Another Hondata thread

[Soon2beEP3]

Ok I know everyone has worn out the Hondata threads. I think I finally found out what I want to do with my engine. I have an Injen shortram and I was thinking ebay muffler $35 and custom exhaust. Maybe RSX headers because I heard all you need is the donut gasket from the RSX to make them fit. Anyways, I read a thread on here that said it wouldn't be good to put a lighter flywheel on our engine because when we shift rpms drops down below v-tec, when we want to stay in the v-tec. If I were to get Hondata and rpms are pushed up, with a lighter flywheel it would drop somewhere around peak power? I'm just looking for more top end and a lighter flywheel(9lbs) w/Hondata would help right?

[myeverlovinsir]

Flywheel is not going to effect your vtec engagement.(2200rpm) A lighter fly helps with acceleration due to less inertia on the crank.

[Soon2beEP3]

So with or without Hondata a lighter flywheel will help because the engagement of the v-tec is at 2200 rpms?

[myeverlovinsir]

They are not related that way. A lighter fly will help any engine no mater where vtec is. Hondata does not change the vtec engagement of the A3.

[Soon2beEP3]

Thank you Myeverlovinsir, I want to do a K20a engine swap in a few years and I'm just looking for more power until then without doing a head swap or F/I. It seemed my car was lacking top end power and I was just searching for solutions.

[tcostello3]

The weight of the flywheel affects boosted engines more than n/a. However a super light flywheel is not to great for daily stop and go ride the clutch driving. It spins down much faster when the cluth is engaged (think centrifugal force) so when you re-engage at low rpms you'll fell a clunk drop into gear. The key is to get a mid weight flywheel maybe 11.5-15lbs.

This comes from personal driving experience and could different for your needs.

[Dunrick]

Originally posted by myeverlovinsir
They are not related that way. A lighter fly will help any engine no mater where vtec is. Hondata does not change the vtec engagement of the A3.

Your right for our engine. But he has a point. When your flywheel is lighter, the rpms will drop faster therefore landing you lower in the rpms for the next shift, unless you shift like superman.

But since we are always in our wussy vtec from 2,2k rpms and up, this wont be a problem. Get a middle-weight clutch like tcostello3 said.

[SiGuy]

Not to be a smart ass or anything but our 2nd intake valve opens at 2200. Our cam shift happens at about 4500, shifts back to normal lobes at about 4200. So vtech starts at about 4500.

[myeverlovinsir]

The rpms will raise and drop quicker between shifts if you let them. I try to rev match the next gear. I will be running an 8lb Fidanza fly in the new tranny with real vtec. Should be interesting.:D

[myeverlovinsir]

Originally posted by SiGuy
Not to be a smart ass or anything but our 2nd intake valve opens at 2200. Our cam shift happens at about 4500, shifts back to normal lobes at about 4200. So vtech starts at about 4500.

x-over for the A3 head is @2200rpm, nothing more happens with the cams after that. The 4500rpm power you feel is simply resonating tq.

[Vertigo]

Originally posted by myeverlovinsir
x-over for the A3 head is @2200rpm, nothing more happens with the cams after that. The 4500rpm power you feel is simply resonating tq.
HAHAHA..Will they ever learn? The A3 is basicly a 12 valve engine below 2200 rpm. Above 2000 rpm to rev-limiter all 16 valves are working. Honda did this for economy and emissions.

[SiGuy]

Hmmm. I still have to dissagree, but I'm gonna check with my Honda tech on that x-over rpm. No disrespect, but I just can't see the point of having the other lobe if we switch at 2200, with or gears we are hardly ever below 2200.

[tcostello3]

btw..All of this is irrelevant for the first 2 gears until you drop the cash on an lsd! which I would do at the same time since your'e gonna be in the tranny case anyways. Here's your typical n/a street setup: 11.5-15lb Flywheel, 200% overstock clutch disc, & lsd!

VVVRRROOOOOMMMMM!

[Hatch02SI]

Originally posted by SiGuy
Not to be a smart ass or anything but our 2nd intake valve opens at 2200. Our cam shift happens at about 4500, shifts back to normal lobes at about 4200. So vtech starts at about 4500.


This post would be worth something if you could explain how we vtech and not i-vtec... Not to be a dick just trying to set those who r lost right :)

[tcostello3]

Si vtec is around 4500
Ex vtec is around 4200 and btw single cam sucs arse! bring me boost!

get an VFAC and you'll not only see this right away but you then change the vtec engagement for each gear to suit your style.

[SiRman]

Not to be a smart ass or anything but our 2nd intake valve opens at 2200. Our cam shift happens at about 4500, shifts back to normal lobes at about 4200. So vtech starts at about 4500.


Si vtec is around 4500


You guys are sadly mistaken in your k-series knowledge.

Start by reading:

http://www.hondata.com/techk20general.html

http://asia.vtec.net/article/k20a/index.html

[SiGuy]

Ok. So I'm lost?? Then let me exlain our i-vtech briefly. It is a three stage vtech. The first stage is when our 2nd intake valve opens at 2200 rpm. There is NO cam shift at this stage. Our 2nd stage is when the varible timing control kicks in and adjusts the timing by advancing or retarding the phasing on the intake cam by 30 degrees offset. The third and final stage is when the cam shift happens at about 4500 rpm. I use vtech generically to refer to our cam shift. There is actually a very in depth description of this system with illustrations on this forum that I read a few months ago. I forgot where I got this info until today. If you are still a disbeliever, search it. Again no disrespect intended.
Have a happy honda day.

[SiGuy]

I just double checked my techs manual. It's actually up to 50 degrees of offset with the vtc, and it's dependant on many factors such as but not limited to engine speed and oil pressure.

2003 silver Si aem cai, dc 4to1 header
DEAD
2003 white Si, bone stock-for now

[sniperSI]

Originally posted by SiGuy
Ok. So I'm lost?? Then let me exlain our i-vtech briefly. It is a three stage vtech. The first stage is when our 2nd intake valve opens at 2200 rpm. There is NO cam shift at this stage. Our 2nd stage is when the varible timing control kicks in and adjusts the timing by advancing or retarding the phasing on the intake cam by 30 degrees offset. The third and final stage is when the cam shift happens at about 4500 rpm. I use vtech generically to refer to our cam shift. There is actually a very in depth description of this system with illustrations on this forum that I read a few months ago. I forgot where I got this info until today. If you are still a disbeliever, search it. Again no disrespect intended.
Have a happy honda day.


Yes all that is true (to a certain degree) with the k20a2 k20a and any other honda k series engine EXCEPT for the SI. We have vtec, but its only to help the car at idle speeds so it can get the LEV certification. A combustion engine is most ineffcient at idle. Once the higher lobes kick in @ 2200 (again that lobe is purely for emissions) and the last 4 valves kick in, then the only thing we have is the VTC system which adjusts the overlap of the intake cam.

We do not have a REAL vtec system like prior gens. or other k series engines. Take a look at our cams if you have a chance. You'll see what we're refering to.

[!@#$%]

yep, only 2 lobes on intake shaft and 1 on exhaust.

[myeverlovinsir]

A3 on top and A2 on bottom...

http://a5.cpimg.com/image/15/D7/29869845-ac91-01550200-.jpg

A2 head and cams
http://a6.cpimg.com/image/50/E9/29870416-15fd-02000180-.jpg

A3 head and cams
http://a8.cpimg.com/image/52/E9/29870418-5be5-02000180-.jpg

[SiRman]

The first stage is when our 2nd intake valve opens at 2200 rpm. There is NO cam shift at this stage.

How exactly does the other valve open then?
2200rpm is when the A3 switches to the cam lobes that open both intake valves.

[Silverstreak]

2200 rpms is the x-over. No matter what you think or hear. That is all the si has. Shitty, yes i know.

[Dunrick]

Its funny, you cant even feel it. I have purposely gone to about 1.8k rpms in third, and floored it. There is nothing to feel at 2.2k rpms. I'm not saying thats not the xover, it is. I'm just saying, its so pathetic.

[SiGuy]

Well dammit. After talking to my tech and reding trough his manuals, it looks like I'm wrong on the cross over. That does make since that would be the only way the other intake valve could open. With my cai on my other ep(haven't had a chance to put it on my new one) you could hear a deepening, throaty sound sound at 2200 rpm. With the header and cai I got a definate power surge at 4500. Apparently, in my reading I confused the ep with a ex. The cam x over does happen at 2200. Can anybody help me get a a2 head? I think that would be a better investment than i/h/e for about the same money.

[Dunrick]

you are pretty bold to come into a ep only website and say were all wrong on the xover haha...

i'm glad to see you own up. Thats a good quality. If your stupid like me, it becomes a daily thing to own up.


http://chumpco.com/~snicker/pix/art/im-with-stupid.jpg

[SiGuy]

Whoa! I admitted I was wrong. There is no need to insult me with Uncle Sam. Besides, remember what your mother told you about pointing!

[sniperSI]

Originally posted by SiGuy
Well dammit. After talking to my tech and reding trough his manuals, it looks like I'm wrong on the cross over. That does make since that would be the only way the other intake valve could open. With my cai on my other ep(haven't had a chance to put it on my new one) you could hear a deepening, throaty sound sound at 2200 rpm. With the header and cai I got a definate power surge at 4500. Apparently, in my reading I confused the ep with a ex. The cam x over does happen at 2200. Can anybody help me get a a2 head? I think that would be a better investment than i/h/e for about the same money.


The surge of power and sound is because the cams start moving into full overlap starting at 4k i think. The larger sound is because the overlap between the 4 valves because the engine is more OPEN at higher RPM with the vtc.



Its funny, you cant even feel it. I have purposely gone to about 1.8k rpms in third, and floored it. There is nothing to feel at 2.2k rpms. I'm not saying thats not the xover, it is. I'm just saying, its so pathetic.


Go about 40 mph in 3rd gear, your rpms should be below 2000 or right on about, then floor it you can feel a tiny surge.

[SiGuy]

Well, apparently in 06 we are going to get "increased performance". Could it be a true god love it vtech? In coupe form too. I'm a little pissed but I plan on having a a2 head and boost by then.

[Tenacious G]

Originally posted by SiGuy
There is NO cam shift at this stage. Our 2nd stage is when the varible timing control kicks in and adjusts the timing by advancing or retarding the phasing on the intake cam by 30 degrees offset.

also, fyi ... the VTC can only advance timing, not retard it.

[myeverlovinsir]

VTC CAN advance or retard the intake cam shaft phasing by +/- 25 degrees. Happy?

[Tenacious G]

Originally posted by myeverlovinsir
VTC CAN advance or retard the intake cam shaft phasing by +/- 25 degrees. Happy?

hmm ... interesting. hondata's site only mentions the VTC's ability to advance timing by as much as 50*. i wonder why they left the retarding ability out.

EDIT: just read about the VTC briefly on Honda's Web site. i stand corrected. sorry for the confusion.

[myeverlovinsir]

http://asia.vtec.net/article/k20a/11_04.gif

Check this link for more detail...click (http://asia.vtec.net/article/k20a/)

[sniperSI]

Originally posted by Tenacious G
hmm ... interesting. hondata's site only mentions the VTC's ability to advance timing by as much as 50*. i wonder why they left the retarding ability out.

EDIT: just read about the VTC briefly on Honda's Web site. i stand corrected. sorry for the confusion.

Not much point in hondata retarding the timing.


Someone give me thier hondata ecu thanks.

[myeverlovinsir]

By swirling back some of the exhaust air back into the combustion chamber, combustion temperature is lowered, and NOx output is reduced.
This is why honda uses retard timing...for cleaner emissions and improved fuel efficiency.

[Tenacious G]

Originally posted by sniperSI
Not much point in hondata retarding the timing.


Someone give me thier hondata ecu thanks.

i'm talking about their K20 info page, not their reflash info. i realize there's no advantage for the reflash to retard timing.

[SiGuy]

It actually does advance do both. Quote from Honda-. "VTC is a hydraulically operated system that controls the phasing, or timing of the chain driven camshaft, advancing or retarding it during the intake cycle. This results in more precise control over the timing of the valves, relative to crankshaft position. During low rpm operation, intake air is drawn almost exclusivly through the primary intake valve, therby creating a strong swirl effect to maximize combustion. At higher rpm, the second rocker arm engauges the primary roller, causing both intake valves to open for the same lift and duration, substantially icreasing airflow and boosting performance"
Honda product facts book