jdm itr 98spec motor. which is better for drag racing (track of course)? 4.4 or 4.7?

 

I would assume the 4.7 would be better because you will stay into the vtec through every gear.

 

anybody know in which gear they finish the 1/4 with a 4.4 and a 4.7?

 

have you seen this post, maybe it has answer's for you?

https://honda-tech.com/zerothread?id=635736

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by KockAsian &raquo;</TD></TR><TR><TD CLASS="quote">anybody know in which gear they finish the 1/4 with a 4.4 and a 4.7? </TD></TR></TABLE>

There are alot of factors including WHP, tire size, and of course weight of the car, IE a lighter car, say 1700 crx will be in 5th, a 3000lb Integra (with stereo) and a shitty driver might end in 3rd.

Here is a gearing calculator, learn to use it.


http://www.autocrossing.com/cgi-bin/gearcalc.cgi

Mattj

 

https://honda-tech.com/zerothread?id=1105443

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by spids5 &raquo;</TD></TR><TR><TD CLASS="quote">I would assume the 4.7 would be better because you will stay into the vtec through every gear.</TD></TR></TABLE>

Wrong. Changing the final drive gear has no effect on the revs after each of your upshifts. The road speed is lower, but the engine revs are the same.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by nsxtasy &raquo;</TD></TR><TR><TD CLASS="quote">

Wrong. Changing the final drive gear has no effect on the revs after each of your upshifts. The road speed is lower, but the engine revs are the same.
</TD></TR></TABLE>

Are you sure? When I installed one in my si I was always in the vtec if I shifted around 8500 rpms but when it had a 4.4 it would barely fall out. Also my dad was the one who said I should get it for that reason and he has been a mechanic for 30 years and has raced everything from Sprint car to dragsters.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by spids5 &raquo;</TD></TR><TR><TD CLASS="quote">

Are you sure? When I installed one in my si I was always in the vtec if I shifted around 8500 rpms but when it had a 4.4 it would barely fall out. Also my dad was the one who said I should get it for that reason and he has been a mechanic for 30 years and has raced everything from Sprint car to dragsters.</TD></TR></TABLE>

nsxtasy is right...the only way you could change the amount that the revs drop is if you changed the gear ratio, not the final drive

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by spids5 &raquo;</TD></TR><TR><TD CLASS="quote">Are you sure?</TD></TR></TABLE>

Yes.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by spids5 &raquo;</TD></TR><TR><TD CLASS="quote">When I installed one in my si I was always in the vtec if I shifted around 8500 rpms but when it had a 4.4 it would barely fall out.</TD></TR></TABLE>

If you upshifted at 8500 RPM before changing the FD and the revs fell to, say, 4567 RPM, then changed the FD, that same upshift at 8500 RPM would fall to exactly the same revs (4567) as it did for the other FD.

The revs before and after upshifting are proportional to the gear ratios of the individual gears being shifted. For example, if you upshift from 8500 RPM in first gear to 4567 RPM in second gear, then the gear ratio for second gear is 4567 / 8500 = .5373 times the gear ratio for first gear. And that's true no matter what the ratio of the final drive gear is.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by spids5 &raquo;</TD></TR><TR><TD CLASS="quote">Also my dad was the one who said I should get it for that reason and he has been a mechanic for 30 years and has raced everything from Sprint car to dragsters.</TD></TR></TABLE>

Print out this topic and show it to your dad, and I think he will tell you that you misunderstood what he said...

 

Thanks for the info, I will see what he says.

 

Can I assume we are talking early vs late model ITR transmission here? If so, people make ALOT more out of the whole FD thing than it really is. The fact is that a lower FD makes a car accelerate faster than a higher FD only if the actual gear ratios are exactly the same. And this is not necessarily the case. I don't know all the gear ratios in the various ITR transmissions. But I do know that fifth gear in the early transmission (4.4 FD) is the same as a B16A transmission: .848:1. On the later transmission (4.7FD), the fifth gear ratio is the same as the GSR: .787:1. Guess what happens when you work it all out? The overall ratio is 3.73:1 for the early transmission and 3.69:1 for the later transmission! In other words, revs in fifth gear are actually LOWER in the later, 4.7FD transmission. Now it is possible that some of the lower gear ratios are such that you get BETTER acceleration in those gears with the 4.7FD transmission. But if this is so, then the overall ratios are actually WIDER with this transmission, making it EASIER to fall out of VTEC when shifting.

 

in a j4d lsd 96-97 jdm 97-98/00-01 usdm itr (4.4 fd) it finishes the 1/4 in 4th gear

p.s final drive(ring gear) is the final mutiplication of torque; that means it does affect the revolution drop/gain

 

you will do well to install a ATS 3.077 (countershaft) 1st gear along with the 4.785 FD and yes, it is better for drag. you will pull even harder if you use this first gear along with the GSR 2nd gear set. 3.23 with the 4.785 will spin hard. 3.23 to 2.104 is kinda short with that FD. 3.077 to 1.90 is better with that FD or even the ATS 4.93 to get you moving, while keeping the 1.458, 1.105, .848 intact to insure best top end acceleration while eliminating some wheel spin.

 

WHY would the GSR 2nd gear be good??? it's long as **** and mine with the 4.4 and 9K redline goes to 80. The thing I've always heard is to get a straight up up JDM ITR trans. Cause the first three gears are the same and match the way the B18C torque curve goes. I know from dyno tuning my car and ITR B18C5's that the motor LOVES to go into VTEC at 5600ish RPM and have the meat of the torque curve (close to stock cams) from 4200-5600 and engaging VTEC any sooned does no good. SO if you put in the crappy GSR 2nd gear such as I have It will almost ALWAYS fall out of VTEC unless you shift after going ALL the way to 9K. the ITR gearbox is matched for the torque curve and graph and WHY the B18C5 was geared that way. Look at a dyno chart I would post mine but and others but it was saved on Payn Tech's laptop which was stolen with everything else . Secondly the JDM ITR trans has a longer fouth and fifth gear so that A: modified examples don't shif into fifth on road course and B: so that highway mileage is conservatively better (odd that in japan freeway's are limited to 90kph I believe.

In short. JDM ITR gearset including 4.785 FD =

GSR 2nd gear + ITR trans + USDM 4th and 5th = ****

USDM and JDM ITR 1-3 = 3.230, 2.105, 1.458
JDM ITR 4-5 = 1.034, .787
USDM ITR 4-5= 1.107, .848
USDM GSR 1-3 = 3.230, 1.900, 1.360

SOOO in conclusion.

USDM GSR 2-3 BLOWS *** and JDM ITR trans for all motor apps =

Here's a link to calc all the drive ratio's as well as FD

http://www.autocrossing.com/cgi-bin/gearcalc.cgi

Toy around with it and see what you want and what best suits your app.

Think of your final mods BEFORE you decide what trans though. Cause you might as well just buy the LS trans if you are going to go turbo which is best for drag racing anyways.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by nsxtasy &raquo;</TD></TR><TR><TD CLASS="quote">

Wrong. Changing the final drive gear has no effect on the revs after each of your upshifts. The road speed is lower, but the engine revs are the same.
</TD></TR></TABLE>

http://www.autocrossing.com/cgi-bin/gearcalc.cgi

Try it out and you will see that he is right.

Also though if you do the torque multiplication tables you can PROVE that the car will be faster with the 4.7 WHILE revs remain the same the amount of torque the car is producing at the wheel is actually MUCH higher at the same RPM which is the great benefit of an FD over a gearset if your gears are short enough. more torque to the wheels at the same RPM.

I do not know the EXACT torque multiplier numbers but andrew (95stealth GSR) recently did a report on the issue and was one who I got a good deal of the info from. Contact him if you got any ?'s bout the numbers and the math. Or as most of us here at H-T know his car the "CONE"


Modified by Nytemare at 8:23 AM 1/6/2005

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Humping_dragon &raquo;</TD></TR><TR><TD CLASS="quote">p.s final drive(ring gear) is the final mutiplication of torque; that means it does affect the revolution drop/gain</TD></TR></TABLE>

Wrong.

Yes, it's the final multiplication of torque. However, it multiplies the revs before the upshift, and it multiplies the revs after the upshift. So when you're comparing the two, it eliminates itself as a factor.

Do the math.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Nytemare &raquo;</TD></TR><TR><TD CLASS="quote">Also though if you do the torque multiplication tables you can PROVE that the car will be faster with the 4.7 WHILE revs remain the same the amount of torque the car is producing at the wheel is actually MUCH higher at the same RPM which is the great benefit of an FD over a gearset if your gears are short enough. more torque to the wheels at the same RPM.</TD></TR></TABLE>

That is true. But... (and there is always a "but" with gearing, because when gearing changes help in some ways, they usually hurt in others)

Yes, the shorter FD will accelerate faster in a specific gear with the engine turning a specific number of revs. No question about that.

The downsides of a shorter FD occur in two ways. One is the qualifier: the shorter FD is faster as long as you're in the same gear. For example, second gear with the shorter FD is always faster than second gear with the stock FD. However, the shorter FD lowers the road speed at which you need to shift. As a result, there are speeds for which the shorter FD will require a higher gear than the stock FD, and at those speeds, the stock FD is faster (because the overall gearing is shorter). For a detailed description of the speeds at which this occurs, comparing a 4.9 FD with the stock 4.4, read this previous post. The other downside is that top speed is lowered, because redline in top gear occurs at a lower speed. Oh, and gas mileage is worse, but nobody cares about that...

Basically, the shorter FD is usually better for drag racing, because it will improve your acceleration throughout first gear (as long as it doesn't require an additional shift during the 1/4 mile). But it's not always better for road racing, where acceleration at higher speeds (typically 60-120 mph) is not always improved overall, and can actually be worse, depending on the speeds at any particular track.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by nsxtasy &raquo;</TD></TR><TR><TD CLASS="quote">
But it's not always better for road racing, where acceleration at higher speeds (typically 60-120 mph) is not always improved overall.
</TD></TR></TABLE>

I think it's safe to say that a shorter FD is almost always faster on a road course, even at those higher speeds....at least based on my experience, and what I've read/heard/seen.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by El Pollo Diablo &raquo;</TD></TR><TR><TD CLASS="quote">I think it's safe to say that a shorter FD is almost always faster on a road course, even at those higher speeds....at least based on my experience, and what I've read/heard/seen.</TD></TR></TABLE>

Not necessarily.

For example, the stock FD is faster than the 4.928 FD at speeds of 79-88 mph and 104-116 mph, and has a bigger gearing advantage than the 4.928 FD gives you at speeds of 88-104 mph (as noted in the post from the link in my post just above yours; you can find the calculations there). So if you're on a track where you're spending most of your time between 79 and 116 mph, it's quite likely that the stock FD may actually be quicker.

Again, it depends on the particular track and the speeds involved.

Sometimes, the shorter FD gives a perception of being quicker that is not realized in actual acceleration times. That's because it reaches redline quicker than a stock FD. But it does so at a lower road speed, and when it does, you're then upshifting to a higher gear - which is where it's at a disadvantage in overall gearing. So it seems like it's quicker, even when it's not.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by StorminMatt &raquo;</TD></TR><TR><TD CLASS="quote">Can I assume we are talking early vs late model ITR transmission here? If so, people make ALOT more out of the whole FD thing than it really is. The fact is that a lower FD makes a car accelerate faster than a higher FD only if the actual gear ratios are exactly the same. And this is not necessarily the case. I don't know all the gear ratios in the various ITR transmissions. But I do know that fifth gear in the early transmission (4.4 FD) is the same as a B16A transmission: .848:1. On the later transmission (4.7FD), the fifth gear ratio is the same as the GSR: .787:1. Guess what happens when you work it all out? The overall ratio is 3.73:1 for the early transmission and 3.69:1 for the later transmission! In other words, revs in fifth gear are actually LOWER in the later, 4.7FD transmission. Now it is possible that some of the lower gear ratios are such that you get BETTER acceleration in those gears with the 4.7FD transmission. But if this is so, then the overall ratios are actually WIDER with this transmission, making it EASIER to fall out of VTEC when shifting.</TD></TR></TABLE>


You are assuming jdm itr trannies (96 spec vs 98 spec).

We are assuming usdm itr trannies (equivalent to jdm 96 spec) - since we are in the US. For the original poster, I'd recommend changing the 3,4,5 gearset to ATS in an effort to help you conquer the 1320 quicker. There is less loss of rpm on the upshift with this close ratio gearset.....

4.9 &gt; 4.7 &gt; 4.4 Assume stock usdm 1,2,3,4,5 gears.

And my final note on that is you should simply raise your redline by ~500 rpm to account for any need to upshift.....

 

so you guys are telling me that my R might be slower with the ATS 4.9 FD vs the stock 4.4 FD ?????

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by fastvtecCL &raquo;</TD></TR><TR><TD CLASS="quote">so you guys are telling me that my R might be slower with the ATS 4.9 FD vs the stock 4.4 FD ?????</TD></TR></TABLE>

At certain speeds, yes.

You obviously haven't read the previous post for which I posted the link above. Click here and read, and then we'll talk.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by fastvtecCL &raquo;</TD></TR><TR><TD CLASS="quote">so you guys are telling me that my R might be slower with the ATS 4.9 FD vs the stock 4.4 FD ?????</TD></TR></TABLE>

nsxtasy posted right above what it TRUE: "the stock FD is faster than the 4.928 FD at speeds of 79-88 mph and 104-116 mph, "

This is of course assuming stock redline. Simply raise your redline approximately ~500 rpm to get back that which is now missing. Get it?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Black R &raquo;</TD></TR><TR><TD CLASS="quote">This is of course assuming stock redline. Simply raise your redline approximately ~500 rpm to get back that which is now missing.</TD></TR></TABLE>

If you raise the redline (something I wouldn't want to risk MY engine on, but hey, that's a separate issue), and if your engine maintained its torque all the way to the higher redline (a questionable assumption for a stock engine, but let's go with it)... then that would have the same benefit with the stock FD as it would with the shorter FD. In other words, it wouldn't change any of the conclusions you would come to; they would just happen at slightly higher speeds (reflecting higher shift points).

 

I like the stocker. Once I'm in 3rd (and have traction..) I never drop out of vtec and I'm just shifting into 5th..see vid

I was hitting boost cut in this vid, but normally I would rev a bit higher in each gear and not have to shift into 5th.
http://ffdet.com/members/jan/vids/12.7run.wmv