Obd 1 p28 ECU from 1992-95 civic ex or si..Is there any difference between ex or si?

[johnmota93]

Hi im shopping for a obd1 p 28 ecu, i just found out there are from civic si and civic ex, is there any difference between the 2 does the si one vtec kick harder? accelerate faster?

I wanna make sure i get the best p28 i thought they only came from civic si

if anyone knows from experience or wutever please give me some advice thanks in advance!

 

[AlaskaB16]

p28 is a p28 (Though now you have me second guessing myself). Only dif is auto or manual which is easy enough to change if you get one or the other. Also, you can chip a few other ecu's into p28's if you cant find the exact ecu you want.

 

[johnmota93]

ok cool yea man im so confused i thought they only came in si's turns out in ex's also? im thinking that too p28 should be the same right i just dont know if the si one has stronger vtec or better acceleration etc?

and now that you mentioned chipping from auto to manuel that same guy on craigslist does that for 10$ i dont know if you think i should do the conversion with him cuz auto p28s are way cheaper than manuel p28 for some reason?

 

[AlaskaB16]

Changing from auto to manual takes all of 2 minutes. $10... eh.. Im not mad at that. Anything with a d16 vtec should run a p28 and there should be zero difference between cars that came with them as far as performance goes. If there was, you'd see a lot more people asking for a certain p28 and you dont.

 

[johnmota93]

ok yea makes sense i already found a good p28 , its coded p28-A00 , its manuel i know by the first zero, its virgin no chips or mods , and the last zero i believe means its the first like firmware version i believe its off a 92-93 civic ex or si hes giving it to me for 80$ pretty good i think at least here in l.a those suckers go for 120-160 lol good thing is its 5 speed so i dont have to mess with the ecu...

i dont think it matters performance wise either right since its A00 which means 92-93 civic compared to A02 for example which i believe is 94-95 civic they should still be the same right?

that sounds like a good ecu right?

thanks for all your help alaska by the way do you have a d series or a b series?

 

[AlaskaB16]

I have multiple d, b, and k series and have a line on a h ... stick around and you'll see. That ecu should work though.

 

[boosted to 26ps]

Here ya go...

P28 : 92-95 OBD-1 Civic Si/Ex
EX AUTOMATIC:
37820-P28-A51
37820-P28-L51

EX MANUAL:
37820-P28-A01

Si MANUAL:

37820-P28-A01
37820-P28-L01

differences between ex and si....no....both mapped identical since they both used the same engine

 

[johnmota93]

Damn! Sik!! i saw ur pics, You got another ride or you just swap through em in your red ej1?Sik rims btw rota slipstreams right? im waiting for my tax refund to pik up some of those...cant decide between white or black tho

yea i got it yesterday good come up for 80 i see em on ebay for 120-150 fuk that
i opened it up made sure it wasnt a fake or chiped n modded so it should work fine im just waiting for my jumper harness lol

I have multiple d, b, and k series and have a line on a h ... stick around and you'll see. That ecu should work though.

 

[johnmota93]

Cool thanks man i piked one up yesterday,
says 37820-P28-A00 so i know its a usdm 5 speed last zero means its like first version of it
this one is labeled as a 92 civic dont know if it came from si or ex but yea it dosent matter just confused me for a sec, thanks for that list helps alot!

Here ya go...

P28 : 92-95 OBD-1 Civic Si/Ex
EX AUTOMATIC:
37820-P28-A51
37820-P28-L51

EX MANUAL:
37820-P28-A01

Si MANUAL:

37820-P28-A01
37820-P28-L01

differences between ex and si....no....both mapped identical since they both used the same engine

 

[boosted to 26ps]

Cool thanks man i piked one up yesterday,
says 37820-P28-A00 so i know its a usdm 5 speed last zero means its like first version of it
this one is labeled as a 92 civic dont know if it came from si or ex but yea it dosent matter just confused me for a sec, thanks for that list helps alot!

yes the last set of numbers is the revision number.....first being the honda part number....second being which model of car it is from....

as your referance to the last three coming from a 94-95 civic...not entirely true. the revision of the ecu could of took place sometime in 93...sooo thus some 93 civics will have that and some wont. it all depends on when honda decided to update the ecu board. and it could go to a09....basically says how many times the ecu board was revised by the company

 

[johnmota93]

ok yea so mine is pretty much unrevised A00 its the first ecu boards they launched out with right?
shouldnt be any difference in performance between mine and a A02 for example right?

nd no on mine its labeled 92 civic since its A00 im pretty sure it is off a 92-93 civic

yes the last set of numbers is the revision number.....first being the honda part number....second being which model of car it is from....

as your referance to the last three coming from a 94-95 civic...not entirely true. the revision of the ecu could of took place sometime in 93...sooo thus some 93 civics will have that and some wont. it all depends on when honda decided to update the ecu board. and it could go to a09....basically says how many times the ecu board was revised by the company

 

[boosted to 26ps]

ok yea so mine is pretty much unrevised A00 its the first ecu boards they launched out with right?
shouldnt be any difference in performance between mine and a A02 for example right?

nd no on mine its labeled 92 civic since its A00 im pretty sure it is off a 92-93 civic

yup pretty much right....fist year of the board for that model

 

[johnmota93]

ok cool just needed to confirm it...

by the way since the p28 i got is virgin do you know when the v-tec kicks in on this p28?
i think i heard it was at 4,800 or 5,500 rpms?
not sure im just wondering?

yup pretty much right....fist year of the board for that model

 

[boosted to 26ps]

ok cool just needed to confirm it...

by the way since the p28 i got is virgin do you know when the v-tec kicks in on this p28?
i think i heard it was at 4,800 or 5,500 rpms?
not sure im just wondering?

anywhere in between of that range....my stock y8 switches over at like 5300 i think

 

[emerican]

y8 is 5,500 if i remember correctly

 

[boosted to 26ps]

y8 is 5,500 if i remember correctly

yeah...im not really paying much attention to the guage.

 

[johnmota93]

ok cuz what controls the when the vtec engages the ECU right?

The y8 comes with a p2p right? does that vtec engage different than the p28?

ima start a new thread with this topic just so i can be sure lol

 

[boosted to 26ps]

VTEC engagement needs 4 readings to the ECU before the ECU will switch to VTEC......

engine speed, above 4800 rpm (4800 WOT, 5200 no load)
engine load, MAP and TPS readings
vehicle speed, above 13 mph
engine coolant, above 140F

Once those 4 parameters are met, then the ECU will send the signal to engage VTEC. If the oil pressure then falls below 50-55 psi, VTEC kicks out and you get CEL 22.

yup p2p...and no. basically the ecu tells the solenoid to lock the secondary rockers so it rides on the secondary lobe on the camshaft on dohc only.....single slams is the same thing except it only works on the intake valves i believe

 

[johnmota93]

damn my bad i just noticed i didnt hit the reply button lol

ok so what controls when the vtec engages and how much it engages ? The ecu right?

cuz i know the y8 comes stock with the p2p ecu , thats the one i have right now,
but i heard the p28 ecu is the best ecu for sohc, because vtec engages earlier and engages harder ? im not sure tho thats just what i heard from a friend ?

ima start a new thread maybe someone knows for sure and could clear it up for me

cuz i dont know whats the difference between the p2p and p28 ecu? i just heard the p28 is better but for what reason?

thanks either way you guys for helping me out on this thread

 

[johnmota93]

o wait my computer still had the old page loaded haha damn sorry about that you guys