I topped out on 140?

[neo_]

Well I toped out my car at 140, it wouldn't pull any higher for some reason. So my question is why. As I learned our cars don't have a speed limiter. Well I am runing a chipped (Crome Pro) P28 ECU. Will that have any affects on it?

Here are my engine specs btw:

Head:
Ferrea Valve Springs
Ferrea Retainers
Skunk 2 Adjustable Cam Gears
Buddy Club Spec 4 Cams
RC 370cc Injectors

Block:
Oversized CTR Pistons 81.25mm - Yielding 12.5:1 Compression
ARP Rod Bolts
ARP Head Studs
Toda Timing Belt
ACT Clutch
TODA 10lb Flywheel


Exhaust:
Header-Tech Header (3” Collector)
Test Pipe


Misc:
Moroso Breather Kit/ Moroso Oil Catch Can
AEM Cold Air Intake with Bypass valve






Thanks

[Bbasso]

Sounds like it's limited by a high FD... But I asked him and he says stock tranny.

By chance do you have a JDM tranny in the car?

[silver]

or possibly driving up hill in a headwind? what size wheels as well?

[George Knighton]

Well I toped out my car at 140, ....Well I am runing a chipped (Crome Pro) P28 ECU. Will that have any affects on it?

It would affect it if the altered programme included a speed limiter.

Out of the box, an ITR will (eventually) redline in fifth gear. Most tracks don't give you enough room to do that, and the best driver I know only hits 145 in an ITR at Summit Point.

But...the cars will redline in fifth if you have enough room.

[Chris N]

On a track?

Kinda fast for a public road.

chris - who has never gone faster than 110 in his own car on a highway, and only a few short bursts in the middle of TN and SC.

[Dave_B]

I have done 135 on the road before, it was empty and on a toll road 2 weeks after I got my car. That was the one and only time I did that. I usually don't go any faster than 100-110 on the way to the beach. I wouldn't recommend doing that again as I know I won't. Our cars over about 80ish in an accident don't do so well.

[Chris F]

But...the cars will redline in fifth if you have enough room.

No, it absolutely wouldn't. That would be like 165 MPH...

Given enough room and a strong tailwind, then yes.

Did I quote you slightly out of context, or misunderstand you? Our cars top-speeds (Stock) are aero limited, not gearing limited.

-Chris

[Chris F]

Well I toped out my car at 140

Don't drive 140 on public roads and take pictures of the speedo at the same time! That's dangerous!

[George Knighton]

[
No, it absolutely wouldn't.

The cars will redline in fifth if you have enough room. You won't be able to do it on a typical track, which won't have a straight long enough.

We've talked about this many times in the days gone by.

[Chris F]

[
No, it absolutely wouldn't.

The cars will redline in fifth if you have enough room. You won't be able to do it on a typical track, which won't have a straight long enough.

We've talked about this many times in the days gone by.

So, if you start adding gearing, where WOULD it top out? 170? 180? 200?

And, if it's not aerodynamically limited, why is there a "top speed" listed at 143?

(I'm just about done, I don't think either of us will win... unless you can point me to a couple people that HAVE hit the redline in 5th)

[Dave_B]

Anyone near the salt flats willing to try this out? Vid with spedo or rather a radar detector, GPS or something?

[George Knighton]

[
(I'm just about done, I don't think either of us will win... unless you can point me to a couple people that HAVE hit the redline in 5th)

Win? It's not an argument.

I am one person who has done it. You're on your own searching to find the others.

My own own event was celebrated for a time, years ago, because I got away from the pace car, a Vicky that chipped out too soon.

[Bbasso]

Well I toped out my car at 140

Don't drive 140 on public roads and take pictures of the speedo at the same time! That's dangerous!

Why not???

http://memimage.cardomain.net/member_im ... 6_full.jpg


I would never do such a thing...

How about we get back on topic?

DO you think it is limited by the ECU, gearing or some really strong heads winds

[knowledge]

I have bounced off the rev limiter in 5th gear going across the Mojave desert b4 @ 3:30am. No one else around and all by myself. I will never do this again, because the tunnel vision was really set in! The speedo was pegged just past the 150MPH mark @ about 7900rpm's. Like I said the tunnel vision was really set in!

Yes the chipped ECU might be limiting you at the extreme top end of your RPM range.

*never liked chipped ECU's*

[R1366]

I would say it's the ECU.

Stock R or even just w/ I/H/E will hit 150+/-

[BudMan]

fwiw - during personal testing (yes - deserted highway so I was the ONLY 1 at risk) the car will peg the speedo @ 150. Is that off a bit...probably so. However, 140 is being stopped by the ecu in my opinion.

Now, please don't do this unless you are on safe, deserted road...hit it & get slowed back down. There's no need to lose one of our own due to silliness like taking a stupid picture while driving = DUMB! Did you think we would call you a liar for not going fast enough???

[neo_]

Well I toped out my car at 140

Don't drive 140 on public roads and take pictures of the speedo at the same time! That's dangerous!

Well the road was deserted, and a passenger took the pic.

Now thinking about it, would a 200 lb passenger cause this?

I was sitting on 140 for about 5 secs and it let off as it wouldn't go higher.

Sounds like it's limited by a high FD... But I asked him and he says stock tranny.

By chance do you have a JDM tranny in the car?

Nope, original tranny.

or possibly driving up hill in a headwind? what size wheels as well?

Wind wasn't that strong, just an average day on a flat surface. Stock wheels.

[Bbasso]

Nope, it would just take longer

[Chris N]

But...the cars will redline in fifth if you have enough room.

No, it absolutely wouldn't. That would be like 165 MPH...

Given enough room and a strong tailwind, then yes.

Did I quote you slightly out of context, or misunderstand you? Our cars top-speeds (Stock) are aero limited, not gearing limited.

-Chris

stock gearing, stock redline, stock final drive... 165mph? Are you sure? I've never herad this, ever.

[Bbasso]

Next time I'm at P1Auto, I'll ask Jack to do a fith gear red line in my car...
I'm not sure if he or the machince will let it, but I'll ask.

[George Knighton]

stock gearing, stock redline, stock final drive... 165mph? Are you sure? I've never herad this, ever.

You are right. Not that anybody's listening to me.

[Chris N]

Using this data:

Tire Diameter 23.44 inch [((195mm * (.55 x 2)) / 25.4) + 15inch]
Final Drive Ratio 4.4
1st Gear 3.23
2nd Gear 2.105
3rd Gear 1.458
4th Gear 1.107
5th Gear 0.848

You get, for 5th gear:
8000 150.4
8100 152.2
8200 154.1
8300 156.0
8400 157.9

from the spreadsheet in this thread on HAN:
http://www.honda-acura.net/forums/showt ... p?t=125485

now. Looking at the ITRCA FAQ, im not sure how the hell they got those figures for mph AND notice that it shows 8000rpm in 5th gear NOT 8400rpm like the other gears. Something is definitely not right, because the spread sheet i used indicates:
1st 8400 41.5
2nd 8400 63.6
3rd 8400 91.8
4th 8400 120.9
5th 8000 150.4
5th 8400 157.9

ITRCA FAQ says:
1st 3.230 / (8400 rpm) 39 mph
2nd 2.105 / (8400 rpm) 60 mph
3rd 1.458 / (8400 rpm) 87 mph
4th 1.107 / (8400 rpm) 115 mph
5th 0.848 / (8000 rpm) 143 mph

I checked a few formulas via google and came up with this one:
(RPM x Tire Diameter) / (FD x Gear Ratio x 336)

the spreadsheet uses
(RPM x Tire Diameter x Pi) / (FD x Gear Ratio x 1050)

Seems like some bad approximations are taking place
336 x pi != 1050 / Pi
But lets just use both for a moment.
I'm not going to go delve into where 336 or 1050/pi came from, suffice to say they come out at 157.0 and 157.9mph. Close enough.

Where did 165mph come from? And can anyone prove our cars are drag limited? And did anyone take into consideration that our speedos are off by a factor of 3% (+ or - i'm not sure! lol) ? 3% with an indicated speed of 150mph is +/- 4.5mph.

Chris - off to remember where the 336 and 1050/pi crap came from and what is the CORRECT value to use....

[Dave_B]

So that's where the 159 that I always thought it was came from. I didn't want to post it earlier as I wasn't sure if it was a whim, though I thought I read somewhere different. Thanks for that info chris.

[Bbasso]

I suck at math.

But if the # are right...
My speedo in the pic above and 8000=150.4
( I had 195/55-15s at the time)
the stock speedo is not that far off...

Very interesting!

[Chris N]

So that's where the 159 that I always thought it was came from. I didn't want to post it earlier as I wasn't sure if it was a whim, though I thought I read somewhere different. Thanks for that info chris.

well, technically its 157.01-ish MPH.

I checked around, because I could not remember where 336 came from. It's obviously a constant, and I have no idea why the other gear calc uses pi on top and 1050 on bottom, because its not even right. I don't know WHY 336 is the constant, but it is.

Well, now I do. K: ()!!y the tall 455 honkay sez you must BALANCE units. Duhhhh.
5280 = feet in a mile
12 = inches per foot
60 = minutes per hour
5280 x 12 / 60 = 1056, 1056/pi = 336.1xxxx
or 1056 on top and pi on bottom of equation. easier to just use 336.

So, knowing that, our max ACTUAL (not indicated) MPH in ideal conditions (ASSUMING WE ARE NOT DRAG LIMITED) at 8400rpm in 5th gear is just about 157mph.

Indicated/speedo speed? NO idea. Does the speedo read high or low? :shrug:

I don't know if the ITR or other Integras are drag limited. I'd guess the wing helps stability but does introduce a bit of drag, probably necessary to keep the car down. But now I'm talking way out of my league so i'll shut up.