Why is the DOHC VTEC F20B a 'destroked' H22A?

[blizzard335]

Just a question. Why is the DOHC VTEC F20B referred to as a destroked H22A?

The F20B has an 85 x 88 (bore x stroke), while the H22A is 87 x 90.7.

The SOHC VTEC F20B shares similar 85 x 88 dimensions.

So, why is the F20B said to be destroked from the H22A? it shares nothing in common, dimension wise with teh H22A.

It does, share the same bore x stroke with it's lesser SOHC VTEC sibling, and going back in time, similar 85 x 88 dimensions with the SOHC NON-VTEC F20B in the CD4 and the F20A in the CB3/4.

[Flatline]

So your saying it's basically an H head on a SOHC F20B block?

I would think it's a destroked H22 because it has less stroke, thus less overall volume. But still retains the Head of the H22 and the peformance that the H22 brings.

I guess it could be marketing. Who wants a better version of a lesser engine over a smaller version of a better engine. while still retaining most of the performance of the better engine.


Or im tired and am talking out of my ass.

[blizzard335]

So your saying it's basically an H head on a SOHC F20B block?

I would think it's a destroked H22 because it has less stroke, thus less overall volume. But still retains the Head of the H22 and the peformance that the H22 brings.

I guess it could be marketing. Who wants a better version of a lesser engine over a smaller version of a better engine. while still retaining most of the performance of the better engine.


Or im tired and am talking out of my ass.

I dunno. the pistons are different, since the bore is different.

destroked would mean, shorter stroke, right, or has my english gone bad?

because I read somewhere on here, that the F20B DOHC VTEC was conceived so that Honda could compete in the sub 2.0L class of touring car racing..

If true, then why did Honda axe the SiR-T (manual LSD 200PS) variant in 2000 and introduce the H22A 220PS CL1 EuroR?

Shouldnt it be that the F20B DOHC VTEC was a more powerful version of the SOHC F20B? they do share the same block, but the DOHC runs higher 11:0 compression.

if the F20B was a destroked H22A, shouldnt it be named H20A/H20B?

Thoughts to ponder

I dunno, Im hungry

[bagoon316]

i agree with blizz, its shorter stroke and smaller bore, and the heads arent identical. they are similar heads, but not the same. i think its a diff engine entirely, that some parts are shared with h22.

stating an f20a dohc non vtec is a destroked f22b dohc is a worthy statement. since all parts are the same except the crank/rod combo.

[bagoon316]

if you put the f20b crank/rods into an h22a4 then that would be classified as a destroked h22. even still it would be around a 2.1L and not a 2.0L though.

[gloryaccordy]

I. Don't. Know. I imagine it had to do w/displacement taxes too, but that deosn't explain why they axed the F20B

[bagoon316]

the f20b was created iirc for scca sub 2.0L class or something like that.

[blizzard335]

i agree with blizz, its shorter stroke and smaller bore, and the heads arent identical. they are similar heads, but not the same. i think its a diff engine entirely, that some parts are shared with h22.

stating an f20a dohc non vtec is a destroked f22b dohc is a worthy statement. since all parts are the same except the crank/rod combo.

The heads are similar, there's a guy here who thought that if he swapped over an SiR-T head with his BB4 sourced H22A, he would gain more power. He did, but I'd dare say that the cams made the difference, not the head.

And yes, the F20A/F20B (SOHC NON-VTEC) is a destroked F22A/F22B ( or which way you view it ) since the bore is similar, but stroke length is different.

[blizzard335]

I. Don't. Know. I imagine it had to do w/displacement taxes too, but that deosn't explain why they axed the F20B

They didnt axe teh F20B DOHC VTEC when they introduced the EuroR, just the manual, 200PS SiR-T version.

the SiR was still available alongside the EuroR, VTS and VTE

the f20b was created iirc for scca sub 2.0L class or something like that.

Isnt SCCA American? the F20B wasnt available in the 'States, right? The F20B was available outside of America, in all 3 versions of the 6th gen CF/CG/CH Accord.

[bagoon316]

oh i dunno, it was something with taxes and i thought also some racing sub 2.0L class. maybe not scca, i cant remember though.

right i said they are similar, but definately not the same. h22 valves will fall out of a f20b, i think the valve diams are also diff. not to mention the head bore is 85 like the pistons not 87. so def some differences for sure.

[blizzard335]

oh i dunno, it was something with taxes and i thought also some racing sub 2.0L class. maybe not scca, i cant remember though.

right i said they are similar, but definately not the same. h22 valves will fall out of a f20b, i think the valve diams are also diff. not to mention the head bore is 85 like the pistons not 87. so def some differences for sure.

Awesome thought. Gives me a chance to pop open an F20B head and compare it to an H22A

[bagoon316]

i just remember reading it on HT somewhere about a guy that built his head using h22 parts. i believe his valves dropped, due to the stems being diff. i am almost positive the diams of the face are diff also.

http://www.honda-tech.com/showthread.php?t=1232811

^^ valves are 1mm each smaller compared to h22. the cams def gave his h22 more power, on ur buddies rebuild.

[blizzard335]

i just remember reading it on HT somewhere about a guy that built his head using h22 parts. i believe his valves dropped, due to the stems being diff. i am almost positive the diams of the face are diff also.

http://www.honda-tech.com/showthread.php?t=1232811

^^ valves are 1mm each smaller compared to h22. the cams def gave his h22 more power, on ur buddies rebuild.

Awesome. So, will this smaller valve size be a 'handicap' to the F20B?

[gloryaccordy]

They didnt axe teh F20B DOHC VTEC when they introduced the EuroR, just the manual, 200PS SiR-T version.

the SiR was still available alongside the EuroR, VTS and VTE



Isnt SCCA American? the F20B wasnt available in the 'States, right? The F20B was available outside of America, in all 3 versions of the 6th gen CF/CG/CH Accord.

I think it was more for the BTCC

http://www.supertouring.co.uk/techreg2.html

Engines: A Super Touring racecar must be equipped with a normally aspirated two-litre engine with no more than 6 cylinders. Manufacturers are allowed to select any engine from its range, not necessarily from the homologated car, as long as over 2500 units have been produced in a 12-month period. The engine bore and stroke can be adjusted to meet the 2000cc limit if required, meaning a smaller or larger engine can be selected as a starting point. When fitted to the car, the engine must be located in the same relative position as in the production model (i.e. transverse or longitudinal) however it can be moved within the engine bay as long as no modifications to the engine bay are made.

To limit engine performance and development costs all engines are limited to 8500rpm, which until 1997 was controlled via a mandatory FIA approved electronic rev-limiter. From 1997, the rev-limiter became optional and a newly introduced 'black-box' data recorder became mandatory. The recorder enabled the scrutineers to record the engine revs over a longer period of time and thus check for any anomalies which a simple re-limiter would not pick-up.

In a similar way to F1 teams, the BTCC teams must also submit any Engine Control Units (ECU) to allow the scrutineers (or electronics specialists on behalf of the scrutineers) to check for illegal driver aids. This process was introduced in 1995 following rumours that some teams had introduced 'software driven' traction control within these units thus gaining an advantage.

Other restrictions on engine tuning and components are few, with the exception that the original cylinder block and head must be used, the number and position of cam-shafts must remain the same, and that the crankshaft and con-rods must be made of a ferrous material (i.e. no exotic titanium).

Each car can run a custom made exhaust, but the exit point must be at the rear of the car and the exhaust note must not exceed 110db at 6300rpm. All cars must run on a specific TOCA 'control' unleaded fuel and therefore must also be fitted with an FIA approved catalytic converter.

[bagoon316]

ahh good post glory. i knew it was something.