ls ecu on SI - Honda Prelude Forum

OSOFAST10 · 02-04-2003, 04:52 PM

i heard you can put an integra ls ecu on a prelude si and it will run faster. well a few questions
1. is this true?
2. how hard would it be to swap my ecu?
3. how much faster will this make my car?
4. is this even worth gettin?
thanks for all your help people.

95BlueSi · 02-04-2003, 05:15 PM

I have never heard of such a thing...

But then again Im just learning about all this stuff. Have you tried searching for it? On this board I mean.

OSOFAST10 · 02-04-2003, 05:25 PM

i am new to this site and i really don't know how to search to well. i did it once and a lot of crap came up. so i was just trying to make it easy and see if someone out there has done it

Si4WS · 02-04-2003, 06:29 PM

I don't think this is possible unless (maybe) the ecu is re-programed . . .

19924ws · 02-04-2003, 08:17 PM

It is perfectly possible it is a direct swap. The LS ECU has better fuel and ignition maps. It will make more power. These are the words of Javier owner of JG. If all y'all doubters would like to call him and ask here's JG's # 1-626-281-5326.

brendon2k · 02-05-2003, 09:47 AM

Quote:

Originally posted by 19924ws
It is perfectly possible it is a direct swap. The LS ECU has better fuel and ignition maps. It will make more power. These are the words of Javier owner of JG. If all y'all doubters would like to call him and ask here's JG's # 1-626-281-5326.

why would it have "better" fuel and ignition maps? it is made for a non vtec b18 not a h23.

Absolut · 02-05-2003, 11:15 AM

Doesnt seem like it would give enough fuel for the extra 500cc's

SikRedRX-8 · 02-05-2003, 11:28 AM

Look the with the LS ecu you would most likely lean out because the H23 uses more fuel, than the LS so when you get higher into the RPM it would start to lean. And that is just to name one problem. And if you don't believe me call me, I have done everything under the sun 1-505-332-2***.

19924ws · 02-05-2003, 11:40 AM

The same reason people use the GSR ECU's for v-tecs. They (integra's) have a higher hp/L. The ignition and fuel maps are more agressive. They would give plenty of fuel, fuel delivery is based of the A/F ratio number that the O2 sensor sends, not displacement. It is just a better tuned ECU, I don't know why it is...it just is. Why is the H23 a seemingly better engine than the b18? The b18 puts out 8.21 MORE hp per liter than the H23. 140/1.8=77.78 160/2.3=69.57. That is to say if the b18 were 2.3L it would have 178.89hp. The only way to see is to swap 'em out.

SikRedRX-8 · 02-05-2003, 11:58 AM

You have to be kidding right? Well let me break a few things down for you. first when you run the Gsr ECU on a H22 it will lean really bad, so you have to either get Hondata or a V-AFC. As far as Hp per litter, come on that agument is so played out. I am not flaming you at all just explaining it to you. Go put a B18a in your lude and race a H23 and that will tell you why, the power band in the H23 is so much smoother and from what I have seen in friends dyno's the LS when compared to the H23 makes less to the wheels, not compaired with each other but to them selfs. In my opinion the H23 is better in everyway. If you decide to use a LS ECU go right ahead but I explained to you why not to. In case you don't know, to lean out is VERY bad.

red92si · 02-05-2003, 12:03 PM

What about the ignition map on the LS ecu? Is it better than the Si ecu?

19924ws · 02-05-2003, 03:05 PM

I'm not sayin if you put the LS motor in you'll be faster than an H23 just that is has more hp/L nothing more. How bout upping the fuel press would that take care of the lean situation? Send me a PM of what ya did to your ride, and what ya run in the 1/4.

[SUB[EX] · 02-05-2003, 06:56 PM

hmmm, im pretty sure when you swap in the LS ecu it has to be reprogrammed.

Si4WS · 02-05-2003, 07:38 PM

Quote:

Originally posted by [SUB[EX]
hmmm, im pretty sure when you swap in the LS ecu it has to be reprogrammed.

Thats what I was saying.

red92si · 02-05-2003, 07:54 PM

Quote:

Originally posted by [SUB[EX]
hmmm, im pretty sure when you swap in the LS ecu it has to be reprogrammed.

though you could swap in an LS ecu and use an SAFC to reconfigure the fuel. I just want to know about the LS ecu's ignition timing vs. the H23 ecu.

19924ws · 02-05-2003, 08:57 PM

No JG told me that putting the LS ECU in was an alterative to having the H23 one remapped, so why would I get an LS ECU remapped? If that were the case then stay with the H23. Also he said all I'd need was a FPR to tune the fuel. Next time I talk to him I'll get into more depth. Mike

red92si · 02-05-2003, 09:41 PM

FPR would be a good addition, but it would be better to fine tune the ecu with the SAFC.

19924ws · 02-05-2003, 09:47 PM

a guy over on h-p.com is saying that the ecu would slowly remap itself anyway? Is that true?

19924ws · 02-06-2003, 10:52 AM

OK I checked and here's the 'skinny'. The ignition map is more agressive which is good for N/A. The fuel map is better, but eventually will change to what it thinks is a perfect a/f ratio, which is slightly leaner than what the H23 thinks is a perfect ratio. Everyone knows that ludes run hella rich when untuned....which is good for safety but not perf. Since it would only be in an N/A car the leaner mix would be fine, because its not too lean. Also the better "perfect ratio is only good for part throttle and full throttle below 4000rpm. Once above 4k and are at WOT both of the computers will go to "open loop" which is spraying as much fuel as the injector will spray. All in all the LS ECU is only good for the part throttle, full throttle below 4k, and the ignition agressiveness. If you can find one cheap enough...around 100-150 then go for it but if not it would be a waste. Mike

red92si · 02-06-2003, 11:21 AM

Just found out that www.inlinefour.com, will retune LS ecu's... but they don't list retuning service for any Prelude ecu's.