Here is the original topic:
http://www.acura-cl.com/ubb/Forum1/HTML/003403.html

Here is the original email:
-----Original Message-----
From: doveyA [mailto:doveyA@email.msn.com]
Sent: Sunday, April 01, 2001 10:29 PM
To: fba
Subject: typeR has a ? about typeR


hey fba long time no speak anyway lots of conversation about the cl over on the boar i frequent...any way there's a dealer called rick case acura and i guess they're the largest acura dealer and they are aggressivelly building a couple monster cl-S' stroking it to 3.5 they built a pressurized version but tranny went by ,by in just 300 miles i remebered the ACR and thought was there any possibllity of sharing any of the work that went into this one i know it was metioned that it had a limited slip diff??? and two what interest me is the 9k tach whats the redline on that thing??? let me know if you can provide any help if not thanks still and keep me up to date on whats up??? hey of the subject...whats the deal on the 2002 accord is there a change ive not heard one rumor or seen one spy photo???

Here is the response from fba:

Well, let's see...understanding that Honda normally designs things using the minimalist approach this could be predicted. The design criteria that were used to ensure reliability in the stock condition will certainly not be adequate if the power is increased significantly. This would be especially true of an automatic 'mission due to the complexity of the device. Putting more power through it would mean that it will definitely need to deal with more load which will also mean higher operating temperatures. A 'mission cooler would probably help but it may not solve the problem. Also, the fluid is a big deal in an AT. There are specific fluids used that have the correct 'friction modifiers' necessary for the correct operation of the 'mission. These are just two possibilities, and I'd suspect both need addressed. With the right preparation, the 'mission should be able to handle significantly more load than stock, but some R&D work might need to be done there. I'd suspect that it hasn't been addressed in that manner. The Accord Coupe R that we created is using a version of the 3.0 l engine originally found in the 1st generation CL. I'm not sure off-hand the power specifications on that 'plant. However, it's Vmax is 280 km/h, this is gear and power limited. One could calculate the peak PS assuming the same coefficient of drag (Cd) and mass from the production Accord Coupe.

The limited slip differential (LSD) is an interesting problem by itself. They are excellent for putting the power to the ground in an efficient manner, but there is a problem with applying them to front wheel drive applications when high torque is available. Straight line accelerations are not a big problem if the system is designed correctly, but during cornering operations with high power, front wheel drive, LSD cars an almost unmanageable amount of torque steer can be generated. This would be dangerous for the average driver with minimal knowledge of the situation. Honda has used Zexel Torsen Type II LSD in Integra R and Accord Euro R to name a few. This is a relatively safe application for a few reasons: First, they are enthusiast cars and the driver typically has a better understanding of performance and handling. Second, these cars have 1.8 l and 2.2 l engines, respectively, that have relatively low torque specifications. On the other hand, the CL S with the 3.2 l has much more torque available than even the 2.2 l from the Accord Euro R / Prelude. The extra power available in the CL S when combined with a LSD can literally rip the wheel from your hands during combined lateral and longitudinal acceleration. An interesting note is the aforementioned medium torque application of the Integra R and Accord Euro R and Prelude. These cars do not generate enough power to create an uncontrollable situation from torque steer alone. They can be very exciting to drive due to the reassuring way that the LSD (Active LSD / ATTS in Prelude) applies the power to the wheel with more grip (normally the outside wheel under typical cornering). This in effect tries to spin the outside wheel even faster actually causing the car to rotate under accelerated cornering. This is in principle the same as staggering the tires on a car, in which the outside wheels on oval tracks are sometimes larger diameter. This makes them cover more track per revolution compared to the inside wheel. This is easily realized by rolling a tapered paper cup on a flat surface. The effect can even be very dramatic. On several occasions I've had my Prelude SH exhibit power on oversteer in accelerated cornering. Normally you can rotate a front wheel drive by trail braking, but because the Prelude SH 'hooks up' so well, it can be easily demonstrated under power.

Increasing the redline of an engine is not a big deal, 9 000 RPM should not surprise. The first thing that needs addressed are the pistons and rods. These must be able to handle the increased stress due to the higher speeds. The second thing is getting enough air into the engine. Just try to drink a coke through a coffee stirrer sometime. No matter how hard you try, there is a flow limit that you'll reach making the attempt futile. This being the reason for restrictor plate racing. The amount of air that you can pull through a given orifice size is directly related to the power output of the engine at WOT. There was significant internal engine work done to the AC-R as well as intake and exhaust work. Increasing the diameter of the throttle body / intake and exhaust system can help an engine flow better, but can have adverse effects on other characteristics. The Honda VTEC system was a big help there. It provides a lower flowing valvetrain for good driveablility at low RPM optimized for efficiency and torque, and the second higher flowing valvetrain for high RPM flow to allow the engine to breath efficiently and keep providing power. Of course, the trend now is to use infinitely variable cam timing / lift / etc. The restrictions are reasons that engine manufacturers use supercharging. Your Honda uses a supercharging technique known as Helmholtz tuning. This is a technique that places the incoming waves of air in or out of phase to in effect push more air into the cylinders.

Anyway, I'm getting a little tired so I'll continue when I get a reply.

Oh, the Accord full model change will take place for the 2003 model year. I'm sure you'll start seeing some spy photos soon as the development is underway.


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Black 2001 Type S
*Eibach Pro-Kit (Waiting to be installed)
*Xephyr Cold Air Intake
*PIAA 19169 Road Lamps
*Rockford 500a2 [FOR SALE]
*Pioneer 12" @ 400w (x2) [FOR SALE]
*77237-SOK-A02
---Still 2 rims not scratched---

[This message has been edited by avengerjr (edited 04-03-2001).]

 

This guy knows his engines and what they can and cant do.

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Dr's car's is stealthy -- able to sneak up on unsuspecting victims

[This message has been edited by DrJeckle and Hyde (edited 04-02-2001).]

 

The following is a list of parts that is in the 300 hp Accord AC-R.

Much of the parts for the Honda Accord AC-R are Honda OEM parts...just from different vehicles. I recommend you go here and print out the grade data for the 2.5 liter V6 Inspire...this is where most of the AC-R stuff comes from. The Inspire 2.5 uses the J25A engine (2.5 liter SOHC V6 with VTEC).

Transmission
First lets start with the transmissions. Many of us think the automatic is not that great and stick would be better...but in this car for the quarter mile there really is no gain in time. Remember with the automatic you only go through three gears where as with a manual you will go through 4 and the 3 to 4 shift time cancels out any gains with a manual. Oh and there is a manual transmission for our car...the NSX transmission will bolt directly to the block...how do I know this...because there is an engine dyno at Honda factory that requires a manual transmission for testing...and they bolt the J series engine to an NSX tranny for testing. But before you go doing the swap you do need stuff like a custom linkage among others.

The AC-R uses the stock transmission modified (or basically a stock 2.5 Inspire transmission), the computer has been adjusted for quicker shifts though...so you would need an after market chip to increase shift speed. The transmission itself is quite strong but because in stock form the shift time is so slow it wears out the tranny faster. The AC-R also uses a different rear end ratio...it uses the rear from the 2.5 Inspire...I think our rear in the Accord is a 4.2, but the rear from the Inspire is a 4.53...which gives you a better overall torque multiplier. I also think the third gear from the Odyssey mini-van is used in place of our stock third gear. By the way they reccommend using a better torque converter to get the revs up from the launch...I would reccommend using Level Ten for this.

Exhaust and Intake
The AC-R uses a custom 2.5 exhaust with no cat...when they race they just unbolt the exhaust from the headers. And about the headers...the header lenghts are not as short as the comptech ones...and by the way the headers were made by DC Sports for Honda as a custom job...I don't think DC Sports will make them.
Now the intake...honda said they experimented with various cold air and short ram intakes...but theres works the best. What they did was take out the resonator...use the stock air box with out a filter and they used like a big piece of plastic tubing from the box into the throttle body (it looked like a modified Iced Tea pitcher).

Top of the Engine
The throttle body is from a CL Type-S as is the Intake Manifold. The Intake Manifold needs a chip to activate the butterfly valve at a certain RPM...I think you can use like a VTEC controller or something to do this. The heads are right from a CL Type-S...that's how they get the revs up so high. I know that they just had the heads extrude honed and I think they are having new cams made too. This is good for us because now Extrude Hone has the molds to do our heads.

The Bottom End
I'm not sure about the connecting rods (I think they are stock) but the Accord AC-R uses the pistons from the Inspire which are the same 86mm bore but are domed which bumps the compression to 11.5 to 1.

Parts List
Here's a quick run down:
Inpire 4.533 rear
Odyssey 3rd gear
Tranny Chip
Upgraded Torque Converter (reccommended)
2.5" Exhaust
DC Sports headers (all though you can only by CompTech's)
Custom Intake
CL Type-S Throttle Body
CL Type-S Intake Manifold with butterfly controller
CL Type-S Heads
Inspire Pistons
Custom hood to fit it all in
Drag slicks



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"the needle got buried at 140.....1,500 RPM later...the tach got buried"

 

ya hopefully more to come
but it sound like and i think the doctor will agree no LSD for us however i did ask him and havent heard back the ACR does have the limited slip and its 300 to the ground so ....the torque must be up there alittle




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'01 3.2 CL typeS
satin silver metalic
Llumar platinum plus
tint 20% all around

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'98 ACCORD V-6 sedan
16" coupe wheels
215/55/16 nitto's
20% smoke titanium
black chrome kit

 

Wow very interesting stuff. I'm impressed.

Had a question though, the upcoming Sentra SE-R Vspec has a Helical LSD, and the Sentra's engine is pretty damn torquey for its size, 180 hp/180 lb.ft, compared to something like the ITR's 195 hp/13x lb.ft

Why Helical?

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Kenny
Slow TL

 

No maintenance, none of the increased drivetrain drag (read: gas hog) of clutch-type LSD that manifests in even normal turning, and torque-sensing eliminates the clutch-type LSD's (rpm-sensing) tendency to increase understeer in FWD cars (the inside wheel will be constantly trying to turn as fast as the outside wheel). And Torsen/helical gear LSDs work better in snow/mud conditions, which builds on an existing strength of FWD design.

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051/LP/SR/LD/HH

 

this is the best post the board has seen, thanks for the info.


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Astroboy out...
2001 Acura CL Type S: Comptech: Headers, filter, sways, springs, koni shocks, goodridge braided brake lines, full kicker system
1996 Porsche 911 Twin Turbo: H&R Springs and sways, Bilstein shocks

 

Interesting, is the IS300's LSD Helical?

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Kenny
Slow TL

 

Wow great post. The information I get from this site daily amazes me everytime.

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CL-S
White/Ebony/Navi/Spoiler/Visor/Full Bra/Mud Guards/Cargo Net/Acura Car Cover/Tint 20%,35%,5% on Sun Roof, Rockford 250a2 Amp w/JL10w6 / K&N Drop in Filter. Comptech Springs. Polarg m-6.
Comptech Headers, Comptech Sways, Eurolite Xenon Crystal high beams.
AEM CAI once they decide to make the dame thing.
235/40/17's or 225/45/17's once I found out which one works for me.

gtech 0-60 6.03 w/ 438 pound load. preheader.

 

Great info guys! TypeR stay on your buddy at Honda R&D about the LSD in the Accord ACR. I think you are on to something. After reading his response, it sounded like maybe Honda felt there is to much liability in installing the LSD's on our cars?
Thanks,
Kevin

 

CLpower i dont know where you got all that info but though the manifold my be whats on our car the ACR was built in 98'and was the dream child of erik berkman it's what spawned our car ...oh and dont take this as me challangeing you comment what im saying is i dont know ...the only thing i do know is the acr has been around alot longer than most would think

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'01 3.2 CL typeS
satin silver metalic
Llumar platinum plus
tint 20% all around

-----------------
'98 ACCORD V-6 sedan
16" coupe wheels
215/55/16 nitto's
20% smoke titanium
black chrome kit

[This message has been edited by typeR (edited 04-03-2001).]

[This message has been edited by typeR (edited 04-03-2001).]

 

Indeed it is. There is also a TRD clutch-type LSD available ($1K) for racing applications (its adjustability and strength offset by its need to be maintained and turning drag.)

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051/LP/SR/LD/HH