92 prelude si. ive heard that if i use the vtec rotors and caliper brackets, then i have the option of then using the stock prelude calipers, or 91-96 nsx calipers (with spacers) or the legend calipers. does any one have pictures of either the nsx or legend calipers. ive heard that the legend calipers are actually bigger but the nsx ones look nicer (who cares). think the legend ones would be better if there bigger. also does any one know what year and model i should get these legend calipers off? also would it be needed to change the master cylinder or the proportioning valve?
it would be greatly appreciated if anyone has information on this topic.
thank you!

 

The NSX calipers don't just look nicer, they're aluminum, so you have less unsprung weight. However, they're like 5 times as expensive. I hear you might be able to score someone's used ones on NSXprime.com.

Dan

 

I have actually seen some pix of a 1995 Prelude Vtec that has had the NSX ones on there...If I can find the pix then I will show you. We will just say, I had to take a second look or a third!

 

 

wow those look good! but i think there gonna be a lil outta my price range. think i gotta go with either the 97+ prelude calipers. or the legend ones. i know the legend calipers have to be from a gs model but thats all. any info on the year and models i could scavange these legend calipers from?
thanx for the info so far.

 

If you don't track the car, the bigger brake upgrade is just expensive rice.

 

The nsx and legend calipers are smaller than the prelude si/vtec calipers but they help move brake bias to the rear some. FYI, the all 90-up preludes have the same size front calipers. Even vtecs. The difference for vtecs is where they have the braket to accept the 1" bigger rotor. The performance gain of that 1" is an 11% increase of brake torque.

 

^^^Good information

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by AndyD &raquo;</TD></TR><TR><TD CLASS="quote">If you don't track the car, the bigger brake upgrade is just expensive rice.</TD></TR></TABLE>
cars dont have to be tracked to be driven hard

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by racerx &raquo;</TD></TR><TR><TD CLASS="quote">The performance gain of that 1" is an 11% increase of brake torque.</TD></TR></TABLE>

how if you use the same pads/rotors? same amount of contact area...

 

You're using the same pads and calpiers for all those ludes I mentioned. The rotor is bigger= more leverage.

 

any clarificaion here? ok i will upgrade to vtec 11" rotors and caliper brackets. but are the legend and vtec calipers really the same? i mean the legend ones are twin piston opposed to the preludes single piston. theres an advantage there. but could they be the same size contact patch? i dunno if that makes too much sense i mean i dont know for sure but the twin piston came on the 2 door and performace gs sedan. and that car wieghed a lot more than the prelude. even if they are the same size than there would still be an advantage to the twin piston design that came on the legend and nsx. right?
any clarification on this topic is greatly appreciated!

 

from what i recall the prelude calipers are single piston?


my setup...

acura legend gs (came in 94-95 not sure of other years but i think thats it) calipers
accord v6 caliper brackets 25mm
accord v6 rotors 25mm
accord v6 pads


the reason i went with the 25 mm pads and rotors because that was my only other option for my accord if i were to upgrade the bigger rotor yet not do rotor over hub conversion.


information for thread starter....
what ever size rotor you get get the accompanying caliper brackets.

the brackets are stamped with the sizes... information i just dug up.
" if using prelude or cl 3.0 rotors, use 23T brackets. have to use 11.2" eitehr way."

edit: one more thing the legends gs dual pistons clamping force are close to the nsx's so thats your next best bet i suppose.

legend caliper brackets = 28t
prelude vtec = 23t

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by racerx &raquo;</TD></TR><TR><TD CLASS="quote">The nsx and legend calipers are smaller than the prelude si/vtec calipers but they help move brake bias to the rear some. FYI, the all 90-up preludes have the same size front calipers. Even vtecs. The difference for vtecs is where they have the braket to accept the 1" bigger rotor. The performance gain of that 1" is an 11% increase of brake torque.</TD></TR></TABLE>

is this true? is there no performance gain to changing the calipers? i will upgrade to the 11" vtec rotors, and the caliper brackets. ur saying that my si calipers are the same as the vtec ones. and are actually better than the legend twin piston calipers? i would think that they would stop better. the legend is heavy. and these were on there performance model. please clarify

 

sorry but im going to doubt racerx's post.

 

im with ya

 

Ya, the si pad is not the same as the vtec pad. Otherwise people would just get the vtec brackets, not the whole caliper when swapping.

However, the vtec pads are the same size as integra type r, legend, and nsx for reference.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by racerx &raquo;</TD></TR><TR><TD CLASS="quote">The nsx and legend calipers are smaller than the prelude si/vtec calipers but they help move brake bias to the rear some. FYI, the all 90-up preludes have the same size front calipers. Even vtecs. The difference for vtecs is where they have the braket to accept the 1" bigger rotor. The performance gain of that 1" is an 11% increase of brake torque.</TD></TR></TABLE>

Nope. The Prelude calipers are both single pot calipers, while the NSX and Legend calipers have duel pots. Therefore the front will clamp more, moving the breaking bias to the front.....which can be detrimental without an adjustable proportioning valve.

Please understand what you're talking about before trying to pass it as the truth.

 

thanx for the help. i dunno if the proportioning valve is the same for si/vtec. but i will change anyway when i upgrade to vtec rotors. but im still unclear. are the si/vtec calipers identical except the brackets? does anybody know if the legend caliper swap requires the swapping of the prop. valve? has anyone done this to thier prelude before??? how does it work???

 

tons of people have done it without getting an adjust. proportioning valve and have had no ill effects - just better stopping.

 

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

Nope. The Prelude calipers are both single pot calipers, while the NSX and Legend calipers have duel pots. Therefore the front will clamp more, moving the breaking bias to the front.....which can be detrimental without an adjustable proportioning valve.

Please understand what you're talking about before trying to pass it as the truth.</TD></TR></TABLE>

i've been thinking about the adjustable proportioning valve for quite some time now. since i've done my brake upgrade i dont know which proportioning valve to go with. i haven't looked too far into it yet but from the little information that i did find on honda-tech there is one that could be obtained from summit racing.

the problem is on summit's website they offer 5 different kinds.


btw: in response to the last poster... the only negative response i think i've experienced is not being used to the stopping power and my wheels having locked up twice and i ended up skidding to a stop.

 

Ludy, I really respect what you know about cars but this is really an area where you're wrong. It doesn't matter if you have one pot or 50 pots. What matters is the combined surface area of the pots.

Go to the end of the post for all the math comparing the vtec and legend calipers.
https://honda-tech.com/zerothread?id=579618

This is for a 5g. Check the p/n for the caliper pot.
http://www.hondaautomotivepart...BRAKE

This is for a 4g. Check the p/n for that pot.
http://www.hondaautomotivepart...81%29

The 3g calipers are built by a different company so the pot numbers different too. But if you go to Advanced and ask for their brake reman book you can check the part numbers for 3rd, 4th, and 5th gens and see that the're all the same. Except for the 88-89 S's. I've also compared the physical si and vtec caliper pots myself and they were the same. Infact, I even believe that the calipers can be used on a 2g. But the only proof I had was a bunch of p/n cross referencing between the 3g accord and prelude.

 

Well assuming Kotetu's facts are correct, I was indeed ignorant on the subject. I always assumed that the dual pots were around the same size as the Prelude's stock single, pretty much ensuring that both would have a lot more surface area than the single.

After reading that first thread, I am lead to believe that installing the Legend calipers will lead to a decrease in lower stopping force:

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Kotetu &raquo;</TD></TR><TR><TD CLASS="quote">Here's an example, with 600PSI exerted through the BMC:

P=600 psi
cF=.33

Rotors:
D1=11inches
D2=10.5inches

Force on rotor = (Pressure*piston Area) * (brakepad Coefficient of Friction) * (2 pads)

Braking torque = fR * (radius-1)/12inches per foot

Stopping force (on tire) = bT / ((wheel radius)/12inches per foot)

Force on Rotors (pounds):
fR1=(600*3.976)*(.33)*(2)=1574.5 //front brake with stock caliper
fR1a=(600*3.905)*(.33)*(2)=1546.38 //front brake with twin piston caliper
fR2=(600*1.4)*(.33)*(2)=554.4 //rear brake

Braking Torque (foot-pounds):
bT1 = 1574.5 * (11/2-1)/12=590.5 //front brake with stock caliper
bT1a = 1546.38 * (11/2-1)/12=579.8925 //front brake with twin piston caliper
bT2 = 554.4 * (10.5/2-1)/12=196 //rear brake

Stopping Force (pounds):
sF1=590.5/((20/2)/12)=708.5 //front brake with stock caliper
sF1a=579.8925 / ((20/2)/12) = 695.871 //front brake with twin piston caliper
sF2=196/((20/2)/12)=235.6 //rear brake
</TD></TR></TABLE>

So the Legend/NSX brakes are actually a downgrade???

 

It surprised the hell outa me too. I still see it as an upgrade compared to my stock si front brakes. The heat problems aren't there any more (not even on deals gap), theres better braking due to the larger rotors, you can manipulate the brakes better from the increased volume inside the legend caliper giving more pedal throw, and it moves the bias towards the rear a little. If anything, it gets rid of some of the safety magin from the factory.

I did a test a while back to see what the f/r heat bias was. It was between a friends 5g with open 17" wheels and stock brakes and my 4g with legend calipers and the closed stock wheels. Besides the front calipers, the 5g's bigger booster, and the perp valve the brakes are identical. We found that even though my front wheels were closed, my front brakes ran cooler by as much as 6%. My rear brakes, however, were 17% hotter than the 5g's. The overall heat bias ended up being 60/40 for my 4g and 66/34 for the 5g. So there is some benefits.

I'm not sure what to think as far as an aftermarket perportioning valve goes. I was lead to believe that some of the perportioning is done in the abs itself. I got a brake pressure guage to see how the cars are perportioned but I never got around to it. If you plan on keeping abs and it does do some perportioning, you'll have to scavenge some of the front brake pressure through a one way valve into the rear brake lines. This is all hypothetical though. I really need to do the pressure tests to be sure.

If you wanted a little more edge and don't mind the extra throw, you could also install an s model mc. Its 15/16" compared to the si/vtecs 1". With the same brake line pressure it would take a little less leg muscle to get there. Maybe about 20 lbs less pedal pressure. This would allow for more brake line pressure with the same amount of pedal pressure and a higher pressure limit. You could change the pedal ratio to do the same thing with the 1" bore mc but the pushrod angle to the mc would be increased some lowering the lifespan of it. BTW, 1" mc bore is the biggest mc honda made up to 2001.

 

If you look at the braking figures for the NSX in one of the major magazines, it's not impressive: 120 feet from 60. That's really not that good for a 90 thousand dollar superexotic.

A G35 does it in 109, for instance.