Si tranny with a HF final drive?
Thread Starter
Joined: May 2004
Posts: 2,053
Likes: 0
From: FUNK SQUAD, HomeSeven, america
Si tranny with a HF final drive?
like that says^^^....
Does anyone have this done? I'd love to have the acceleration of an Si tranny through 1st,2nd,3rd, and 4th, but have the highway cruising of the HF (based on http://crx.honda-perf.org/math/index.html )for better gas milage. So is this do-able and easy? I honestly have no realistic clue about all the tranny talk, mostly because i'm still learning all the engine stuff.
I searched and didn't find much but that site. So any input would be nice
Does anyone have this done? I'd love to have the acceleration of an Si tranny through 1st,2nd,3rd, and 4th, but have the highway cruising of the HF (based on http://crx.honda-perf.org/math/index.html )for better gas milage. So is this do-able and easy? I honestly have no realistic clue about all the tranny talk, mostly because i'm still learning all the engine stuff.
I searched and didn't find much but that site. So any input would be nice
Thread Starter
Joined: May 2004
Posts: 2,053
Likes: 0
From: FUNK SQUAD, HomeSeven, america
Re: Si tranny with a HF final drive? (CRX_1.8T)
i'd love to get better gas milage than i did before if at all possible, and if you are going for quickness you wouldn't even shift to 5th, so it'd be a just highway gear......just like i want
Member
Joined: May 2003
Posts: 2,157
Likes: 2
From: Saint Joseph, MO, USA
the final gear is what gives you the acceleration. you want to change out the 5th gear, not the final gear. As long as the shafts are the same size, you can swap them out. I've never taken apart an HF tranny, but i know the DX and Si have the same shafs.. i heard the HF has smaller bearings which would mean smaller shafts so the gear wouldn't work.
If you have an HF tranny, take it apart and take the 5th gear out and see if it fits in your tranny
If you have an HF tranny, take it apart and take the 5th gear out and see if it fits in your tranny
Senior Member
Joined: Jul 2003
Posts: 7,776
Likes: 0
From: Yankee in Wilmington, NC
Re: Si tranny with a HF final drive? (mr_valentino20032000)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mr_valentino20032000 »</TD></TR><TR><TD CLASS="quote">i want the "slap you back in the seat" feeling you get from the Si tranny, with only 100 HP under the hood 
</TD></TR></TABLE>
si and dx have the same gear ratios just different final drives...you need to swap just the 5th gear than for gas mileage...
</TD></TR></TABLE>si and dx have the same gear ratios just different final drives...you need to swap just the 5th gear than for gas mileage...
Trending Topics
Honda-Tech Member
Joined: Sep 2002
Posts: 227
Likes: 0
From: usa
Re: Si tranny with a HF final drive? (crxgator)
my dx gets 37mpg and my si gets 33mpg. i dont think its even worth the swap.. but if someone can come up with more info on the hf 5th lemme know. im very interested too
scott
scott
Honda-Tech Member
Joined: Mar 2004
Posts: 419
Likes: 2
From: Escondido, CA, USA
Re: (91civicDXdude)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 91civicDXdude »</TD></TR><TR><TD CLASS="quote">the final gear is what gives you the acceleration. you want to change out the 5th gear, not the final gear. As long as the shafts are the same size, you can swap them out. I've never taken apart an HF tranny, but i know the DX and Si have the same shafs.. i heard the HF has smaller bearings which would mean smaller shafts so the gear wouldn't work.
</TD></TR></TABLE>
um, the shafts are all the same I.D. you can even put cable gears into a hydro box. their height is the only difference. you just have to shim the gears to get the same install height.
</TD></TR></TABLE>
um, the shafts are all the same I.D. you can even put cable gears into a hydro box. their height is the only difference. you just have to shim the gears to get the same install height.
Thread Starter
Joined: May 2004
Posts: 2,053
Likes: 0
From: FUNK SQUAD, HomeSeven, america
Re: (91civicDXdude)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by crxgator »</TD></TR><TR><TD CLASS="quote">
si and dx have the same gear ratios just different final drives...you need to swap just the 5th gear than for gas mileage...</TD></TR></TABLE>....so it will fit>? has anyone done it?
si and dx have the same gear ratios just different final drives...you need to swap just the 5th gear than for gas mileage...</TD></TR></TABLE>....so it will fit>? has anyone done it?
Honda-Tech Member
Joined: Jul 2003
Posts: 1,264
Likes: 0
From: Central Texas
1. "Final Drive" is not the same thing as 5th.
2. You can put a HF 5th in an otherwise stock si tranny. This make your 5th gear cruise right about 400 rpms lower then before.
3. Is it worth it? Debateable. You'd have to spend a lonnnggg time in 5th to see a MPG benefit. It is a noticeably quieter at 80 mph though.
2. You can put a HF 5th in an otherwise stock si tranny. This make your 5th gear cruise right about 400 rpms lower then before.
3. Is it worth it? Debateable. You'd have to spend a lonnnggg time in 5th to see a MPG benefit. It is a noticeably quieter at 80 mph though.
Thread Starter
Joined: May 2004
Posts: 2,053
Likes: 0
From: FUNK SQUAD, HomeSeven, america
Re: (davens)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by davens »</TD></TR><TR><TD CLASS="quote">1. "Final Drive" is not the same thing as 5th.
2. You can put a HF 5th in an otherwise stock si tranny. This make your 5th gear cruise right about 400 rpms lower then before.
3. Is it worth it? Debateable. You'd have to spend a lonnnggg time in 5th to see a MPG benefit. It is a noticeably quieter at 80 mph though.</TD></TR></TABLE>
ok so you can put the 5th gear onto the Si tranny, but the final drive is a no. Ok and the reason was more like a cruisin RPMs type thing. As i remember it was like 4500 to cruise at 75, and the "final drive" on the HF was at 3200 so yeah it'd like to be able to hear better too
2. You can put a HF 5th in an otherwise stock si tranny. This make your 5th gear cruise right about 400 rpms lower then before.
3. Is it worth it? Debateable. You'd have to spend a lonnnggg time in 5th to see a MPG benefit. It is a noticeably quieter at 80 mph though.</TD></TR></TABLE>
ok so you can put the 5th gear onto the Si tranny, but the final drive is a no. Ok and the reason was more like a cruisin RPMs type thing. As i remember it was like 4500 to cruise at 75, and the "final drive" on the HF was at 3200 so yeah it'd like to be able to hear better too
Honda-Tech Member
Joined: Nov 2003
Posts: 3,035
Likes: 1
From: DES MOINES, IA/ O.C., USA... EAGLE ROCK, CA
Re: (davens)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by davens »</TD></TR><TR><TD CLASS="quote">1. "Final Drive" is not the same thing as 5th.
2. You can put a HF 5th in an otherwise stock si tranny. This make your 5th gear cruise right about 400 rpms lower then before.
3. Is it worth it? Debateable. You'd have to spend a lonnnggg time in 5th to see a MPG benefit. It is a noticeably quieter at 80 mph though.</TD></TR></TABLE>
2. You can put a HF 5th in an otherwise stock si tranny. This make your 5th gear cruise right about 400 rpms lower then before.
3. Is it worth it? Debateable. You'd have to spend a lonnnggg time in 5th to see a MPG benefit. It is a noticeably quieter at 80 mph though.</TD></TR></TABLE>
Honda-Tech Member
Joined: Apr 2002
Posts: 18,961
Likes: 76
From: I am Tyson
Re: (mr_valentino20032000)
the final drive is the base gearing between the diff (axles) and the input shaft (engine). each gear (1-5) multiplies that final drive ratio for an overall gearing ratio.
for example, on a 21 speed bicycle, you have 3 final drives to choose from, and 7 gears to select. for a car, it would be as if you only have one big gear at the pedal and 5 gears on the rear wheel.
Modified by Tyson at 4:23 PM 11/3/2004
for example, on a 21 speed bicycle, you have 3 final drives to choose from, and 7 gears to select. for a car, it would be as if you only have one big gear at the pedal and 5 gears on the rear wheel.
Modified by Tyson at 4:23 PM 11/3/2004
Thread Starter
Joined: May 2004
Posts: 2,053
Likes: 0
From: FUNK SQUAD, HomeSeven, america
Re: (Tyson)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Tyson »</TD></TR><TR><TD CLASS="quote">the final drive is the base gearing between the diff (axles) and the input shaft (engine). each gear (1-5) multiplies that final drive ratio for an overall gearing ratio.
for example, on a 21 speed, you have 3 final drives to choose from, and 7 gears to select. for a car, it would be as if you only have one big gear at the pedal and 5 gears on the rear wheel. </TD></TR></TABLE>
Thank you for that explanation. I'm so happy that i now understand it. SO i should be able to keep the Si final drive and the HF 5th gear will work right???
for example, on a 21 speed, you have 3 final drives to choose from, and 7 gears to select. for a car, it would be as if you only have one big gear at the pedal and 5 gears on the rear wheel. </TD></TR></TABLE>
Thank you for that explanation. I'm so happy that i now understand it. SO i should be able to keep the Si final drive and the HF 5th gear will work right???
Member
Joined: Nov 2003
Posts: 2,274
Likes: 3
From: 92127
Re: (mr_valentino20032000)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mr_valentino20032000 »</TD></TR><TR><TD CLASS="quote">
Thank you for that explanation. I'm so happy that i now understand it. SO i should be able to keep the Si final drive and the HF 5th gear will work right???</TD></TR></TABLE>
Yes. You need the mainshaft 5th and countershaft 5th from the HF for it to work.
Thank you for that explanation. I'm so happy that i now understand it. SO i should be able to keep the Si final drive and the HF 5th gear will work right???</TD></TR></TABLE>
Yes. You need the mainshaft 5th and countershaft 5th from the HF for it to work.
Thread
Thread Starter
Forum
Replies
Last Post
