Can you upgrade your cams on the stock ECU map?

[vile]

Eric can you please keep threads on topic as these post have no relevance to the OP.
If you want a thread on these posts you posted please start a new thread in the correct section.

 

[jjmartin349571]

Eric, I don't think the point of 'you could get a faster car for x amount rather than spend x amount of money on upgrading y on your current one' is a particularly valid one - everyone on this forum could sell their car and use the money to buy something faster. I paid £650 for my Xsara, same as I paid for my Prelude. If I wanted my Xsara to go faster, I wouldn't just sell it and get another Prelude, you must know it's a more complex decision than that.

We're all here because we love our Accords and when it comes down to it we'd probably rather spend money making our Accords faster rather than chopping them in for something else. As for cams, they're a popular upgrade on pretty much any car - on the H series you can get decent gains from upgraded cams, it's a popular mod with the Prelude crowd.

 

[freddofrog]

When I have all the data, I'll do some sine graphs showing the difference between the stock and uprated cams.

One question that I have, is this ....

On the K engiens, does anyone know how far the ECU can alter the phase of the inlet cam on the VTC ?
Does it uses both air-flow and rpm to calculate ?

Also, once the high-lift cam has been engaged, what happens to the VTC ?

 

[Stevearcade]

On the K engiens, does anyone know how far the ECU can alter the phase of the inlet cam on the VTC ?
Does it uses both air-flow and rpm to calculate ?

I don't know, but there might some clues in this?

Or perhaps this vid:

There's a locking pin that in some circumstances locks the VTC in position. I wonder if that means during VTEC?

 

[freddofrog]

There's a locking pin that in some circumstances locks the VTC in position. I wonder if that means during VTEC?

The vid says it locks it in the retarded position, and unless I'm mistaken, that would be as described in the article where it says "Variation-4 is activated whenever rpm rises and throttle pressure increases, indicating a sense of urgency as conveyed by the driver's right foot. This mode sees the wild(er) cams of the intake camshaft being activated, the engine goes into 16-valve mode now and VTC dynamically varies the intake camshaft to provide optimum intake/exhaust valve overlap for power."

The article also says "Note that lean-burn mode or variation 1 is used only for very light throttle operations"

So it seems to me that the ECU uses throttle position as its main guide to determining the use of the VTC and VTEC solenoids. I always wondered why I wasn't getting good mpg ..... I should use light throtte openings with low pm, not heavy throttle openings with low rpm. For me having grown up with carburretors (they don't lean-burn), this seems counter-intuitive, but now I know how the engine does its lean-burn, I might stand a chance.

Finally, this sentence may have some bearing on the ***le of the thread. "In variation-2, the ECU pops out of lean-burn mode, goes back to 14.7 or 12 to 1 air-fuel ratios and brings the intake/exhaust overlap right up to maximum. This as Honda explains will induce the EGR effect, which makes use of exhaust gases to reduce emissions". So if the camshafts are changed to more aggressive ones, then there may be some aspects of the map that need to be changed to get the AFR out of lean-burn and into stochiometry sooner. I haven't got what I want from Skunk2 yet to be able to confirm or refute this.

Steve, that article is fantastic in its own right btw, I think you (or someone else) linked to it before in another thread ?

 

[Stevearcade]

I think it was me who linked before

 

[freddofrog]

I didn't read that article properly before, but now I know why you were asking about "fuelling" ....tbh I thought that the engine ran at or close to stochiometry all the time

And anyway, I did wonder why and how the i-VTEC was supposed to give good mpg (and doesn't in my personal experience) particularly when up against competing technologies such as FSI.

That diagram of the four operating regions is very good to know.

1. best fuel exonomy: lean-burn
2. fuel exonomy + power
3. optimum low-end torque
4. optimum mid/high-end torque

But the ECU only does two thinngs to the engine
A. switches the direction of the VTC
B. engages the high-lift

The mapping will set the conditions when these happen, as well as AFR and ignition timing of course.

So your question is very pertinent, more precisely "how much change to lobe height, and/or degrees of lobe duration, can be tolerated before the stock ECU map would need to be changed" ?

Answer lies in the "recommended" part of the descriptions for the different K20 camshafts on the Skunk2 website.

 

[freddofrog]

answers are ....

K20A2, K20Z1, K20Z3, K24A2 stage 1, stage 2, stage 3 .... all require aftermarket ECU

K20A3, K24A1, K24A4, K24A8, K24Z1 stage 2 .... aftermarket ECU recommended but not required

notes
1. "stage" is the amount of increase in HP, so each "stage" will be more "aggressive"
2. all the camshafts for K engines require uprated valve springs
3. the camshaft specs for K20A2 etc are more complex than for K20A3 etc, so IMO it is the intricacy across the lobes that will determine the answer to the question.

I just wish that the K24A3 was listed so that we knew where we stood on that one regarding ECU

.

 

[freddofrog]

oops wrong button

 

[freddofrog]

I called Skunk2 on Skype in the evening (8 hours time difference), was on the phone to a chap there for about 20 mins (cost me less than a quid).

A fascintating conversation, seems I'm right. Their stage 1 camhafts have slight increases in lift and duration but not overlap, stage 2 more increase in lift and duration and some increase in overlap, stage 3 even more than stage 2. He said that the lift on stage 3 is so aggressive, that pistons with a more concave crown would be a good idea. He said that there are two main types of head for K-series engine: the 3-stage VTEC and the 2-stage VTEC. The camshafts are different, and the 2-stage VTEC heads are on engines made more for economy than power (sounds like the K24A3 engine).

He said that it takes their mechanics 15 minutes to change both camshafts on an engine. He said that valve springs can be changed without removing the head but you need a special type of spring compressor, and the procedure is to move the piston to TDC then slightly presurise with an airline through the spark plug hole to keep the valves up (FWIW I've only ever done valve springs myself 35 years ago with the head removed).

Regarding ECU, he said that whilst it might be possible to fit a stage 1 camshaft without a remap, it's best to get an aftermarket ECU anyway before doing any of this. He also agreed when I said that the K20 was probably a better engine to mod than the K24, indeed he said that there is a new Civic in the USA with a K24, which everyone was excited about, but it's a disappointment. He also agreed when I said that the K20 head can pass higher volumes of air than the K24 head (I read that on this forum). He said that it is possible to fit a K20 head to a K24 block with minor mods to fitments, but it would be a good idea to change pistons (concave etc) while one was at it. He also agreed that the Hondata ECU's are an easier job on the K20 than the K24.

So, I would say to anyone thinking of buying a petrol Accord with a K-series engine
1. if you think that you will never mod the engine, go for the K24
2. if you think that you will mod the engine in the future, go for the K20

Basically the K20 is easier to mod and has the ability to give much higher HP than the K24.
But to answer the question Steve ...yes, but best to get an aftermarket ECU first (and I'm 100% up for that, I'd love to find a piggy-back ECU and wire it in myself)

Anyone want to swap a K24 for a K20 btw :lol:


edit: btw I think the pistons can be changed on these engines with the block in the car, and fortunately these blocks have dry-liners so head removal will be straightforward ... the idea of removing the head from a wet-liner block would scare me to death h34r:

 

[Stevearcade]

Wow! Nice work Brian. This is very interesting, and kind of what I'd come to think. The ECU first whatever the state of play. I've read a lot about K20/K24 hybrid frankenstein jobs. Lots of people do this with all over the internet for very good power gain. I'm not really in the mind for modding engine internals myself. Like I said, I just stumbled upon these which have the sales pitch of being a straight forward and easy direct replacement for the stock cams. But as I suspected it's probably not that simple and probably not worth the hassle and/or cost. I'll stick with a remap alone when I can either get to XO or if/when Fahad and/or Adam get the right tools for the early K24 ECU.

Thanks though Brian, much appreciated. And so when are you getting some stage 2 cams, springs, pistons, K20 head and Hondata ECU reflash? :lol:

 

[freddofrog]

Haha I'd love to do it, really would, but I'll settle for the pipe-dream in the meantime.

btw I didn't know that you had that article in your knowledge base, so my initial posts were somewhat OTT.

I really am glad that you stumbled onto that Malaysian site offering Skunk2 camshafts and then later revealed that article (and the vid), with research it completes the jigsaw puzzle of the i-VTEC engine. I'd love to live in California, it would be so much easier and cheaper to do engine modding, it's too cold here and cars and parts are too expensive.

 

[toffee_pie]

and besides, with draconian road limits, anything over 90mph and you are considered a danger to society and would be summoned before magistrates for being naughty.


not that i condone speeding but seems a bit pointless to even have a fast car now and not be able to use it, hell even a stock CL9 just rumbles along most of the time here to keep within limits.

 

[Stevearcade]

Indeed Eric, but for me, it's not about going over the speed limits, just how quickly you can reach them in the first instance (that and being an unassuming Honda that gives bullish german car drivers a scare when they try to rag past you on the motorway, but can't :lol: )

 

[damo10000]

Hi im new to this forum,

My question is i have a honda accord with a k24a8 and ive sourced a camshaft thats suitable for a k24a4 but it doesnt say if its suitable for a k24a8.

I realise the k24a4 to a8 has some enhancements but mostly were the intake resonator chamber attached to the intake manifold, the drive by wire and maybe more agressive camshaft.

I can get a stage 2 from brian crower is it likely this will work and if so do i need a aftermarket ecu. it will only seeing max revs of 6500rpm.

My other question is if its not going to rev higher than standard redline could i get away with std springs.

Its not very often if gets driven above 4000rpm but the occassional burst to redline.

My main concern is the piston to valve interference but based on the specs its 284 duration and .410 lift versus 270 and about .370 lift in " so its a mild camshaft.

down the track I'm going to put headers, I already have intake and maybe invest in a ktuner or kpro but I don't want to invest a lot.

My goal is to really just get about 20% more power and 10% more torque as its a daily driver/

 

[freddofrog]

I had to look up Lalor to see where you are, Melbourne it seems

I suspect that your Accord is an import from the US, so it's not the same car as the JDM/EU Accord, which is why you're talking abut K24A4 and K24A8 engines.

If you look here ---> https://en.wikipedia.org/wiki/Honda_K_engine#K24A K24A4/K24A8 are very different from the K24A3 that we have here in the UK.

Since the compression ratios on K24A4/K24A8 are the same, I would think that camshafts for K24A4 and K24A8 are interchangeable (but don't take my word for that, I'm only going on compression ratios in wikipedia). But I'm puzzled why you want to put a camshaft for a K24A4 into a K24A8, isn't there already a difference between the stock camshafts on those engines ?

Regarding valve springs, you might get away with it, but surely the supplier of the camshaft will know (just as I found out about Skunk2 cams by calling Skunk2 in the US).

 

[exec]

I called Skunk2 on Skype in the evening (8 hours time difference), was on the phone to a chap there for about 20 mins (cost me less than a quid).

A fascintating conversation, seems I'm right. Their stage 1 camhafts have slight increases in lift and duration but not overlap, stage 2 more increase in lift and duration and some increase in overlap, stage 3 even more than stage 2. He said that the lift on stage 3 is so aggressive, that pistons with a more concave crown would be a good idea. He said that there are two main types of head for K-series engine: the 3-stage VTEC and the 2-stage VTEC. The camshafts are different, and the 2-stage VTEC heads are on engines made more for economy than power (sounds like the K24A3 engine).

He said that it takes their mechanics 15 minutes to change both camshafts on an engine. He said that valve springs can be changed without removing the head but you need a special type of spring compressor, and the procedure is to move the piston to TDC then slightly presurise with an airline through the spark plug hole to keep the valves up (FWIW I've only ever done valve springs myself 35 years ago with the head removed).

Regarding ECU, he said that whilst it might be possible to fit a stage 1 camshaft without a remap, it's best to get an aftermarket ECU anyway before doing any of this. He also agreed when I said that the K20 was probably a better engine to mod than the K24, indeed he said that there is a new Civic in the USA with a K24, which everyone was excited about, but it's a disappointment. He also agreed when I said that the K20 head can pass higher volumes of air than the K24 head (I read that on this forum). He said that it is possible to fit a K20 head to a K24 block with minor mods to fitments, but it would be a good idea to change pistons (concave etc) while one was at it. He also agreed that the Hondata ECU's are an easier job on the K20 than the K24.

So, I would say to anyone thinking of buying a petrol Accord with a K-series engine
1. if you think that you will never mod the engine, go for the K24
2. if you think that you will mod the engine in the future, go for the K20

Basically the K20 is easier to mod and has the ability to give much higher HP than the K24.
But to answer the question Steve ...yes, but best to get an aftermarket ECU first (and I'm 100% up for that, I'd love to find a piggy-back ECU and wire it in myself)

Anyone want to swap a K24 for a K20 btw

edit: btw I think the pistons can be changed on these engines with the block in the car, and fortunately these blocks have dry-liners so head removal will be straightforward ... the idea of removing the head from a wet-liner block would scare me to death

The K20 he is referring to will be the K20A found in the Type R's. The standard Accord came with k20a6, which is an economy engine, so you won't get much out of it.

 

[freddofrog]

^ I'm amazed that this thread has had nearly 7,000 views

but that's a good clarification point