot lower due to this. The torque is screwy because again the effective ratio is not 1.0, you really should finish reading the article. Also, they tested another vehicle and it was perfectly in line with power ratings, so not sure how it could be a dyno machine fault. Sounds like some GM buffoonery if anything. Underrating massively, or sending out hotter than normal cars to the press.

I can already tell we aren't going to see eye to eye on this.

But lets wait for more dyno results, so we will see. I'm going to maintain this car makes around 460whp. You were saying 600 crank, but now youre down to 550+ crank, so you believe it will be 500+whp?
 

FordMoCo21

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I can already tell we aren't going to see eye to eye on this.

But lets wait for more dyno results, so we will see. I'm going to maintain this car makes around 460whp. You were saying 600 crank, but now youre down to 550+ crank, so you believe it will be 500+whp?

If the new DCT is a drag king (like the A10 in the Mustang) then I can see 490-500whp trapping 123. However I have my doubts the trans is all that, and I believe it would need 530-540whp to trap 123+ at 3600lbs.
 

AustinSN

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If the new DCT is a drag king (like the A10 in the Mustang) then I can see 490-500whp trapping 123. However I have my doubts the trans is all that, and I believe it would need 530-540whp to trap 123+ at 3600lbs.
Sounds good

530-540whp
 

ON D BIT

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Read the whole article, they give explanations given by the engineers.


Essentially, the SAE tests are far from just a simple pull, they are at the peak heat and load. When cold its way above its SAE rating.
If that were true all cars would Dabo at 100% or 110% of their crank power.

There is nothing unrealistic about it. Look at the 1/4mile and trap speed. Look at the potential LS based motors have in the aftermarket. Its likely closer to its 495hp rating when running at the limit.

We shall see when owners get them. The Zupra is putting down far more power than rated as well.
And the 460/470rwhp 3150lb c6z is trapping at 128 with a stick. Somethings off by a lot.

There is literally a 0% chance the LT2 makes anywhere near the power MT says it does. The SAE J1349 ensures that each engine is within something like 1.5-2% of the engine rating. Not +30% over the factory rating LOL!
You’re right chassis dynos have very little accuracy. Why the race teams all run engine dyno.
 

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