Accord_V6_400m

iTrader: (1)

Haha, didn't even notice you post there Siggy. 9000rpm will give you an idea of how the big bang got started.

SIRSIG

lol.

if you ask me it's still possible to get 9kRPM. ofcourse with engine mods... upgraded cams, valve, retainers, rockers, springs, etc... stroke and bore too, which will not be talking about J32 engines anymore maybe that's why you said it's overkill for this engine as far as i know we have some of those stuff above mention similar to S2000s' where there is an aftermarket support... to make everything more complicated, fooling the ecu for the rev limiter

mrsteve

iTrader: (1)

You wouldn't want to increase the stroke any more. That's what is going to increase the piston speed at 9,000 RPM.

The J35 internals at 9,000 RPM would travel nearly 28m/s vs a F1 engine which travels at 25m/s

SIRSIG

on the J35 internals yeah, but not sure on the upgraded ones... will see... still trying to figure it out tho...

mrsteve

iTrader: (1)

The issue becomes friction between the piston and the cylinder walls.

I'm telling you, if Honda decided they needed to lower the redline on the AP2 S2000 because the increase in stroke was causing the piston to move too quickly at 8,900 RPM I wouldn't doubt they had good reason to do so. No need for you to go exploring an uncharted territory when the outcome is predisposed for failure.

SIRSIG

i thought it was hp issue reason why they did that

i thought horsepower becomes an issue due to vibration that it creates, spark and the heads aren't working properly due to vibration that's why the engine's power is not upto par... they can solve that problem and stayed 9Krpm but they decide not to because it adds up to the price of the car...

i guess you're right, this just giving me a headache, i'll just buy a faster car

typeR

dont be so quick ! there's no doubt the ECU does it ! but where does it get the info? if there's a trigger from the rpm gauge then this makes perfect sense...maybe the kids vtec has been changed to but it would be to the 4800 rpm close enough to this 4600 that he's saying based on noise

typeR

watched his video ...i dont know looks like 6500 maybe 6600 fuel cut starts ...if 6300 is redline ? whats fuel cut anyone know ? im starting to loose faith... i always believed the ecu got the signal from the wheel speed sensor this is why people will dyno 6800+ rpm s fuel cut when going with tire that are 234/45 a slightly shorter sidde wall... whereas the tach shows the 7100 ...hard to say at this point ...but ive always belived it would be fairly simple to trick the ecu into delaying fuel cut by finding it's trigger...rpm gauge/wheel speed sensor or other...

ThinJim

iTrader: (3)

I have to agree. Sure, the ecu says, "fuel cut", but why does it do that? It seems to make sense that the signal comes from the tach. It would stand to reason if the tach on the P model says fuel cut at 6500 rpm, and the S model says 7100, who knows for sure? Is it a different signal that the ecu responds too? Regardless, it's all speculation from both sides as no one has confirmed where or why the fuel cut occurs. It does seem that his redline increased by changing out the cluster.

As for can the motor handle more rpm, yes. This motor is limited for many reasons, and the one I can tell that is a problem are the valve springs. There set up for about the advertised red line.

CleanCL

iTrader: (4)

you have 2 different part numbers for the ECU, one for the type-s, and one for the non-s. obviously there is something different in there.

BigLizard

I think those specs are wrong because when I dynoed my car the tach smacked 6900 on the graph...not 6300.

fsttyms1

When i get home thursday i can throw in my P gauges and see what happens???

nbennettksu

iTrader: (2)

^doooo it

CleanCL

iTrader: (4)

i just think this is funny. you guys think the ECU adjusts according to the tach on the dash...

from the electrical manual:
"The tachometer drive circuit (part of the main circuit) receives pulses from the PCM. The solid-state tachometer then displays these pulses as engine speed. For each 200 pulses per minute from the PCM the tachometer displays 100 RPM."

so, we have learned, the tachometer display receives it's signal from the powertrain control module. my guess is that the TP sensor is linked to the ecu. the ecu for the type s is told it's higher redline, when TP sensor reads the certain value, it tells it to fuel cut. this is the simplest explanation imo.

mrsteve

iTrader: (1)

No it doesn't have anything to do with making too much horsepower. It had everything to do with piston speed.

Cocoa

iTrader: (2)

MrSteve is 100% correct. I never bothered to do the math as to what it came out to, but I was always iffy about those that wanted to raise the fuel cut off without doing the math that's involved. Me, stroking it to a 3.5L, naturally cannot go as high as whatever the highest rpm the 3.2 can go. Also, for those of you that are familiar with K series, piston speed is the reason as to why those that do the K24 short block with the K20a head has a lower redline than the K20a long block alone. Because of the raised stroke.

Maybe we can just put out the math problem for everyone to see? I have it at home...

typeR

i think the new 3.5HR for nissan has similar stroke and bore and they go 7500 from the factory

typeR

im not suggesting the ECU adj. im asking is there a trigger in the tach @ 7100 that the ecu then responds fuels cut...so the reason for this thread is to gain some knowldge too ...if your saying the tach receives the info from the ecu for rpm,thats fine doesnt completely discount that there could be a trigger in the tach to respond back when fuel cut should be initiated...now tps i dont see it cause you could reach fuel cut at only 25% throttle

mrsteve

iTrader: (1)

The formula is:

Stroke*2*(RPM/1000)/60


The piston speed on a F1 car is about 25m/s
The piston speed on a AP1 S2000 is 24.9m/s
The piston speed of a AP2 S2000 is 24.1m/s
The piston speed of a J32A2 @ 7,2000 RPM is 20.6m/s
The piston speed of a J32A2 @ 9,000 RPM is 25.8m/s
The piston speed of a J35/J32 Hybrid at 7,200 is 22.3m/s

mrsteve

iTrader: (1)

The formula is:

Stroke*2*(RPM/1000)/60


The piston speed on a F1 car is about 25m/s
The piston speed on a AP1 S2000 is 24.9m/s
The piston speed of a AP2 S2000 is 24.1m/s
The piston speed of a J32A2 @ 7,2000 RPM is 20.6m/s
The piston speed of a J32A2 @ 9,000 RPM is 25.8m/s
The piston speed of a J35/J32 Hybrid at 7,200 RPM is 22.3m/s

mrsteve

iTrader: (1)

There is one easy way to solve this. A scan tool hooked up to the OBD2 port and run to WOT. It will show the max RPM

mrsteve

iTrader: (1)

The stroke on the VQ35HR is 81.4mm.

The stroke on the VQ37HR is 86mm just like the J32A2.

They both have a much larger bore @ 95.5mm

So the piston speed on the VQ35HR @ 7,500 RPM is just 20.35m/s

CleanCL

iTrader: (4)

there is a test tachometer plug. it is in the engine bay. it is on the strut tower almost directly underneath the throttle/cruise cables, and to the left of the orange plug that is always in the way of the icebox installs.

p.s. i see no other circuit going from the tach back to the PCM.

typeR

i hear ya and im past thaT...weather it is true that the tach change has affected the fuel cut on this cl-P to cl-S cluster swap...i m almost 100% certain its not from acctual engine speed because same dyno shop if show two different fuel cut rpms...one with 235/45 tires and one with 245/45 tires

CLsuperhero

so to sum this up... block signal from tach to ECU to stop fuel cut? if it is coming from the tach... I think it's purely the ecu causing fuel cut, but the ecu ignores engine speed and gets it's info from something pre-programmed into it to make it shut off at 7100. I don't think it gets it's info from the tach. if the tach effected fuel cut that would mean vtec would only engage if the tach was in a specific position but I think the ecu keeps up with everything and when to kick it in.

I know this sound ghetto but I know basic resistors have been used to block ecu signals in most cases causing a higher rpm idle speed. No real power made there but something to note. what's different about the wires in the CL-P cluster and CL-S cluster? Could it be the amount of electric current traveling through the wires that fools the ecu? I don't want to completely shoot this down but I dunno.

mrsteve

iTrader: (1)

Somethings I would like explained:

What exactly was swapped out? Was it only the plastic gauge face?

Can someone please post a picture of a CL-P tach gauge and a CL-S tach gauge?

CLsuperhero

Not the best pics but it's something I think it's a type S


http://cgi.ebay.com/ebaymotors/01-03...QQcmdZViewItem

BigLizard

That's the CL-P

CLsuperhero

I don't drive a CL-P it looked really close to what I look at everyday in my car. Thanks for the correction.

YeuEmMaiMai

OMG

why would the ECU rely in a grossly INACCURAGE GUAGE when it can use the Crank Position Sensor to figure out RPM? Based upon this insane logic those with broken tachometers would never redline becuase the tac would never reach the switch.

Fuel cutoff is PROGRAMMED INTO THE ECU along with TOP SPEED GOVERNOR

Please, pull your head out of your rear end long enough to think about what you just said.....

The only way to change redline or fuel cutoff is to rewrite the code with the new values for each......lol

want to know why the tach is off? most likely becuase it is calibrated for the CL-S versus the CL-P

tach is controlled by a voltage signal that is sent to it

lets say that at redline the ECU sends 12V to the tach on the CL-P it is calibrated for 6300 and on the CL-S it is 6800. swap a CL-S tach into a CL-P and bingo tach swings to 6800 even though it should read 6300. I would guess that if you did the reverse swap the CL-P tach would redline at 6300 in a CL-S

typeR

well you sound like you must have all the answers... so why then if it was the crank postion sensor DUMB ASS would the car dyno different rpms when wearing different size tires ... why would a coil clamp read 6880 rpms when wearing 235/45 tires and 7150 with 245/45 ? regaurdless the ECU is getting the signal from somewhere clamp that out put and one could have any redline or none... you may wanna read things like the title right below my user name and maybe my join date and sig... then sit back give respectful insight or you may just find yourself taking alittle break from this site ! read that

typeR

i see where you're going and thats a good question ! like i said at this point the where doesnt matter real point of this thread is ...the ecu gets a signal from somewhere find it clamp it delay it...tie it into a vtec controler and it should be able to be manipulated...

poisx7

iTrader: (1)

what he say

typeR

so next best possible to me is wheel speed sensor ...can you take a look

mrsteve

iTrader: (1)

Yes the signal does need to come from somewhere. It's just a matter of determining where and then finding a tool that will allow you to manipulate it.

RUF87

Sorry guy, but that sounds like a corporate statement to me. The redline is set by the factory, and is more often than not it's conservative. I've never had a car that controlled the redline like this car, and I've driven everyone of them past the redline and have never . . . NEVER lost an engine.

This is a Honda engine and its trademark is high reving engines, and I will bet that this engine will handle 7,500.

Ruf

TheWeez

So to summarize.

Everyone agrees that there is no way that changing the gauge cluster changes the actual redline and VTECH engagement. It's just an off gauge or the difference in spacing on the CL-P cluster vs the CL-S cluster.

The engine can likely handle a higher RPM then the factory redline but won't likely benefit unless it's FI. It would need modification to do so such as UPDs and some kinda management to allow it to push past the factory fuel cutoff.

RUF87

You know, you might be taken more seriously if you responded in such a manner.
Your points have merit, but they are lost in the off color commentary BS.

I've been working on cars off and on for over 30yrs and have seen some weird @ss $hit designs, so anything is possible. However, while this does seem unlikely it is an anomaly worth checking out and I believe that is all TypeR is doing.

Ruf

BigLizard

typeR is my hero.

I don't agree with this statement. Lets say you're hypothesis is wrong, the CL-S ECU sends the signal to a CL-P tach, I would think that it would show that the tach would hit 6800 every time, not 6300. Who's to say though, if you think you're right, show us and prove us wrong.

NightRider

From the other thread but still relevant here...