a20a3-a20a4

**b8er** · 03-01-2005, 03:40 PM

i did some research and found out what all the a20a all stands for 20 being engine size, a being sohc but i cannot find what the 4 stands for, is there a difference between the a20a4 and a20a3, im sure this has been asked before but i had always thought my car was an a20a3 and when i was working on it today my buddy who has an 87 lude asked me how to determine the engine code and so i wipped off the little flat spot and it said a20a4, so i was a little shocked and i dont know what the difference is, can anybody help, is there a massive difference? or is it just made in different years, thanx for any info

**88accordhb** · 03-01-2005, 03:58 PM

well a is the series, and it doesn't nesecarilly mean sohc, however in this case, a-series only had sohc. d-series had both sohc and dohc versions. the 20 is for displacement, 2.0 liter. i don't know exactly wat the different between the 4 and 3 is. but they're just clasification numbers. i think only you guys with the edm and adm had the a20a4, uhh canada? iono. wouldn't differ much, you can preplace most of your engine parts with usdm a20a3 parts.

**b8er** · 03-01-2005, 04:29 PM

yea i know about the letter designations i was just wanted to know if there was a differnce between the 3 and 4

**88accordhb** · 03-01-2005, 04:59 PM

i'm gonna say...........

.......maybe?

**phrenology** · 03-01-2005, 05:21 PM

Originally Posted by b8er

yea i know about the letter designations i was just wanted to know if there was a differnce between the 3 and 4

Gekko has an A20A4 and he lives in Norway. A20A4s only differed slightly than A20A3s. I think they were offered in the EDM cars only but if you live in Canada and have one than that proves the previous statement wrong. The emissions are different and they have a bit more hp but less torque because of the lift on cam. I have all the data on file somewhere. There's really not that big of a difference. I am debating a cam trade with Gekko for the A20A4.

**smufguy** · 03-02-2005, 12:22 AM

A20A1, A2, A3 and A4 are revision numbers designated for motor injection type (a1 and A2 being carb, a3 and a4 being efis). also, a3 and a4 came with two different emission standards just like the a1 and a2. so basically, the last number u see is just a revision number of the motor and its emission and also designated which countries that motor and the emission system was sold as a combination.

**McNick** · 03-02-2005, 03:45 AM

A4 has no emission. No EGR, other camshaft lobes and so on.

**snow_man_20** · 03-02-2005, 04:07 AM

I think the A4 also has a little more HP too, not much but some.

**McNick** · 03-02-2005, 04:27 AM

Originally Posted by snow_man_20

I think the A4 also has a little more HP too, not much but some.

Yes. I think because of lobe profile.
A3 opens intake valves one after other to screw the af-mixture in cylinder.
A4 opens both intake together.

**b8er** · 03-02-2005, 11:30 PM

alright thanx for all the info guys

**thegreatdane** · 03-03-2005, 08:42 AM

A20A4 has 122hp. No matter what year the engine is. Unlike the A20A3 which only had ~115hp before '88.
In europe we have both A20A4 and A20A3's but mostly it's A20A4's.
As said, A20A4 is completely without emissions. A20A4 compression ratio is 9,4:1 throughout all years.

**smufguy** · 03-03-2005, 10:22 AM

thegreatdane: A20A4 has 122hp?? A20A3 has 120hp and 122 ft-lbs of torque (everyone gets that twisted).

also, A20A1 was 98hp, 108ft-lbs, 9.1:1 cr (86-89)
A20A3, 120hp, 122ft-lbs, 9.3:1cr, 88-89
A20A3 (also called as BT i guess), was 8.8cr and was 86-87.

the emissions on the 86-87 and 88-89 are also different since the 86-87 used single O2 sensor while the 88-89 used two O2s. These are just minor external parts out of the engine, but if you looked at the engine itself, ie the block and the head, they are identical themselves as in either of them would bolt among each other, but stuff like pistons, cams and valves were just different.

**b8er** · 03-05-2005, 11:44 PM

just outta curriousity whick motor would you guys like to have more, the a20a3 or the a20a4?

also was there alot of a20a4's build for the canadia cars? i know mentioned above was that the a20a4 is pretty usual in germany but i wasnt sure about in canada or the states, thanx

***2drSE-i*** · 03-06-2005, 11:06 AM

well, if i had emmissions tests here, i would say a20a3, but since i dont i dont really know, because the difference is only 2 horsepower, and no1 posted the difference in torque, just said it went down........i would have to say a20a3

**rjudgey** · 03-08-2005, 04:23 AM

The A4 has better Rod bolts and water oil cooler on the back, also windage tray in sump but most 3G accords come with those alhtough earlier engines from ET series and BT series didn't a later mod.