MAZMART 13B vs 600 hp Corvette
 

This is a full race 2011 SCCA RX-7 that we build engines for. All R&D including dyno work for this car is done here at Mazmart by Rick Engman. The Corvette is making around 600 rwhp. The RX-7 driver is Jeff Dernehl of Roswell Outback Automotive in Roswell GA. He owns the car and fabricates most everything on it. He generally kicks ass and has been breaking track records throughout the US.

Enjoy!


Paul.

First thought- um Paul thats a Mustang not some Corvette(throwing in some redneckish sothern/mountain"mr ducks" kinda voice)

2nd thought- ohhh that rite cheer is a pacecar(mrducks voice again)

3rd- that fooker is louuuuuwwwwed should warnt a fella

Nice!

6:0something- dang it drive thru the dirt there it works all the time on the time on my ps3!!
8:2x- traffic is abitch

ya know hwy that corvette stayed ahead for so long? its like the fox and the rabbit. who wins the chase between the fox and the rabbit most of the time ? the rabbit because he's running for his life and the fox is just getting his lunch.

in this case that 'vette fella could hear that hornets nest chasing him the whole time and was running for his life :)

Foxes should not mess with hornets :naughty:.

Paul.

had then been "Barbers" that vette would be lunch...Road atlanta favors higher horsepower cars

Thanks for sharing Paul. That was great. Shorther track and that Vette would have been toast.

That guy drives. Flat out most of time.

Thanks E. The 7 is really well sorted down to ratios, weight distribution, aero. The full works.

Paul.

Damn, that 7 sounds good...

Fast lil bugger. Cool video!

great video, that corvette would be doomed on a short track.

Thought he had the vette at 8.18 when it got boxed in for a second - damnit . Great video all the same .

That poor Scion never saw it comin, but i'm sure he heard them!

My pants is wet
...

Great vid paul!!!



Hahaha that poor scion

Damn... Sick ass video

The way the gap closed going into the turns after that fastest straight was impressive. I'm really surprised the 7 didn't take the vette considering the fact that the advantage the vette had in the straights was almost completely gone before going into the turns.

Was the vette driver hitting the brakes too early or is that 7 just that much better?

Sorry...what ddddiiiiid you say...I can't hear you!...

I wonder if he pre-mixes..what brand....??????????
What kind of engine oil does he use..... 5W20 I bet!!!..

Sorry, I thought Id just get in first!....

WeLLLLLL??

Why do they all get a checkered flag?

Don't tell me they're all winners either..;)

Ha ha! It's all Red Line in that car. 50WT Racing oil for the engine and the pre-mix is Red line as well.

Paul.

They both won their classes. The RX-7 is SCCA GT2 I believe and he was attacking a car in a higher class. He beats higher class people regularly.

Paul.

Playing my song! Thanks for sharing.

SWEET! Nothing like light weight, an engine with a large usable rpm and world class brakes.
Rx7's after years and years--continue to embarass much more "faster" cars.

Thats the ONE thing I dont like about Road Atlanta. The back straight is nothing but a drag race. They need to shorten it about 1/8 of a mile!
Another thing --I do bet that Corvette driver was much more "tired" after the race. Those things are a beast to drive. Course the 7 guy probably couldnt hear a thing afterward!

Amazing car and amazing driver.
The difference in race lines says a lot about the different cars' capabilities.

Kick ass vid! Thanks for sharing :)

:yesnod: Especially towards the end where it looked like his tires were going. He was really sliding it trough the corners where the Rx7 looked like it was still just cruising through his line.

Laping the Lotus at least twice FTW!!

Nice vid! Anyone know what his Mazda looks like? Shit the way they were blowing by cars:crazy:. At work, cant surf too much.

Damn nice vid. I wonder how an rx8 will do with that engine.

I'll get some pics of it up later. Thanks Silver.

Paul.

Like the anime initial d saids. The guy being chase will have much much more pressure and might eventually led to mistakes. Lucky it was a quick race. Otherwise the 7would have past him. But it looked pretty bad for the vette already consider a car thats a class lower almost had him

Great F'in vid!

what is the weight difference between the two? ;)

I shall inquire sir.

Paul.

This is what it looks like.

Paul.

The Corvette is STO Class and weighs 3200 lbs. It has a built 427 engine and makes over 600 flywheel hp. The RX-7 is running GT2 spec in the video and weighs 2030 lbs which is 230 lbs under it's normal GT3 weight. It also has it's intake restrictor removed.

Paul.

Awsome! I didn't think it would have doors:rofl:

:score:

Is the Vette on slicks?

I think the term is "r-compound." So it doesn't have tread and thus looks like a "slick," but I'm betting that the tires are not at all like a 'slick' that would be selected by someone looking to drag race.

And both cars would be on r-comps. There isn't a point in door to door racing on anything less unless you aren't on dry pavement.

I wasn't referring to drag racing slicks, Captain Obvious.

He mentioned the Vette was running STO class. I'm no expert and I'm trying to learn something here, but apparently the STO class is not allowed to run racing slicks for the Runoffs where the GT3 cars can. I was wondering how much it contributes to the situation where the GT2 GT3 cars are faster in the corners, but the STO are faster on the straights.

Bob(Corvette) is on Hoosier A6's. They are an extremely sticky tire/compound, but were built for AutoX so in a 30-45 minute race they start to fall off towards the end. No idea what Jeff was on. As you said, GT classes can run a full race slick which takes a lap or two to get up to temp, but will hold it's grip much longer.

I am at work so I haven't gotten a chance to watch the video yet, but I'm looking forward to it! That RX-7 is beautiful!

1200 lb weight difference is omfg HUGE. I don't know how much power the RX-7 is making, but even moderate power levels would put it significantly past the Corvette in p/w ratio.

Bingo. That is exactly the answer to why the Corvette was "sliding through the corners" at the end. A6s are Hoosier slicks designed for short stints with minimal heat cycles. They are the tire of choice for autocross and Time Trial racing (5 laps maximum). You cannot run a full length session on A6s, they just grease up and slide all over the place.

Equal P/W (5.33lbs per HP) if the RX-7 is at 380hp (ignoring "under the curve"). Since the video clearly shows the Corvette pulling on him quite easily, I'd bet that his power level is around 300hp (6.76lbs per HP) or lower.

1200 lbs is a big freaking difference!

Oh well again if there were more corners the 7 wouldve got the vette already

That's not exactly true. You CAN run A6's in sprint races (30-45 minutes) and many of the top guys have been for many years. They do start to fall off as the race progresses, but they are still predictable and faster than an R6.

I would guess the RX-7's engine has less than 300hp. My bet would be somewhere in the 250rwhp range. That is all speculation on the engine hp though.

Regardless, incredible car and an even more incredible driver! :yesnod:

I'm not at liberty to give his figures here but we'll just say he's comfortably above your estimates :) We have done more r&d on this guy than we've done in quite some time.

Thanks for the complements; Jeff does kick ass and holds lap records at a few tracks well.

Paul.

I'll take that bet !

Paul, do you mean Bret's estimate? I'd agree that it's too low.

Mine? I could be off, but I doubt I'm all that low. At 380hp ("hp", not sure if the 600hp in the title of the vette is crank or wheel, but whichever it is, I'm using the same basis) they would have the same power to weight, and off the slow corners they would accelerate at roughly the same weight, although gearing differences could shift it around a bit. They both go through a few gears, so it's not a simple 1-gear ratio difference here.

Hmm. I know at some point, HP matters more than P/W for simple speed, as aero drag takes a larger and larger chunk of the power, dropping the effective p/w much faster for lower powered cars than higher powered (assuming the same coefficient of drag), but I'd still say that the 5.33 lbs per hp of the vette is superior to whatever the 7 has, but it's not glaringly drastic and getting 300hp out of an FD is a fairly simple matter for you, so it's AT LEAST that.

I can't see it being much above 350hp though. :dunno: Of course, the "600hp" of the vette could be a rough number too, throwing much of this out the window :lol:

To make a closer guess I'd have to compare the elapsed time between two fixed points for each of them to quantify how much the vette is stretching it's lead, and since it's a known course, we can get the measurements fairly accurately. Then the only error rate left in the calculation is the gearing differences.

i'd say 320 flywheel hp, 280ish at th wheels.
Hp\lbs aside what really matters is the chassis setup. the fd3s is just faster, softer on the kerbs and with a lot more grip available.

100% agree that it's more critical to the FD's lap times than it's power level. It's clearly faster through many parts of the course.

But the discussion turned to "how much power does the FD have", and for that, grip and chassis setup isn't a factor. I'm basing my estimates entirely on the rate at which the vette pulls away from the FD on the straights. FD enters the straights at a higher speed, but it's fairly quickly nullified by the vette's power.

the fd3s trany is probably a hewland or a holinger... ;)
even a 300hp gap can be drastically reduced with a better chassis and drivetrain! the vette barely has a chassis... the divetrain is what it is too.