Im pretty sure the f22 cam gear gets used on the A20 also. from the looks of the header it might hang lower where the down pipe is. Maybe modified so it hugs the oil pan closer.
Header for the B20a3 (PGM-CARB SOHC)
4
Remember, the B20a5 header does not fit on a B20a3 cylinder head. We need a readily available performance header for the B20a3 and other SOHC 3rd gen Prelude cylinder head.
As I was poking around online, I stumbled across this:
OBX RACE EXHAUST HEADER 84-87 HONDA PRELUDE 2.0L A20
http://www.erzperformance.com/ProductDetails.asp?ProductCode=OBXHONDA-14
![]()
I know there are a lot of similarities between the A20 and B20a3 cylinder heads and PGM-CARB setups. It would not surprise me if they are almost identical in a lot of ways.
So I invested $10 in a Felpro exhaust manifold gasket made for a 86 Prelude PGM-CARB.
![]()
Guess what?!?!?!?!
![]()
It fits like the regular B20a3 exhaust manifold gasket. Exact match. Now the only thing to figure out is if the header angle is compatible with the angle the B20a3 sits at. If the angle is right (or close enough), we have a bolt-on performance header options. If the angle is too far out, we could possibly modify it to work.
____________________________
Adjustable Cam Gear too:
Also a side note, here is a F22 adjustable cam gear I bought off eBay for my B20a3 build. I took a gamble on it and found it is an exact fit with the B20a3 cam gear. The only questionable remark I have is regarding the quality of design. The generic eBay cam gears suck.
![]()
In any event, even if this cheap cam gear slips, the B20a3 is a non-interference engine. Meaning under any stock circumstances, a valve will never be able to kiss a piston.
In my particular engine build, I am milling the engine block and head surface down for performance, so I don't know if it will change anything.
As I was poking around online, I stumbled across this:
OBX RACE EXHAUST HEADER 84-87 HONDA PRELUDE 2.0L A20
http://www.erzperformance.com/ProductDetails.asp?ProductCode=OBXHONDA-14
I know there are a lot of similarities between the A20 and B20a3 cylinder heads and PGM-CARB setups. It would not surprise me if they are almost identical in a lot of ways.
So I invested $10 in a Felpro exhaust manifold gasket made for a 86 Prelude PGM-CARB.
Guess what?!?!?!?!
It fits like the regular B20a3 exhaust manifold gasket. Exact match. Now the only thing to figure out is if the header angle is compatible with the angle the B20a3 sits at. If the angle is right (or close enough), we have a bolt-on performance header options. If the angle is too far out, we could possibly modify it to work.
____________________________
Adjustable Cam Gear too:
Also a side note, here is a F22 adjustable cam gear I bought off eBay for my B20a3 build. I took a gamble on it and found it is an exact fit with the B20a3 cam gear. The only questionable remark I have is regarding the quality of design. The generic eBay cam gears suck.
In any event, even if this cheap cam gear slips, the B20a3 is a non-interference engine. Meaning under any stock circumstances, a valve will never be able to kiss a piston.
In my particular engine build, I am milling the engine block and head surface down for performance, so I don't know if it will change anything.
1 - 20 of 46 Posts
PACESETTER 1986-1989 Honda Accord Si 2.0L Performance Exhaust Header #70-1250
http://www.ebay.com/itm/PACESETTER-...t-Header-70-1250-/390377605683#ht_1757wt_1003
![]()
http://www.ebay.com/itm/PACESETTER-...t-Header-70-1250-/390377605683#ht_1757wt_1003
B20A3 to 200bhp
Hey guys was just looking for some B20 info for engine I've just built higher CR ratio, with my own special porting work on head and manifold, 59mm TB, OBX header and 2.25" mandrel bent system, and adjustable cam gears. Hoping to get something decent like 170-180bhp.
But came across this so thought I'd help you clarify some info as I seem to be the ET/ET1/ET2/A18/A20 guru.
ET/A series engine have a shorter stroke and larger bore we typically have 83mm pistons fitted on a performance build or rebore a 1.8l to same 2.0l specs, this when combined with a 1.8l head can give you a seriouslly nice boost in CR ratio. This also means that we have a better stroke to rod ratio than B20A3 enabling much better rpms.
Also the other upside to ET/A over B20A3 is that ET/A crank and rods are extremely light, ET/A is very quick revving engine as it has one of the lightest cranks I've ever seen they have no counterweights, which means they tend to vibrate a bit but the upside to that is very responsive engines!! The Rods are also very light and you can get lighter weight wrist pins as well to help out even more!! Also as for the heads we have round ports on the carb model which really helps with port velocity and fuel atomization as opposed to square and the A20 oval ports are very good for high revs and peak power engines but you get less CR ratio as they're chambers are bigger to compensate for the 9.4:1 CR ratio.
Also the F22 cam gear doesn't work only fits on B20A1 from 86-87 in 2g lude or 86-89 3rd gen Accord B20A1. They typically need 2mm machined off the flange face to fit properly so I'd check to see if your's needs the same too.
As for the exhaust yes our engine is tilted forwards 15 degrees so you'd have to alter the angle of your downpipe but we do the same for B20A5 manifolds that we use for B20A1 in our 2G ludes.
I would think that if you can fit bigger valves and ET/A camshaft grind, increase CR a bit, custom fit some Weber DCOE 45's, port and polish cast header fit 2" downpipes to 2.5" system you could potentially get quite close to 180-190bhp flywheel (no CAT), anymore you'll be needing DOHC head to be honest, and higher CR ratio something around 11:1, although you could potentially fit B21 pistons into B20A3 which could make it interesting!! And that would boost the CR ratio up more easily. B21 bottom B20A3 head with all the above work could well see you upto around 190-200bhp. It would still be slower revving than ET/A series engine but pretty potential torque killer engine with plenty of BHP still. Would certainly be an interesting and different project!!
BTW my latest engine build is A20A3/4 pistons (std size) blue printed with hand gapped oversize rings used from 83mm bore size, block deck just fractionally skimmed to flatten surface, A18 head with 1mm skimmed, head has serious amount of work done completely reshaped ports and increased sizes, 33mm inlet valves, 38mm exhaust valves, bronze guides, uprated double springs, Pipercams 285 degree duration 10mm lift cam grind, twin weber inlet manifold, Modified Twin Weber DCOE 45's, custom downpipe and system 2" downpipes and 2.5" system.
But I've kept stock cast header, and the block is effectively on stock internals although blueprinted so has less frictional losses and tighter ring gaps for higher compression which can be worth a good 3-5bhp alone!! And the ignition system is stock as well apart from advance is disabled as webers hate those. The engine is so efficient that only needs 9 degrees timing advance at idle anymore produces less power.
With the above setup I'm able to achieve 200bhp at 7600rpm and 160lbft at 5500rpm but I would definately get more if a equal length tubular manifold with 1.75" primaries was used, and also if I had a higher CR ratio with some custom forged flat top pistons, and a more aggressive camshaft something like 290 degrees but with 11.5-12mm lift. Would be something like 230-240bhp at 8500rpm and 175lbft at 6500rpm which is something I'd like to work towards over the next year or so, I'm going to change the exhaust manifold first which alone should increase power and peak power to something like 210bhp and peak at 8000rpm instead, then start looking at a block rebuild with forged pistons and higher CR ratio, then have Cat Cams make me a custom grind, or look at Bisi Cam grind (have more lift than mine). Other areas of improvement are replacing my valves with ones with thinner stems they are currently 7mm which is really thick Smeado has found some from another engine which can be used which are only 5.5mm!! so this could potentially help even more!!
Hey guys was just looking for some B20 info for engine I've just built higher CR ratio, with my own special porting work on head and manifold, 59mm TB, OBX header and 2.25" mandrel bent system, and adjustable cam gears. Hoping to get something decent like 170-180bhp.
But came across this so thought I'd help you clarify some info as I seem to be the ET/ET1/ET2/A18/A20 guru.
ET/A series engine have a shorter stroke and larger bore we typically have 83mm pistons fitted on a performance build or rebore a 1.8l to same 2.0l specs, this when combined with a 1.8l head can give you a seriouslly nice boost in CR ratio. This also means that we have a better stroke to rod ratio than B20A3 enabling much better rpms.
Also the other upside to ET/A over B20A3 is that ET/A crank and rods are extremely light, ET/A is very quick revving engine as it has one of the lightest cranks I've ever seen they have no counterweights, which means they tend to vibrate a bit but the upside to that is very responsive engines!! The Rods are also very light and you can get lighter weight wrist pins as well to help out even more!! Also as for the heads we have round ports on the carb model which really helps with port velocity and fuel atomization as opposed to square and the A20 oval ports are very good for high revs and peak power engines but you get less CR ratio as they're chambers are bigger to compensate for the 9.4:1 CR ratio.
Also the F22 cam gear doesn't work only fits on B20A1 from 86-87 in 2g lude or 86-89 3rd gen Accord B20A1. They typically need 2mm machined off the flange face to fit properly so I'd check to see if your's needs the same too.
As for the exhaust yes our engine is tilted forwards 15 degrees so you'd have to alter the angle of your downpipe but we do the same for B20A5 manifolds that we use for B20A1 in our 2G ludes.
I would think that if you can fit bigger valves and ET/A camshaft grind, increase CR a bit, custom fit some Weber DCOE 45's, port and polish cast header fit 2" downpipes to 2.5" system you could potentially get quite close to 180-190bhp flywheel (no CAT), anymore you'll be needing DOHC head to be honest, and higher CR ratio something around 11:1, although you could potentially fit B21 pistons into B20A3 which could make it interesting!! And that would boost the CR ratio up more easily. B21 bottom B20A3 head with all the above work could well see you upto around 190-200bhp. It would still be slower revving than ET/A series engine but pretty potential torque killer engine with plenty of BHP still. Would certainly be an interesting and different project!!
BTW my latest engine build is A20A3/4 pistons (std size) blue printed with hand gapped oversize rings used from 83mm bore size, block deck just fractionally skimmed to flatten surface, A18 head with 1mm skimmed, head has serious amount of work done completely reshaped ports and increased sizes, 33mm inlet valves, 38mm exhaust valves, bronze guides, uprated double springs, Pipercams 285 degree duration 10mm lift cam grind, twin weber inlet manifold, Modified Twin Weber DCOE 45's, custom downpipe and system 2" downpipes and 2.5" system.
But I've kept stock cast header, and the block is effectively on stock internals although blueprinted so has less frictional losses and tighter ring gaps for higher compression which can be worth a good 3-5bhp alone!! And the ignition system is stock as well apart from advance is disabled as webers hate those. The engine is so efficient that only needs 9 degrees timing advance at idle anymore produces less power.
With the above setup I'm able to achieve 200bhp at 7600rpm and 160lbft at 5500rpm but I would definately get more if a equal length tubular manifold with 1.75" primaries was used, and also if I had a higher CR ratio with some custom forged flat top pistons, and a more aggressive camshaft something like 290 degrees but with 11.5-12mm lift. Would be something like 230-240bhp at 8500rpm and 175lbft at 6500rpm which is something I'd like to work towards over the next year or so, I'm going to change the exhaust manifold first which alone should increase power and peak power to something like 210bhp and peak at 8000rpm instead, then start looking at a block rebuild with forged pistons and higher CR ratio, then have Cat Cams make me a custom grind, or look at Bisi Cam grind (have more lift than mine). Other areas of improvement are replacing my valves with ones with thinner stems they are currently 7mm which is really thick Smeado has found some from another engine which can be used which are only 5.5mm!! so this could potentially help even more!!
1 - 20 of 46 Posts
