check this out

get over there and give em a bad time


http://forums.improvedtouring.com/it/Forum...TML/000477.html

[lateapex911]

Well, well, well.

No surprise there. I was actually guessing that the front CRXs were putting down about 124 at the wheels legally, and who knows what for the others.

A very simple equation then, as from what I understand, 12a's put out about the same. At higher revs, and with less throttle response, probably, but very close to the same WHP.

So, the CRXs weigh a lot less, run on the same size rims, and don't have a 200+ lb. axle flopping around in the back. Rusults? Better accelaration, better handling, and better braking. Win-win-win. Ugh.

Is it any wonder they are often faster? Mathmatically, it's like shooting fish in a bucket for them.

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Jake Gulick
CarriageHouse Motorsports
ITA 57 RX-7
New England Region
[email protected]

had mine dyno tuned a few weeks back, 117 SAE,I had tuned it myself and it purred like a kitten but it dynoed 108, eric, the tuner a 7's only got it to 117 but it runs like crap at 1200 to 4000 rpm then hits like a two stroke. its gonna be hard to convince some competitors its not a E/PROD motor, till they fly by me in their CRX's that is.

[ITSRX7]

Given that info, what do you think a full-bore IT-spec 1.6 can put to the ground?

AB

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Andy Bettencourt
06 ITS RX-7
FlatOut Motorsports
New England Region
www.flatout-motorsports.com

[Paul]

So what do y'all think our 12a engines would do if "they" let us match ports like everyone else?

Paul

[RobMac]

Well Yaw has some how legaly made 150hp but who knows how long he had to tune that for. http://personal.riverusers.com/~yawpower/carbcom.gif

[Dave Damouth]

I'm on record for 116 SAE, with smoothing function all the way up on a Dynojet. If you turn the smoothing off and settle for the highest peaks, you could try to claim 120, but its not real. Same with calculating it as Standard hp, the numbers will jump way up if you need to feel better.

The numbers on Yaw's site came from Mazdatrix, taken on an engine dyno. Most people see in the range of 140-145 on an engine dyno for a really well tuned motor, so 150 isn't unreasonable. Engine dyno's seem to very quite a bit from shop to shop also.

the big problem is drivetrain loss. It appears that 140-145 on an engine dyno translates into the normal 115-120 rwhp on a dynojet, a 25 hp drivetrain and accessory loss.

Many of the faster civics are claiming 130-135 rwhp, with only 145-150 on an engine dyno for a 15 hp loss.

The civic dyno graph sounds like its at the low end of the spectrum compared to some of the front running motors.

I don't think port matching will help, unless it extends into the intake or exhaust openings. Would probably hurt to port match the intake, as it has a useful anti-reversion effect.

Aero drag is probably a more telling difference between RX7 and civic. My car flattens out at an actual 105mph before the end of the straight. I'll bet the civic with the same hp flattens out at 108-110 mph.

Hi Dave, I was amazed with the on track gains that 7's only got me on the top speed end, car would hit a brick wall at 6700 in 5th with 4:88's before, now it pulls to 7400, not sure what that equates to in MPH. But I do know that 7800 in 4th is 111.06, which I bested on a lap by lap basis at my last race by 500 RPM.

[Dave Damouth]

How's it going Daryl?

In order for the mph to be 111.6 at 7800 rpm, you'd need a tire with a rolling circumference of 73.7". Don't think anyone is making one that big, unless you switched to 14 inch tires while no one was watching.

The published diameter and circumference from hoosier and others is normally for a unloaded tire. The numbers are actually lower than that. If you graph rpm vs speed from your dyno runs, it will give you a fairly accurate measure of the rolling circumference on your tires. I usually get 62.7-62.9 for 45 series, around 67.2 for 50 series hoosiers. The tires do grow a bit more on track, I calculate mph for the 45 series based on 63" rolling circumference.
If you pull a baseline run in 5th it lets you verify which 5th gear you have in your trans also, there are several different ones.

Did you get the run file from the dyno shop?

Originally posted by 7'sRracing:
Hi Dave, I was amazed with the on track gains that 7's only got me on the top speed end, car would hit a brick wall at 6700 in 5th with 4:88's before, now it pulls to 7400, not sure what that equates to in MPH. But I do know that 7800 in 4th is 111.06, which I bested on a lap by lap basis at my last race by 500 RPM.

[oanglade]

Cool!
I've been asking myself that question about the ITA CRX power.

No reason an ITA Miata can't put as much or more power to the wheels judging from the dyno runs that I have seen on 1.6 Spec Miatas.

Dave, its going great, just had the time of my life at laguna last weekend. I just assumed the 111 mph on the top of the chart was 4th but I never asked what gear it was, ill have to inquire as to what that is.

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Daryl Brightwell
ITA RX7 #11
NORPAC
ITA RX7 #77
SOPAC