What is the difference between red top Sr20det and the black top Sr20det for S13 motors?

Me and my friend got into an argument about this.
I'm saying that theres practically NO difference between the two besides the year that they are made.
My friend is sayin that the internals are different. He says that not only the ECU is slightly different, but its got thicker rod bearings than the red top, oil squirters, better oil pump, and other bullcrap that i dont agree on.
I'm just learning about SRs, and he owns a SR.

I know that this topic is posted on a daily bases, but all i see is..."The differnece between the red top and black top is minimal. There are some minor ECU changes, cooling fins on the head (eariler red tops did not have them) and thats basically it....."
http://www.240sxforums.com/forums/ar...p/t-55363.html

 

looks like you answered your own question.
and if its here we go AGAIN, id bet thats its been covered before.

use the internet, its in there somewhere.

 

Every site i go to says that they are the same motors with different valve covers, that's all. But my friend said that the black top has bigger rod bearings, and oil squirter, is that true?

 

there's obviously going to be changes, regardless of top cover color or year even. either is suitable, and if you're looking to make 500+hp, then you'll be addressing those issues anyways with a proper build.

 

Blacktops also have the revised chain tensioner.

 

Check the nico forums, very indepth post about the diffrence's between the 52F and 54C SR's. Which are minor , and no the blacktop doesn't have bigger rod bearings , it does have a bit diffrent pistons and a better oil spray pattern , oil pickup is a little diffrent, and it also has a metal timing chain tensioner vs plastic.

 

There is a difference between the redtop and blacktop....Well, not exactly though.

Production Dates of the S13 SR Motors
PS13 (Silvia) RPS13 (180SX) SR20DET RedTop: Jan 91-Jan 94
RPS13 (180SX) SR20DET BlackTop: Jan 94-May 97

SR20DET S13 Redtop Kouki and Zenki motors
Nissan used two different casts for the Redtop (See the pic below). The later redtop (Kouki) is 100% identical as the BlackTop S13 SRs, besides the color of the valve cover. Basically, if you see heat sink fins on the front of the motor, you have either a Kouki SR RedTop or S13 BlackTop. If it's smooth, you have a Zenki, which is the older SR RedTop.

Pic courtesy of SpeedRacer1 from NicoClub.com

The color of the valve cover of the redtop comes in different reds. It's possible that this indicates the year that the motor was built, like the bright red is 1991-1992, maroon is 1992-1993. While the black top is from 1994-1997

Difference between Kouki and Zenki Sr20DET S13
1) Kouki has Heat Sink Fins on the Head
2) Kouki uses S14 Sr20DET alternators, transmission, pistons, and other "minor" parts.
3) Kouki have the 54C rockers, pistons, and oil squirters, which is found on the S14 and S15 SRs.
4) Kouki have bigger oil pick-up.
5) Kouki have different ECU.
6) Kouki uses 2 different valve cover colors: Black and Red.
7) Kouki has different timing chain tensioners.

I think everyone is trying to figure out the difference between the motors through internet research is mixed up between the RedTop Zenki and BlackTop, or Kouki RedTop. The fact that Nissan is mixing up their SR parts is confusing everyone. There are so many post saying that they are the same besides the production year and color of valve cover. But technically, they ARE different. Even though these difference is "minor," and doesn't really affect the output of the motor, but when someone is planing to build a +400 hp motor, these "minor" differences could mean a difference.

SR20DET S13 Kouki redtop and S13 blacktop is the same.
SR20DET S13 Zenki redtop is different than the Kouki and blacktop SR.

If anyone find this information incorrect, please do correct it.
I just spent several hours in this research, so give me some propz.

Source of Information:
http://forums.nicoclub.com/zerothread?id=59346&page=1
and other websites that i'm having a hard time tracking back.

 

hmmm, I was under the impression that all redtops (91-93) had either a 62 or 63 ECU number. If that's the case, then their "kouki have different ECU" is a generalization -> technically false.

94-96 (s13 blacktop) have an E5 or E6 ECU, which is pin compatible with the 62/63 (redtop) ECU's, but you need the corresponding blacktop O2 sensor.

97-98 (s13 blacktop) have a J4 ECU (and possibly another number corresponding to the auto version). This ECU has to be re-pinned to work with the E5/62 harnesses. It uses the same O2 as the other blacktop.

97-98 motors are identifiable externally over the 94-96 motors by the revised timing chain tensioner on the front passenger (US) side of the head. The revised part has a bump sized like a stack of quarters, where the 94-96's bump looks more like a single nickel. I think that there might be a few revised chain guides as well.

I can't remember if it's all blacktops or just the 97-98 ones that have the revised oil pick up. Either way, the revised pickup is probably one of the most important changes, as it allows the pump to suck up oil even if the pan is severely dented.

Lastly, the AC compressor bracket changes somewhere along the line. I know for a fact that the 97-98 bracket is different than the 91-93 one.

To recap what other's have said. The pistons change in the blacktop to 54C (which is stamped on the piston top, and you can see through the spark plug hole). The bearings in all SR20's are the same except the GTi-R. The piston oil squirters on the blacktops are slightly different than on the redtops, but both have them.

 

Well if the ECU is just slightly different...it's different.
Thanks for the input Epstein.