5th gen engine in 6th gen

[168sierra]

I am considering installing a 5th gen (2000) engine into a 6th gen (2003) to take advantage of the power of the 5th gen engine and gear driven cams (love the sound) and the handling of the 6th gen with an RC51 front end.

Has anyone used the 6th gen FI on a 5th gen motor? From what I have read, the throttle bodies bolt on. I was palnning to use the 330 ohm resistors to bypass the O2 sensors and run a catless header. I am thinking of trying to reflash the ECU with a 5 th gen fuel map. This should be close but will probably need some fine tuning.

Does anyone have any experience with this? I can't be the only one who wants this combination.

Pics to follow

[vfrcapn]

Someone in the UK did the 5G motor in to the 6G bike swap but it was a pia iirc. I'd stick with the 5G throttle bodies and ECU if you try it. The 6G stuff is set up for the VTEC...

[Ryanme17]

Don't worry about the throttle bodies and ECU. Keep those both 5th gen. The ECU will HAVE to be 5th gen. The difficulties will all be wiring-harness related.

[Cogswell]

To me this is the holy grail of projects . . . for my money anyone that pulls this off goes in the VFR hall of fame. I don't have it 1st hand, but last year was told that the guy's name that did this swap is Mark J. Harris and had been posted on the VFR Club site in the UK - but it's since been purged. The main fitment stumbling block is that the front valve cover interferes with the frame and has to be narrowed or cut down to clear. 5th & 6thg valve covers do not interchange. There are probably other minor fitment issues you'd only find out by trying it. Is your VTEC ABS? I have not studied the book to see if the ABS is controlled from the same ECU or has a separate control unit. It sounds like anything but plug and play. Can't wait to see the pics.

[kaldek]

If I hear one more bloke tell me that the 5th-gen engine is more powerful I will puke all over my keyboard.

BOLLOCKS I say. There's stuff-all difference in power between the two.

[Vee-Ef-Ar]

Just buy a 5thGen.

I love my 98 engine.

It's virtually a maintainence-free volcanic lump of linear V4power.

Do you know it sings to me when we're alone.

Kaldek is right though... he will puke.

[WERA910]

Kaldek get a bag.

I've put 70k miles on two different '98 fifth gen VFR's... so when I got my 6th gen and started to ride it my big question was "Where's the F'n power"... I really thought I had something wrong with the bike, until T-mac when I got to do roll-on accelleration tests with KPerham and Baileyrock... Baileyrock's bike and mine were just about even, although he had the slight advantage from better gearing. Perham would roll away from us like it had another 200ccs.

Everytime I hear the click of my cam chain tensioner on cold start up, I want to swap in a 5th gen engine... when you combine the power with the gear drive noise... and eliminate the dreaded tensioners... sounds like a win/win/win. Now, will I actually do it? Um, probably not unless I blow this one up for some reason.... which isn't too likely.

[Veefer800Canuck]

Yes, it has been done, and quite sucessfully.

Cogswell is right about the valve covers, they need to be cut and modified to fit the 6th gen chassis.

Mark J Harris on the UK site wound up using all the 6th gen wiring, ECU and the throttle bodies/injectors.

He added a power commander to correct the fuelling below 7k RPM where the VTEC ECU would normally "think" it's in 2-valve operation.

Also, IIRC, he fitted some O2 eliminators, which is standard stuff with the PC.

Bike ran great, it was a lot of work, definetly not plug and play.

If one could re-pin the ECU connectors, assuming they were physically the same (though I don't know), AND, if the valve covers were interchangeable (which they are not), then the whole swap would be a lot easier.

Good luck to you sir, and yes, take lots of pics.

[Ryanme17]

Is your VTEC ABS? I have not studied the book to see if the ABS is controlled from the same ECU or has a separate control unit. It sounds like anything but plug and play.

The ABS controller is under the side panels. Not sure how you'd get it to integrate with a 5th gen ECU, or if it even needs to, though.

If I hear one more bloke tell me that the 5th-gen engine is more powerful I will puke all over my keyboard.

BOLLOCKS I say. There's stuff-all difference in power between the two.

I've looked at a lot of Dyno charts on here and I agree, but we're not going to convince anyone otherwise.

Yes, it has been done, and quite sucessfully.

Mark J Harris on the UK site wound up using all the 6th gen wiring, ECU and the throttle bodies/injectors.

He added a power commander to correct the fuelling below 7k RPM where the VTEC ECU would normally "think" it's in 2-valve operation.

So timing is close enough between the two engines below 7k RPM? I guess I just ASSumed it would be noticeably different.

[168sierra]

Though there may not be much difference between 5th and 6th gen in terms of total power the difference is in the power curves at lower rpms. I always feel like my 6th gen is lugging when it is below 4,000rpm. It does not feel like it has as much low end pull as my 83' VF750F with the 360 crank.

I would like to use the 6th gen Fi but if I have to use 5th gen and make my own wiring harness that's ok. I was an electrician and the wiring harness fabrication is not overly complicated.

I know this may not be the most practical project but I think I will really like the end result. If only I could do the 5th gen engine with a360 crank, but that is alittle too involved!

[168sierra]

My bike is not ABS so that is one lessthing to worry about. If it was I would not convert it to an RC51 frront end.

Kevin, WERA910 said you used VFR1200 handlebars on your RC51 front end conversion. Did they bolt on with no mods? Do you like them?

[Baileyrock]

Kaldek get a bag.

I've put 70k miles on two different '98 fifth gen VFR's... so when I got my 6th gen and started to ride it my big question was "Where's the F'n power"... I really thought I had something wrong with the bike, until T-mac when I got to do roll-on accelleration tests with KPerham and Baileyrock... Baileyrock's bike and mine were just about even, although he had the slight advantage from better gearing. Perham would roll away from us like it had another 200ccs.

I doubt that if a 5th gen & 6th gen 800cc engines were set on a dyno with the same exhaust(43mm vs 41mm), same mapping(not the super Lean Vtec mapping) and gearing that you would see any noticeable difference in power or torque. Also you and your Vtec were probably carrying an extra 100 lbs vs Kev on the 5th gen.

When I went from my 2000 VFR ( smaller exhaust, etc.) to my 02 the only difference I felt was much more capable chassis.

They all great bike and no doubt that the larger headers and fatter fueling of the 98-99 Should make more/better power, but you need to compare apples to apples my friend.

BR

[toro1]

Red is 6th-gen, green is 5th-gen. 5th-gen has a better cam drive and seamless power delivery, 6th-gen has a beefier clutch and an almost (but not quite) seamless power delivery. 6th-gen makes more power than the 5th-gen across the board (except between 5500-6500 rpm), but the heavier weight negates some of that extra performance. You can't lose either way, but swapping engines would not be worth the effort in my opinion.

[KevCarver]

My bike is not ABS so that is one lessthing to worry about. If it was I would not convert it to an RC51 frront end.

Kevin, WERA910 said you used VFR1200 handlebars on your RC51 front end conversion. Did they bolt on with no mods? Do you like them?

Yes, and yes. If by no modification you mean to the bars or the forks, or general cockpit area. Of course the fork swap was a slight modification... Lol

I used stock switch pods and RC51 clutch and brake masters.

Unless you already have the Y2K engine, try to source a '98-'99 and wiring harness. You don't need any of the extra stuff associated with the "updated" version of the engine or throttle bodies. Just my opinion, of course.

And for Bailey, yes we should have swapped again and done a roll on with each others bikes. But I think 100# difference is a bit of an exaggeration! Plus I had the GIVI trunk, and it wasn't even close really! My bike is stock gearing, de-flappered, de-paired, no PC, and the Staintune. Dyno'ed years ago at a hair under 98. Maybe graphs don't illustrate the difference, but I think mine has better low end pull than either VTec I rode. And still goes very strong when the powerband starts to kick in without the valve changeover gimmick of the VTec.

[Cogswell]

The merits of the power of one vs the other aside, I have little doubt that if someone pulled up at a VFRD meet on a 6th gen with that GDC whine emanating from under the plastic, everyone would be saying WTF is THAT? I'm pretty sure it would be the bike everyone would want to take a closer look at. Would it be practical financially? Probably not. Could I better spend my time doing something else? Most likely. Do I want one? Absolutely.

[Guest]

Red is 6th-gen, green is 5th-gen. 5th-gen has a better cam drive and seamless power delivery, 6th-gen has a beefier clutch and an almost (but not quite) seamless power delivery. 6th-gen makes more power than the 5th-gen across the board (except between 5500-6500 rpm), but the heavier weight negates some of that extra performance. You can't lose either way, but swapping engines would not be worth the effort in my opinion.

...Those are blown hp; are the numbers relative NA? I would think the only advantage would be the gear driven cams...

[WERA910]

wrecked 5th gen acquired... here we go!

[WERA910]

Mark,

Read this post from the man who done it... he talks about modifying the valve covers for the coil packs.

http://www.bikersoracle.com/vfr/forum/showthread.php?p=1150667#post1150667

[Baileyrock]

wrecked 5th gen acquired... here we go!

I was looking at that one, but he wanted too much IMO.

PM me what you got it for.

[Metallican525]

[mello dude]

Fun thread ---

* *

[Veefer800Canuck]

Mark,

Read this post from the man who done it... he talks about modifying the valve covers for the coil packs.

http://www.bikersoracle.com/vfr/forum/showthread.php?p=1150667#post1150667

But if you have an entire 5th gen, you might not use the 6th gen ECU, injection system or ignition system.

In that case, maybe the valve covers might not need to be modified?

[168sierra]

Mark,

Read this post from the man who done it... he talks about modifying the valve covers for the coil packs.

http://www.bikersoracle.com/vfr/forum/showthread.php?p=1150667#post1150667

But if you have an entire 5th gen, you might not use the 6th gen ECU, injection system or ignition system.

In that case, maybe the valve covers might not need to be modified?

[168sierra]

Mark,

Read this post from the man who done it... he talks about modifying the valve covers for the coil packs.

http://www.bikersoracle.com/vfr/forum/showthread.php?p=1150667#post1150667

But if you have an entire 5th gen, you might not use the 6th gen ECU, injection system or ignition system.

In that case, maybe the valve covers might not need to be modified?

I can't wait to get home to look at it and start figuring out how to modify the valve covers. I want to hear the gear whine.

[flyguyeddy]

my perfect 6 gen: 6 gen frame, 5 gen engine, 929 swingarm, 929 forks, rc211v style bodywork and exhaust. Beautiful!

[Dutchy]

Green 5th Gen

Orange 6th Gen