Swapping SH tranny for JDM M2A4
Thread Starter
Joined: Apr 2004
Posts: 7
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From: New Haven, CT
Who wrote this
I would greatly appreciate it, if maybe I can talk to this person. Can anyone tell me who wrote this write up
Quote, originally posted by honda-tech members »
both the base model and the SH have about 200hp to the flywheel. Although when dyno'd and powered measured to the wheels the base model puts out a couple of more horses because the SH looses a bit more power due to the ATTS system robbing some ponies.
The SH prelude ATTS problem with high horsepower is that it shuts off in the range of 220-250 horsepower and becomes useless. The base and the SH have the same engine albeit the SH block is a little different with the oil filter being in a different location than the base prelude to accomodate ATTS.
if you want a drag car, get the base.
if you want a car for auto-xing, track, road courses...etc, get the SH.
you'll find parts easier for the base, for the SH you'll have to hunt.
if you want to go turbo with an SH, you can always disconnect the ATTS unit.
LSD not compatible with ATTS.
ATTS: Active Torque Transfer System.
It basically sends more power to the outside wheel when cornering making it spin 15% faster than the inside wheel.
both base and SH models are identical when it comes to the engines power at the flywheel. The SH has some accessories that the base model does not have such as a leather shift ****, spoiler, different rims, and some others
front suspension is different on the SH (biggest thing people dont realize). the geometry is different (specially designed to reduce torque steer) and the exhaust routing is slightly different to accomodate the ATTS.
The SH has a different block, it's a fact. That's why the SH and Base trannies is not a bolt on swap. Internally they are the same, but the block design on the outside is differnt. Intermediate shaft and tranny mounting, oil filter and a bunch of other stuff.
There is a thread on PO.com that details how to do a SH tranny swap to a base, it's not easy and involves fabrication.
The swap to a base tranny is NOT DIFFICULT. Trust me, I've done it...they are my pictures on preludeonline. The _only_ difference is the SH block has mounting points for the ATTS unit instead of an intermediate shaft. The modification to bolt an intermediate shaft up only takes a little bit of work to the bearing carrier of the shaft as well as the fabrication of an adapter plate (which is simply a drilled piece of 1/4" plate). You can retain your SH axles and nothing else changes...you only need a base tranny and intermediate shaft. My pics are here:
http://ian.clendaniel.net/gallery/noatts
Yeah, the front suspension difference shouldn't be a deterrant - it's really not a big deal. Just replace the springs & shocks together.
There is a small difference in the exhaust manifold - the SH collector ends a few inches farther downstream than the base.
The oil filter is in a different location on the block, but all that means is if you get a JRSC kit, it needs to be relocated.
All the other issues all revolve around the ATTS system. Like has been mentioned already, in high powered applications (turbo, supercharger, or extreme n/a), it will have trouble handling the power. If you just want nitrous, you might be alright since you're not spraying all the time. And you're not likely to spray around too many corners where the ATTS would actually be operating.
You also won't be able to install a limited slip differential at the same time as the ATTS - if you decide you want one, a tranny swap & mild custom fabbing will be in order. And if you decide to go to a stand-alone management system like Hondata or AEM, you'll lose the ATTS functions.
And then there's those few extra pounds up front. **shrug**
All of that said, there are definitely advantages to the SH model - little things like the courtesy lights on the doors, leather wrapped shift ****, the spoiler & brakelight-less rear deck, stuff like that is nice. And of course, within it's boundaries, the ATTS works very well at getting rid of understeer. It's extremely fun on highway on-ramps . . .
-SH does not have more power. auto preludes (5G) all have 190hp, Manuals have 195hp (1997, 1998) and 200hp (1999-2001). SH come ONLY in manual
-the difference in hp was never quite accounted for, some say the 97-98 were underrated, some say it was just ecu tuning, either way it's not a big difference
-SH and base lude differ mainly because the SH has ATTS, which essentially makes the front wheels turn like a tank when you turn hard (more torque to the outside wheel)
-other than that, the suspension differs in that the upper and lower control arm designs were changed to reduce torque steer. it is slightly stiffer too.
There are actually quite a few differences between the base and the Type SH suspension, The springs are not the same. The type SH springs are a little taller. The struts are different as well, the base where the spring is perched sits lower on the Type SH, hence the taller spring. It results in a little firmer spring rate than the base. Lets not forget to mention the front knuckles are different, the raius rods, the front trailing arms, and the roll bars are a couple of millimeters thicker than the base front and rear. In the rear the springs and struts are different on the SH, it has the same condition as the front where the perch that the spring sits on is slightly lower than the base model, and the spring is slightly taller than the base model, It is not as big of a difference between the SH and Base rears as the fronts are though, the rear trailing arms are a little thicker as well but not much. The only problems with aftermarket struts would be modifying the dust gaurds on the struts with stock springs, however if you go aftermarket springs and struts that are replaced in tandem you will not run into any issues..
Here is a brief synapse of what ATTS is and what it does. under straight line acceleration the system operates like an open diff meaning that only one wheel will spin on a slick surface (eg.. like ice), also at the track it only spin one tire just like an open diff. There for ATTS is not an lsd. ATTS is located on the left axle, it is essentailly a smaller tranmission, it hydraulically activates gears in the unit to route the power.When you are traveling at speed and you corner there are senors measuring the cornering force, speed, and throttle input and can send as much as 80% torque to the outside wheel when cornering. There is a standalone unit that controls the ATTS unit itself, it is also connected to the ECU. So if there is any imminent danger to the ATTS it will tell the ECU to cut power.
Honda redesigned its sport coupe for 1997. Again front-wheel drive with a 4-cylinder engine, Prelude rode a 1.4-inch longer wheelbase than before, and measured 3.2 inches longer overall. Curb weight rose by 145 pounds. Interior dimensions changed only slightly, but trunk space expanded by nearly one cubic foot. Basic 2-door notchback styling continued from the 1992-96 generation, but traditional analog gauges replaced vacuum-fluorescent instruments. Only base and SH editions went on sale, each equipped with a 2.2-liter 4-cylinder that employed Honda's variable-valve-timing technology. Running on premium fuel, the engine developed 195 horsepower with 5-speed manual shift, but only 190 horses when equipped with an automatic transmission. Offered only on base Preludes, the automatic transmission gained a new manual-shift feature, called Sequential SportShift. The gear selector lever could be left in Drive for regular automatic shifting, or tipped forward or backward to permit manual gear selection.The SH model went on sale first, equipped with a new Honda-developed system designed to combat the tendency of front-drive cars to plow, or understeer, when accelerating through a turn. Called the Active Torque Transfer System, it automatically distributed more of the engine's power to outside front wheels when accelerating in a turn. That forced the outside front wheel to rotate up to 15 percent faster than the inside front wheel. The system could direct up to 80 percent of engine torque to a single wheel. Dual airbags and four-wheel disc brakes were standard on both models, incorporating antilocking. Each model rode 16-inch tires.
Year-to-Year Changes
1998: New paint colors were the only change for 1998.
1999: More new colors became available, but only one interior hue: black. The Prelude's engine gained 5 horsepower, and did not require a tune-up until 100,00 miles. Remote locking now was a standard feature.
2000: Preludes entered the 2000 model year without change.
2001: Standard floormats, rear child-seat tethers, an emergency trunk release were the main changes for 2001. Prelude would not continue for 2002.
Quote, originally posted by honda-tech members »
both the base model and the SH have about 200hp to the flywheel. Although when dyno'd and powered measured to the wheels the base model puts out a couple of more horses because the SH looses a bit more power due to the ATTS system robbing some ponies.
The SH prelude ATTS problem with high horsepower is that it shuts off in the range of 220-250 horsepower and becomes useless. The base and the SH have the same engine albeit the SH block is a little different with the oil filter being in a different location than the base prelude to accomodate ATTS.
if you want a drag car, get the base.
if you want a car for auto-xing, track, road courses...etc, get the SH.
you'll find parts easier for the base, for the SH you'll have to hunt.
if you want to go turbo with an SH, you can always disconnect the ATTS unit.
LSD not compatible with ATTS.
ATTS: Active Torque Transfer System.
It basically sends more power to the outside wheel when cornering making it spin 15% faster than the inside wheel.
both base and SH models are identical when it comes to the engines power at the flywheel. The SH has some accessories that the base model does not have such as a leather shift ****, spoiler, different rims, and some others
front suspension is different on the SH (biggest thing people dont realize). the geometry is different (specially designed to reduce torque steer) and the exhaust routing is slightly different to accomodate the ATTS.
The SH has a different block, it's a fact. That's why the SH and Base trannies is not a bolt on swap. Internally they are the same, but the block design on the outside is differnt. Intermediate shaft and tranny mounting, oil filter and a bunch of other stuff.
There is a thread on PO.com that details how to do a SH tranny swap to a base, it's not easy and involves fabrication.
The swap to a base tranny is NOT DIFFICULT. Trust me, I've done it...they are my pictures on preludeonline. The _only_ difference is the SH block has mounting points for the ATTS unit instead of an intermediate shaft. The modification to bolt an intermediate shaft up only takes a little bit of work to the bearing carrier of the shaft as well as the fabrication of an adapter plate (which is simply a drilled piece of 1/4" plate). You can retain your SH axles and nothing else changes...you only need a base tranny and intermediate shaft. My pics are here:
http://ian.clendaniel.net/gallery/noatts
Yeah, the front suspension difference shouldn't be a deterrant - it's really not a big deal. Just replace the springs & shocks together.
There is a small difference in the exhaust manifold - the SH collector ends a few inches farther downstream than the base.
The oil filter is in a different location on the block, but all that means is if you get a JRSC kit, it needs to be relocated.
All the other issues all revolve around the ATTS system. Like has been mentioned already, in high powered applications (turbo, supercharger, or extreme n/a), it will have trouble handling the power. If you just want nitrous, you might be alright since you're not spraying all the time. And you're not likely to spray around too many corners where the ATTS would actually be operating.
You also won't be able to install a limited slip differential at the same time as the ATTS - if you decide you want one, a tranny swap & mild custom fabbing will be in order. And if you decide to go to a stand-alone management system like Hondata or AEM, you'll lose the ATTS functions.
And then there's those few extra pounds up front. **shrug**
All of that said, there are definitely advantages to the SH model - little things like the courtesy lights on the doors, leather wrapped shift ****, the spoiler & brakelight-less rear deck, stuff like that is nice. And of course, within it's boundaries, the ATTS works very well at getting rid of understeer. It's extremely fun on highway on-ramps . . .
-SH does not have more power. auto preludes (5G) all have 190hp, Manuals have 195hp (1997, 1998) and 200hp (1999-2001). SH come ONLY in manual
-the difference in hp was never quite accounted for, some say the 97-98 were underrated, some say it was just ecu tuning, either way it's not a big difference
-SH and base lude differ mainly because the SH has ATTS, which essentially makes the front wheels turn like a tank when you turn hard (more torque to the outside wheel)
-other than that, the suspension differs in that the upper and lower control arm designs were changed to reduce torque steer. it is slightly stiffer too.
There are actually quite a few differences between the base and the Type SH suspension, The springs are not the same. The type SH springs are a little taller. The struts are different as well, the base where the spring is perched sits lower on the Type SH, hence the taller spring. It results in a little firmer spring rate than the base. Lets not forget to mention the front knuckles are different, the raius rods, the front trailing arms, and the roll bars are a couple of millimeters thicker than the base front and rear. In the rear the springs and struts are different on the SH, it has the same condition as the front where the perch that the spring sits on is slightly lower than the base model, and the spring is slightly taller than the base model, It is not as big of a difference between the SH and Base rears as the fronts are though, the rear trailing arms are a little thicker as well but not much. The only problems with aftermarket struts would be modifying the dust gaurds on the struts with stock springs, however if you go aftermarket springs and struts that are replaced in tandem you will not run into any issues..
Here is a brief synapse of what ATTS is and what it does. under straight line acceleration the system operates like an open diff meaning that only one wheel will spin on a slick surface (eg.. like ice), also at the track it only spin one tire just like an open diff. There for ATTS is not an lsd. ATTS is located on the left axle, it is essentailly a smaller tranmission, it hydraulically activates gears in the unit to route the power.When you are traveling at speed and you corner there are senors measuring the cornering force, speed, and throttle input and can send as much as 80% torque to the outside wheel when cornering. There is a standalone unit that controls the ATTS unit itself, it is also connected to the ECU. So if there is any imminent danger to the ATTS it will tell the ECU to cut power.
Honda redesigned its sport coupe for 1997. Again front-wheel drive with a 4-cylinder engine, Prelude rode a 1.4-inch longer wheelbase than before, and measured 3.2 inches longer overall. Curb weight rose by 145 pounds. Interior dimensions changed only slightly, but trunk space expanded by nearly one cubic foot. Basic 2-door notchback styling continued from the 1992-96 generation, but traditional analog gauges replaced vacuum-fluorescent instruments. Only base and SH editions went on sale, each equipped with a 2.2-liter 4-cylinder that employed Honda's variable-valve-timing technology. Running on premium fuel, the engine developed 195 horsepower with 5-speed manual shift, but only 190 horses when equipped with an automatic transmission. Offered only on base Preludes, the automatic transmission gained a new manual-shift feature, called Sequential SportShift. The gear selector lever could be left in Drive for regular automatic shifting, or tipped forward or backward to permit manual gear selection.The SH model went on sale first, equipped with a new Honda-developed system designed to combat the tendency of front-drive cars to plow, or understeer, when accelerating through a turn. Called the Active Torque Transfer System, it automatically distributed more of the engine's power to outside front wheels when accelerating in a turn. That forced the outside front wheel to rotate up to 15 percent faster than the inside front wheel. The system could direct up to 80 percent of engine torque to a single wheel. Dual airbags and four-wheel disc brakes were standard on both models, incorporating antilocking. Each model rode 16-inch tires.
Year-to-Year Changes
1998: New paint colors were the only change for 1998.
1999: More new colors became available, but only one interior hue: black. The Prelude's engine gained 5 horsepower, and did not require a tune-up until 100,00 miles. Remote locking now was a standard feature.
2000: Preludes entered the 2000 model year without change.
2001: Standard floormats, rear child-seat tethers, an emergency trunk release were the main changes for 2001. Prelude would not continue for 2002.
Member
Joined: Apr 2003
Posts: 2,289
Likes: 0
From: Windsor, PA
Re: Who wrote this (phat81)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by phat81 »</TD></TR><TR><TD CLASS="quote">I would greatly appreciate it, if maybe I can talk to this person. Can anyone tell me who wrote this write up
</TD></TR></TABLE>
I searched the archives and compiled all that information. Technically about 20 people wrote that.
Anyway, what is your question?
</TD></TR></TABLE>
I searched the archives and compiled all that information. Technically about 20 people wrote that.
Anyway, what is your question?
Thread Starter
Joined: Apr 2004
Posts: 7
Likes: 0
From: New Haven, CT
Re: Who wrote this (Behan)
The reason why I ask who wrote that. Was for the fact that I have a 2000 H22A4 SH engine that I don’t know that I should keep or not. But I saw on the website on that write-up that a fabricated plate can be made to have the half shaft hookup. They other question was that since I got ride of the atts tranny, I bought a M2A4 jdm base model tranny, will that hookup to the sh block without any complications, and I think I would have to run a base model wire harness instead of the sh wire harness since that has the atts wired in it. By the way I do have the base model obd2 wire harness so that kind of saves me the trouble you know also if you have done this swap to your car. Please if there is some way that I can talk to you I would greatly appreciate it thanks
Member
Joined: Apr 2003
Posts: 2,289
Likes: 0
From: Windsor, PA
Re: Who wrote this (phat81)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by phat81 »</TD></TR><TR><TD CLASS="quote"> But I saw on the website on that write-up that a fabricated plate can be made to have the half shaft hookup. They other question was that since I got ride of the atts tranny, I bought a M2A4 jdm base model tranny, will that hookup to the sh block without any complications.</TD></TR></TABLE>
Yes the base model will bolt up. That is what the write up is describing, modifying your block to accept the base model tranny/ halfshaft. All you need is the base tranny/halfshaft and to fab that plate up.
If you would like to talk to clendaniel directly you should find an email link here http://ian.clendaniel.net/
I'm not sure about the wiring harness question though
Yes the base model will bolt up. That is what the write up is describing, modifying your block to accept the base model tranny/ halfshaft. All you need is the base tranny/halfshaft and to fab that plate up.
If you would like to talk to clendaniel directly you should find an email link here http://ian.clendaniel.net/
I'm not sure about the wiring harness question though
I live under a rock
Joined: Apr 2003
Posts: 11,107
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From: Purple Prelude, DE
Re: Who wrote this (Behan)
Thatd be my buddy Ian who wrote/did that...... he is clendaniel on here.... just post your questions though...... he is usually very busy durning the week
Junior Member
Joined: Aug 2001
Posts: 313
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From: Bear, DE, USA
Re: Who wrote this (spoolinlude)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by spoolinlude »</TD></TR><TR><TD CLASS="quote">Thatd be my buddy Ian who wrote/did that...... he is clendaniel on here.... just post your questions though...... he is usually very busy durning the week</TD></TR></TABLE>
Ehh...to be modest I only wrote the small portion about swapping the trannies.
--Ian
Ehh...to be modest I only wrote the small portion about swapping the trannies.
--Ian
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Member
Joined: Mar 2002
Posts: 8,113
Likes: 3
From: East Village, NYC
Re: Who wrote this (spoolinlude)
wiring harness wise I don't think you have a problem you just ignore the Atts plugs and pieces there the atts is controlled by a seperate unit the only thing the ecu does to my knowledge is send some power to the ATTS unit. you can run the SH ecu without the ATTS
Junior Member
Joined: Aug 2001
Posts: 313
Likes: 0
From: Bear, DE, USA
Re: Who wrote this (satan_srv)
Exactly...just leave the harness as it is, pull the ATTS control unit (mounted right next to the main ecu) and put it in your closet to collect dust. You won't have any codes or CELs to worry about... 
--Ian
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by satan_srv »</TD></TR><TR><TD CLASS="quote">wiring harness wise I don't think you have a problem you just ignore the Atts plugs and pieces there the atts is controlled by a seperate unit the only thing the ecu does to my knowledge is send some power to the ATTS unit. you can run the SH ecu without the ATTS</TD></TR></TABLE>
--Ian
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by satan_srv »</TD></TR><TR><TD CLASS="quote">wiring harness wise I don't think you have a problem you just ignore the Atts plugs and pieces there the atts is controlled by a seperate unit the only thing the ecu does to my knowledge is send some power to the ATTS unit. you can run the SH ecu without the ATTS</TD></TR></TABLE>
Honda-Tech Member
Joined: Jan 2004
Posts: 2,889
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From: Orange County, CA
Re: Who wrote this (clendaniel)
ill be doing this in due time. have other problems to worry about, such as getting dynoed and my hood lifting and eventually letting go and smashing into my windsheild. hoodpins today 
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