Went to a dyno day with my B18C Gsr swapped 1999 Civic Sedan and was very disappointed with the numbers.
WHP: 120.8
TRQ: 113.0

I assume the jump at 5,000 rpm was the butterfly valves opening up on the GSR intake manifold?

I just have a short ram intake, stock headers into ebay exhaust with RSX-S muffler, very quiet I love it.
Chipped P28 ecu.
Still revs to 8k rpm, no limp mode, no CEL's
I don't hear Vtec kicking in ~ 4k rpm so that's what I'm thinking the problem is but I need some verification.

Thank you.

Car: 1999 Civic LX

Motor: GSR unknown year, just B18C

Ecu: OBD1 P28

Wire harness: 99-00 SI harness, OBD2 to OBD1 Conversion harness to ecu.

 

Question, why do you have that ECU with the stock intake?
I guess I'm failing to understand why you didn't just use the original ECU at all considering it's a stock GSR.

 

I purchased this car with the swap already in it. The original ECU would have been whatever comes in a 99 Civic LX, would that have worked? I think the ECU and harness were switched to OBD1 because ( I believe ) the engine is a 93 which means OBD1.

 

Wtf does that even mean, you have a gsr engine, not a freakin stock d16y7 so why would you want to say you're running a 99 civic LX ecu. If the ecu isn't chipped than you need to source a obd1 gsr ecu plain and simple.

 

Stop assuming and start confirming these details.

Car:

Motor:

Ecu:

Wire harness:

 

I never said anything about running a 99 civic lx ecu, the first comment on here asked why I didn't just use the original ecu, well that's why because it's a 99 civic lx. Previous owner did the swap, previous owner installed a chipped P28 ecu that's what it's running right now, it's an obd1 harness they used also, don't know the exact details on the harness though. It's a b18c gsr motor, can't say exactly what year it is but I assume a 93 because they switched it to obd1.

The ecu you are suggesting I try, that is the P72 correct?

 

 

See my reply above yours, it has the info you just asked for... really what I'm asking for is this graph indicative of what a dyno looks like with no vtec? And with the info I've given is there anything blazingly obviously what could be causing that.

 

Could be the tune, or it could be the engine. Compression check, leak down test, ignition system , fuel delivery...some things to look into. Check the FAQ section.

 

Your 'info' is your assumption.

So let's fill in that confirmed info. Not your best guess.

Car: 1999 Civic LX

Motor: GSR unknown year, just B18C

Ecu: OBD1 P28

Wire harness: unknown

__________________________________


At the very least, you should be running an obd1 P72. Get rid of that P28. If the car is in fact obd1 converted.

You should look into how the car was converted to obd1...just to make sure your wiring isn't an(other) issue. Buying other people's projects is no fun having to sort out.



Ideally you'd want the 'specs' to all match...not mashed up together. Sort out what you have, figure out your best plan of attack.

 

Looks like you dont have vtec engaging. Im willing to bet that ecu is not running the engine correct or vtec isnt wired in correctly to the ecu and engine harness. Get a Gsr ECU and use that i bet it will run much better as well.



https://honda-tech.com/honda-civic-d...-vtec-2987229/


https://honda-tech.com/honda-civic-d...ivics-2969066/

 

The dyno graph above appears to suggest that the tune is WAY off, not that there is damage to the engine necessarily. The increase or jump in power at 5000 RPM looks like a typical VTEC crossover point, and since there is no circuitry to operate the secondary butterflies in a P28, you will see no change in your graph at the expected RPM. Beyond that, the graph begins to fizzle as the torque dives toward zero. The peak torque numbers are only a few ft/lbs low... you typically see 117-122 ft/lbs from a stock GSR. Since you did not post a graph of the Air/Fuel values with your HP/Torque graph, I cannot be for sure... but the shape of the graph appears to be a modified program on the "chipped P28" that you claim to have. For reference, the stock P72 ECU pops VTEC on at 4600 RPM and the IAB's (secondary runners) activate at 5750 PRM. Remember that the instructions on the chip could be for ANY VTEC engine... not necessarily your GSR. Get it tuned. The three pulls on the graph look like the "tuner" simply advanced the distributor a little after the previous pull.

Otherwise, do as many have said above and get a '94-95 GSR computer (37820-P72-A00 (or A01)). The only problem with changing to the P72 computer is that you will have to do some wiring for the Knock sensor and your secondary butterflies to keep the "Check Engine" light from illuminating and putting the engine in safe mode.

 

Thanks for all of that info.

Supposedly the PO had the engine "tuned" by some guy, I have his contact info so I will call him to see exactly what he used to "tune" it and ask him all the details he knows.

The graph above only has hp/tq because it was just a fun dyno day thing I went to, they weren't the ones tuning it or anything and it was an extra $25 for air/fuel graph, which would have been worth it if I knew it wasn't running right lol.
The group at the dyno day speculated a few things, vtec not engaging, thought that maybe the spike at 5k rpm was the butterflies opening, which after googling the butterflies do open on the manifold at 5k so that does make sense, which would indicate vtec is not engaging.
So could be two scenarios, they set vtec at 5k and tuned way wrong, maybe the timing belt is off a tooth?
Or Vtec is not engaging but yet the butterflies are still opening at 5k.

Updated original post with this info also
Car: 1999 Civic LX

Motor: GSR unknown year, just B18C

Ecu: OBD1 P28

Wire harness: 99-00 SI wire harness with OBD1-OBD2 converter harness

Thanks again. I'll update when I figure out what's going on.

 

Just to clarify... a P28 ECU CANNOT ACTUATE THE BUTTERFLIES !!! This means that the "jump" at 5000 RPM MUST BE VTEC. Also, the P72 ECU opens the secondary butterflies at 5750 RPM... yes, that is nearly 5800 RPM, not 5000 RPM. A tuner could change the activation RPM, but this is uncommon, and LOWERING the activation point is counter-productive on a naturally aspirated engine.

Can you describe what "changed" between the 1st, 2nd and 3rd dyno runs that are printed on the sheet you have posted above ???

 

Im thinking the tuner added fuel on the next 2 runs, op states it was just a dyno run for base pulls.

 

Op if I were you I'd just get an obd2 p72. Fix whatever codes might pop up, call it a day.

 

Your VTEC on a B18C1 should kick in at 4400RPM, not 5K+.
Your ECU is the wrong ECU for the engine, a P28 does not have (IAB) butterfly controls, unless they were soldered on to the board. This will cause the engine to fall flat on it's face at 6K.
Looks like the "tuner" left the VTEC at the stock D16Y position (5K) either way.

Your options:
1. Get the correct ECU (P72) and call it a day.
2. Add IAB to P28, correct the VTEC crossover, retune with base GSR maps.
3. Replace GSR intake with LS intake, and get used to the LS numbers.

...one more thing to note: I believe all 2000-01 P72 ECU's require a chipped key and the key reader in the ignition.

 

Did anyone think to ask the compression numbers for all we know there's 120 across the board, while there are other things wrong (we can all agree) that's an absolutely sad dyno sheet. Also being that stupid gsr head flange his only option is an aftermarket intake or the stock p72 ECU to address the IAB concern, I would get the correct ECU. Kind of sad how many of the issues here(H-T) are related to hacked up swap jobs OP just got unlucky...

 

So much confusion and varying info. Poor OP.

P72 ECU's are stock for the GSR. With a P72 ECU, you can expect:

-4400RPM VTEC (you won't hear it or feel it. If you have an exhaust, you *might* hear something).

-5800RPM butterflies. You'll hear and feel this.

Your car has a chipped ECU. Does the intake manifold still have the butterflies? Or are they propped open? The current ECU won't open your butterflies (unless it is a P72 with the IAB function left intact). If they are not propped open or deleted....that may be your low HP issue.

Your car should be making like 150-160HP depending on your bolt ons.

 

Thanks for the thoughts.
Plan:
1. I will do a compression test in the next few days and let you know the results.
2. Will most likely prop open the IAB's for now, then over the winter most likely take them out of the intake altogether.
3. Since they're fairly cheap I was going to get a GSR basemap chip and see if that helped.
4. If that doesn't work I already have a USDM P72 ECU, if the GSR basemap chip doesn't work I'll buy a OBD2A to OBD2B conversion harness and install the P72.
Got in contact with the person that put the tune on the car, said it was just a basemap and that was put on the car, and that it has the "smaller OBD2 injectors" so with a new map it will need checked with a wideband.
Smaller OBD2 injectors? Any ideas what that means?

Looking at the dyno sheet again, didn't notice this but the very first pull was the 120 hp one, the next two pulls actually went lower each time, strange.

And sorry for the confusion, but I think most of it was the first responders assuming a lot of info instead of simply asking.

****EDIT: I asked him to clarify, and for whatever reason they reused the D16 injectors instead of B18, so for flow instead of max 230 it's maxed at 180. I'm curious if this is the whole problem right there.****

 

The y8 injectors are 240cc just like all the b series ones, so what you're saying is he used y7 or another 190CC injector. Considering how dumb the kid seems going by what you said I hope you paid dirt for this "car", another reason i'll never touch these old *** cars morons hack them to ****.

50cc is dubious to result in that much of a loss as stated you should be in the 150-160 range give or take, do a compression test that will be the last hint for all you know you've got 170 psi in all 4.

 

Feel good about the compression test, just did it and it was 210 - 210 - 205 - 205, slightly cold so maybe that's why it's slightly low numbers.

 

You had the p72 the entire time and didn't bother to plug it in to see if there was a difference? I would've been bought the jumper harness and swapped ecu's by now.

Did you do any maintenance on it at all.

 

Lol no actually I just picked that up this weekend, hesitant to spend another $80 just for the conversion harness if the ecu is not even the problem, going to see if proper injectors make it better.

 

You are going to want to run the correct ecu AND injectors, not one or the other. $80 is a small price to pay for doing something the correct way.