4.7 or 4.9 FD?
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From: Brownsburg, IN, United States
4.7 or 4.9 FD?
Since I will be taking the transmission apart here shortly I figured I might as well do an "upgrade" while I've got it apart.
Im going to either go with Mfactory or Pic.
What do you guys think? The car isn't driven a whole lot, but for the expo trip how is 80mph going to be with a 4.9 for 12 hours straight?
Im going to either go with Mfactory or Pic.
What do you guys think? The car isn't driven a whole lot, but for the expo trip how is 80mph going to be with a 4.9 for 12 hours straight?
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Re: 4.7 or 4.9 FD? (citrus3000psi)
http://www.specialprojectsms.c...tID=6
GEAR-X 4.928 is my recommendation.
There is not much of a difference in what I get in a tank when I had a JDM 4.7 and my GEAR-X 4.9 FD.
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Re: 4.7 or 4.9 FD? (migs)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by migs »</TD></TR><TR><TD CLASS="quote">
There is not much of a difference in what I get in a tank when I had a JDM 4.7 and my GEAR-X 4.9 FD. </TD></TR></TABLE>
How about from 4.4?
There is not much of a difference in what I get in a tank when I had a JDM 4.7 and my GEAR-X 4.9 FD. </TD></TR></TABLE>
How about from 4.4?
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Re: 4.7 or 4.9 FD? (get RIGHT)
I get 260/tank with my 4.9 all city
I get 300/tank with my 4.9 highway
My JDM 4.7 got me around 275/tank all city
Between the 2, there is a night and day difference. Just imagine going from a 4.4 to a 4.9. You will have a new found respect for your car upgrading the FD.
I get 300/tank with my 4.9 highway
My JDM 4.7 got me around 275/tank all city
Between the 2, there is a night and day difference. Just imagine going from a 4.4 to a 4.9. You will have a new found respect for your car upgrading the FD.
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Re: (migs)
so now theres three forged choices that dont need a jdm first:
PIC, Mfactory, and Gear-X
glad are finally some choices out there now for this, i plan on doing it sometime in the future.
PIC, Mfactory, and Gear-X
glad are finally some choices out there now for this, i plan on doing it sometime in the future.
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Re: (get RIGHT)
The actual difference in acceleration between the 4.4 or the 4.7 and the 4.9 is rather small. The big benefit to the shorter FD is in perceived acceleration. Because you reach redline quicker, it feels as though the car accelerates much, much faster. However, that's mostly because you reach redline at a slower speed. Your time to accelerate to that speed isn't really all that different. But the car seems quicker because you reach redline sooner.
Remember, there is better acceleration with a shorter FD, but only as long as you are in the same gear with each setup. And at other speeds, where the shorter FD forces you into a higher gear, your acceleration is slower. Here's why.
Most of our cars have a relatively flat torque curve. Acceleration is a function of torque at the wheels, which is torque at the crank times gearing (less drivetrain losses). In a nutshell - if you have shorter overall gearing, you have faster acceleration. So your point is correct, that shorter gearing means that the car accelerates faster... as long as you can remain in the same gear. However, as soon as the shorter gearing forces you to upshift, you are at a disadvantage because your overall gearing is actually longer.
For example, let's use the ITR as an example, with stock size (195/55-15) tires, taking deflection into account, assume we will accelerate to the 8400 RPM stock redline, and compare the stock gears with the stock FD (4.4) vs the ATS FD (4.928). We can calculate the total gearing (ratios of each of the regular five-speed gears times the ratio of the FD) at various road speeds. This will tell us which FD gives better acceleration, as follows:
0-35.6 mph: Stock FD first gear total gearing 14.21, ATS FD first gear total gearing 15.92, ATS is quicker (12 percent gearing advantage)
35.6-39.9 mph: Stock FD first gear total gearing 14.21, ATS FD second gear total gearing 10.37, Stock is quicker (37 percent gearing advantage)
39.9-54.7 mph: Stock FD second gear total gearing 9.26, ATS FD second gear total gearing 10.37, ATS is quicker (12 percent gearing advantage)
54.7-61.2 mph: Stock FD second gear total gearing 9.26, ATS FD third gear total gearing 7.19, Stock is quicker (29 percent gearing advantage)
61.2-78.9 mph: Stock FD third gear total gearing 6.42, ATS FD third gear total gearing 7.19, ATS is quicker (12 percent gearing advantage)
78.9-88.4 mph: Stock FD third gear total gearing 6.42, ATS FD fourth gear total gearing 5.46, Stock is quicker (18 percent gearing advantage)
88.4-104.0 mph: Stock FD fourth gear total gearing 4.87, ATS FD fourth gear total gearing 5.46, ATS is quicker (12 percent gearing advantage)
104.0-116.5 mph: Stock FD fourth gear total gearing 4.87, ATS FD fifth gear total gearing 4.18, Stock is quicker (17 percent gearing advantage)
116.5-135.7 mph: Stock FD fifth gear total gearing 3.73, ATS FD fifth gear total gearing 4.18, ATS is quicker (12 percent gearing advantage)
135.7-152.0 mph: Stock FD fifth gear total gearing 3.73, ATS FD exceeds redline, Stock is quicker
As you can see, when both FD ratios put you in the same gear with either setup, the shorter FD is faster. But at speeds where the shorter FD puts you into a higher gear, the stock FD is faster - considerably faster.
This is why the stock FD can be a big advantage on tracks where you spend a lot of time near redline, but the shorter FD can be a big advantage on tracks where you don't. So theoretically, if you were on a track where you spent the entire track driving between 79 and 88 mph, or between 88 and 104 mph, you would have a clear cut winner between the two gearing setups. However, most tracks have enough of a mix of speeds that you're probably going to be spending some time in the same gear, and some time in the higher gear, and the gains in one set of stretches will largely offset the losses in others.
Just to cite one example, in my ITR, I find that I can do a lot of Grattan in second gear - including the off-camber turn 3, the fast-turning stretch from the braking zone after the jump to turn 7, and the toilet bowl. On those stretches, a shorter FD will require the use of third gear in those turns, and possibly fourth gear elsewhere, and it would be a disadvantage in those areas. In the areas where you would be in third gear in either setup, it would be an advantage.
Incidentally, on a dragstrip, the shorter FD is more consistently an advantage, because of the large amount of time you would be in first gear, and in second gear, with either setup. In our ITR example, from 0 to 55 mph, the shorter FD is a significant advantage most of the time; however, above 55 mph (where you spend road course time) the advantage swaps back and forth between the two setups, depending on the road speed.
Remember, there is better acceleration with a shorter FD, but only as long as you are in the same gear with each setup. And at other speeds, where the shorter FD forces you into a higher gear, your acceleration is slower. Here's why.
Most of our cars have a relatively flat torque curve. Acceleration is a function of torque at the wheels, which is torque at the crank times gearing (less drivetrain losses). In a nutshell - if you have shorter overall gearing, you have faster acceleration. So your point is correct, that shorter gearing means that the car accelerates faster... as long as you can remain in the same gear. However, as soon as the shorter gearing forces you to upshift, you are at a disadvantage because your overall gearing is actually longer.
For example, let's use the ITR as an example, with stock size (195/55-15) tires, taking deflection into account, assume we will accelerate to the 8400 RPM stock redline, and compare the stock gears with the stock FD (4.4) vs the ATS FD (4.928). We can calculate the total gearing (ratios of each of the regular five-speed gears times the ratio of the FD) at various road speeds. This will tell us which FD gives better acceleration, as follows:
0-35.6 mph: Stock FD first gear total gearing 14.21, ATS FD first gear total gearing 15.92, ATS is quicker (12 percent gearing advantage)
35.6-39.9 mph: Stock FD first gear total gearing 14.21, ATS FD second gear total gearing 10.37, Stock is quicker (37 percent gearing advantage)
39.9-54.7 mph: Stock FD second gear total gearing 9.26, ATS FD second gear total gearing 10.37, ATS is quicker (12 percent gearing advantage)
54.7-61.2 mph: Stock FD second gear total gearing 9.26, ATS FD third gear total gearing 7.19, Stock is quicker (29 percent gearing advantage)
61.2-78.9 mph: Stock FD third gear total gearing 6.42, ATS FD third gear total gearing 7.19, ATS is quicker (12 percent gearing advantage)
78.9-88.4 mph: Stock FD third gear total gearing 6.42, ATS FD fourth gear total gearing 5.46, Stock is quicker (18 percent gearing advantage)
88.4-104.0 mph: Stock FD fourth gear total gearing 4.87, ATS FD fourth gear total gearing 5.46, ATS is quicker (12 percent gearing advantage)
104.0-116.5 mph: Stock FD fourth gear total gearing 4.87, ATS FD fifth gear total gearing 4.18, Stock is quicker (17 percent gearing advantage)
116.5-135.7 mph: Stock FD fifth gear total gearing 3.73, ATS FD fifth gear total gearing 4.18, ATS is quicker (12 percent gearing advantage)
135.7-152.0 mph: Stock FD fifth gear total gearing 3.73, ATS FD exceeds redline, Stock is quicker
As you can see, when both FD ratios put you in the same gear with either setup, the shorter FD is faster. But at speeds where the shorter FD puts you into a higher gear, the stock FD is faster - considerably faster.
This is why the stock FD can be a big advantage on tracks where you spend a lot of time near redline, but the shorter FD can be a big advantage on tracks where you don't. So theoretically, if you were on a track where you spent the entire track driving between 79 and 88 mph, or between 88 and 104 mph, you would have a clear cut winner between the two gearing setups. However, most tracks have enough of a mix of speeds that you're probably going to be spending some time in the same gear, and some time in the higher gear, and the gains in one set of stretches will largely offset the losses in others.
Just to cite one example, in my ITR, I find that I can do a lot of Grattan in second gear - including the off-camber turn 3, the fast-turning stretch from the braking zone after the jump to turn 7, and the toilet bowl. On those stretches, a shorter FD will require the use of third gear in those turns, and possibly fourth gear elsewhere, and it would be a disadvantage in those areas. In the areas where you would be in third gear in either setup, it would be an advantage.
Incidentally, on a dragstrip, the shorter FD is more consistently an advantage, because of the large amount of time you would be in first gear, and in second gear, with either setup. In our ITR example, from 0 to 55 mph, the shorter FD is a significant advantage most of the time; however, above 55 mph (where you spend road course time) the advantage swaps back and forth between the two setups, depending on the road speed.
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Re: (nsxtasy)
so without quoting all that...my response is: have a higher than stock redline and motor to make power at that so you can stay in gear longer with the 4.9 to match the speed the 4.4 will bring you to 
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well my 4.7 vs migs 4.9 he pulls me
its not just getting to redline faster the car is a bit quicker so it does make a differance, ecspecialy when your on a track taking tuns.
its not just getting to redline faster the car is a bit quicker so it does make a differance, ecspecialy when your on a track taking tuns.
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Re: (94rs-turbo)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 94rs-turbo »</TD></TR><TR><TD CLASS="quote">well my 4.7 vs migs 4.9 he pulls me
its not just getting to redline faster the car is a bit quicker so it does make a differance, ecspecialy when your on a track taking tuns.</TD></TR></TABLE>
At the track, it really depends on the track and the speeds where you spend most of your time. The shorter gearing can help at one track (usually, if you're in the same gears with both setups) and hurt at another (usually, if the shorter gearing forces you into a higher gear a significant part of the time).
At the dragstrip, though, the shorter gearing usually helps, unless it forces you to make an extra shift before the end of the 1/4 mile.
its not just getting to redline faster the car is a bit quicker so it does make a differance, ecspecialy when your on a track taking tuns.</TD></TR></TABLE>
At the track, it really depends on the track and the speeds where you spend most of your time. The shorter gearing can help at one track (usually, if you're in the same gears with both setups) and hurt at another (usually, if the shorter gearing forces you into a higher gear a significant part of the time).
At the dragstrip, though, the shorter gearing usually helps, unless it forces you to make an extra shift before the end of the 1/4 mile.
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Re: (Aquafina)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Aquafina »</TD></TR><TR><TD CLASS="quote">Close gear set > FD
FD doesn't give you the good RPM drop of a gear set.</TD></TR></TABLE>
Ok, Close gear sets look expensive for what I can even find on them. Anybody have some links to where there is actually information about these?
FD doesn't give you the good RPM drop of a gear set.</TD></TR></TABLE>
Ok, Close gear sets look expensive for what I can even find on them. Anybody have some links to where there is actually information about these?
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Re: (migs)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by migs »</TD></TR><TR><TD CLASS="quote">I personally suggest getting an FD over the gear set. </TD></TR></TABLE>
This is just want I need to hear. I should get my bearings in the mail early next week, so I need a fd or close gear set within a week, Not this weekeend by next weekend. I doubt I can get close gear sets that fast.
Looks like I will go with Gear Xs. And it seems to only make sense to ge with the 4.9.
</TD></TR></TABLE>This is just want I need to hear. I should get my bearings in the mail early next week, so I need a fd or close gear set within a week, Not this weekeend by next weekend. I doubt I can get close gear sets that fast.
Looks like I will go with Gear Xs. And it seems to only make sense to ge with the 4.9.
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Re: (migs)
I agreee w/ most of what you have stated, but this statement.....
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by migs »</TD></TR><TR><TD CLASS="quote">Yes, and those components are not forged. ATS 4.9 FD =
</TD></TR></TABLE>
I ran a 4.9 ats for many miles.... and, the guy I sold my car to w/ it , ran nitrous on top of it and never had any problems....
have you ever experienced any problems w/ the ats?
I am glad that there are more companies making fd's for our car, but I know a lot of people that have been running ats w/ no problems for years.....
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by migs »</TD></TR><TR><TD CLASS="quote">Yes, and those components are not forged. ATS 4.9 FD =
</TD></TR></TABLE>I ran a 4.9 ats for many miles.... and, the guy I sold my car to w/ it , ran nitrous on top of it and never had any problems....
have you ever experienced any problems w/ the ats?
I am glad that there are more companies making fd's for our car, but I know a lot of people that have been running ats w/ no problems for years.....
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Re: (migs)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by migs »</TD></TR><TR><TD CLASS="quote">I personally suggest getting an FD over the gear set. </TD></TR></TABLE>
But why?
</TD></TR></TABLE>But why?
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Re: (cmdr430)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by cmdr430 »</TD></TR><TR><TD CLASS="quote">I agreee w/ most of what you have stated, but this statement.....
I ran a 4.9 ats for many miles.... and, the guy I sold my car to w/ it , ran nitrous on top of it and never had any problems....
have you ever experienced any problems w/ the ats?
I am glad that there are more companies making fd's for our car, but I know a lot of people that have been running ats w/ no problems for years.....</TD></TR></TABLE>
Well I feel like you would be a fool if you get the ATS with a USDM tranny. With so many USDM options available.
Modified by citrus3000psi at 7:11 PM 11/21/2007
I ran a 4.9 ats for many miles.... and, the guy I sold my car to w/ it , ran nitrous on top of it and never had any problems....
have you ever experienced any problems w/ the ats?
I am glad that there are more companies making fd's for our car, but I know a lot of people that have been running ats w/ no problems for years.....</TD></TR></TABLE>
Well I feel like you would be a fool if you get the ATS with a USDM tranny. With so many USDM options available.
Modified by citrus3000psi at 7:11 PM 11/21/2007
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Re: (citrus3000psi)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by citrus3000psi »</TD></TR><TR><TD CLASS="quote">
Well I feel like you would be a fool if you get the ATS with a USDM tranny. n with so many ISDM optiions aviablable</TD></TR></TABLE>
I am not knocking the fact that there are less expensive alternatives out there.....
Just stating that the ats is a quality piece....
Well I feel like you would be a fool if you get the ATS with a USDM tranny. n with so many ISDM optiions aviablable</TD></TR></TABLE>
I am not knocking the fact that there are less expensive alternatives out there.....
Just stating that the ats is a quality piece....
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Re: (migs)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by migs »</TD></TR><TR><TD CLASS="quote">
Cost.</TD></TR></TABLE>
No other reason?
What if cost wasn't an issue?
Cost.</TD></TR></TABLE>
No other reason?
What if cost wasn't an issue?
Re: (get RIGHT)
With the gear set, you can get 3/4 or 3/4/5.
From the prices on the MFactory website:
3/4 625
3/4/5 799
FD 549
3 = 1.695
4 = 1.296 or 1.384
5 = 1.000 or 1.130
Gear set vs 4.9FD
http://www.fatboyraceworks.com...are=1
You can clearly see the gear set will be faster acceleration wise.
The RPM drop will also be significantly better.
Stock ITR,ITR 4.9-----------gear set (RPM drops to/ actual RPM drop)
1st to 2nd 5300/2700-------------5300/2700
2nd to 3rd 5600/2400------------6400/1600
3rd to 4th 6050/1950-------------6150/1850
4th to 5th 6150/1850-------------6150/1850
Not a ITR trans, but I've played around with a lot of gearing in my D trans.
Went from stock 3.7 FD to 4.71, stock long gears to hyrbid Y7/ZC gears, stock EX with 4.71 FD to EX w/ gear set and 4.25 FD blah blah blah. If I had to do it all over knowing what I know now, I would have just gone with the close gear set from the start.
P.S. Expo discount applies (3 week left until it expires).
From the prices on the MFactory website:
3/4 625
3/4/5 799
FD 549
3 = 1.695
4 = 1.296 or 1.384
5 = 1.000 or 1.130
Gear set vs 4.9FD
http://www.fatboyraceworks.com...are=1
You can clearly see the gear set will be faster acceleration wise.
The RPM drop will also be significantly better.
Stock ITR,ITR 4.9-----------gear set (RPM drops to/ actual RPM drop)
1st to 2nd 5300/2700-------------5300/2700
2nd to 3rd 5600/2400------------6400/1600
3rd to 4th 6050/1950-------------6150/1850
4th to 5th 6150/1850-------------6150/1850
Not a ITR trans, but I've played around with a lot of gearing in my D trans.
Went from stock 3.7 FD to 4.71, stock long gears to hyrbid Y7/ZC gears, stock EX with 4.71 FD to EX w/ gear set and 4.25 FD blah blah blah. If I had to do it all over knowing what I know now, I would have just gone with the close gear set from the start.
P.S. Expo discount applies (3 week left until it expires).