CTSC underwhelming...?

Arshad said:
More disappointing news. I did the dyno and it's only measuring 289rwhp. I noticed on the way home that the AC was on, which probably subtracted 10hp (?), but it's still off.?

I am a little confused. You said that after the tune it was no longer underwheliming and you noticed a big difference in performance. Now you are saying it is DYNOing at the same HP level as originally. :confused:
 
Aftermarket Fuel Pump

The Walbro is a drop-in replacement for the OEM pump.

It has been a while since I looked into their permutations but they have HV, HP and HP-HV.

I purchased the HP-HV for something like $250......delivery was within two weeks.
 

I am a little confused. You said that after the tune it was no longer underwheliming and you noticed a big difference in performance. Now you are saying it is DYNOing at the same HP level as originally.


Well here's the deal. After they fixed the ESM issue, I could then hear the supercharger even in 2nd and there was DEFINITELY way more power. Not underwhelming at all! However, based on my previous dyno, I was still worried about my lean A/F issue so for the past week and a half I've been driving like a grandmother and not putting it under any boost until I could get a proper A/F reading (pre-cat).

Yesterday, for the first time since that previous dyno I hammered it in 2nd up to about 6000 RPM's and it felt "weaker", but I thought it was just my imagination and the fact that I hadn't been pushing the car for the past several days. I mentioned this to the dealer as well, but figured that today's dyno should conclusively tell me what the real deal was.

So what I'm seeing is a bit higher HP (keep in mind that I had left the AC on accidentally), but still well under where it should be. I don't know if it's gotten progressively weaker since that day they first adjusted the ESM .. it definitely felt like it to me, even before knowing the new dyno results.

Maybe it's the fuel pump that's starting to fail and that's what's causing it? I don't know.

Andy: Is the regular 255 HP ok for a low boost CTSC application, or is it necessary to get the HP HV with comptech's FPR?
 
Walbro Fuel Pump

You should be able to find it for ~$125 delivered.

Actually, I think it was closer to this number vs the $250 that I mentioned.....don’t have my paperwork with me.....going off of memory.

Andy: Is the regular 255 HP ok for a low boost CTSC application, or is it necessary to get the HP HV with Comptech's FPR?

Discussions with other NSXers would lead one to believe that the HP version should be adequate; however, I would like to state that I am not an “expert” in this area. I simply chose the HP-HV version, knowing that I would be removing the factory fuel pump resistor and tuning with the Split Second box.
 
Donwon: Hmm, now I'm really confused. I was certain it was the fuel pump that was the issue when I left the dyno but based on what you and sjs suggested, as well as what Shad at comptech mentioned it seems like maybe that's not the problem.

The dealer called up Shad who said the following:

1) 12.3-12.5 A/F is in the acceptable range, and nothing to be worried about. I'm a little concerned because I do plan on running it in cold weather which will lean it out further.

2) Fuel pressure dropping off after 6k rpm is normal. Max boost kicks in around there, and then tapers off to about 5psi at redline. A small drop in fuel pressure is normal and expected. A large drop eg. 30-40psi or more is a problem. I don't know how much it dropped off because the dyno guy immediately shut it down when he noted the fuel pressure falling rapidly. We'll have to test for this, as well as measure boost again. When it was tested last time, I'm fairly certain it never went above 5psi (this was pre-ESM voltage adjustment).

3) He's only seen a couple of cases where the OEM fuel pump needed to be replaced, and this was usually on high mileage cars (one example was a 170k mile car). My car has just under 50k miles on it (1991). He doesn't think the fuel pump is the problem.

I had concluded that not seeing a measurable difference after adjusting the regulator indicated a problem with fuel delivery. Donwon's similar experience using an upgraded pump seems to suggest that this is not always true.

The fact that AF remained in the 12.3-12.5 range during the run seems to indicate that shad is correct and that the correct amount of fuel is being delivered. If it dropped off unacceptably, I would expect AF to lean out big time after 6k RPM, which it didn't. I still don't understand why it's running slightly lean if fuel delivery is not an issue given that the kit is supposed to run conservatively rich.

In any case, the car is going back to the dealer for further testing, and I think I'm going to go ahead and replace the fuel pump anyways, even if it's not the root cause. It'll help me sleep better knowing that I've got a pump that can easily handle the load. SJS, I will recommend that they do a boost vs fuel pressure plot per your suggestion.
 
Man... Just to much troubles for me...this must be driving you nuts.

Did Johnny get this much problems when he had his CTSC installed ?

I feel for you man, I'm sure they will figure it out.

Bram
 
Yeah after reading about how it was the most straightforward and conservative kit, I really was expecting more of a "plug and play" experience. Especially after spending all that money, it's frustrating to still not have it 100%, but the good thing is that Acura Woodbine is behind me all the way and are committed to making sure that I'm satisfied. Paul in their parts department is simply an incredible guy who really has the customers interest at heart, which is making this experience bearable. Comptech is also 100% behind their product, and everybody says that Shad can troubleshoot anything so I have confidence that this will all be worked out in the end. I just hope that my car is in good enough condition that I can drive down to NSXPO without worrying about it.

I know Johnny ran into some issues as well, but I think they were different problems, and I think he's up and running properly now.
 
Well all things considered, at least the car is drivable and thats not bad. It seems just a matter of getting it to its potential. Im in the same boat. Your A/f is actually decent from what you got to measure of it. Mine was dipping into the 9's. I havent had much luck with FI, so im looking forward to seeing how this get worked our for you.
 
Your pump is probably fine and I wouldn't bother to replace it unless you really don't care about the extra expense (labor is far more than the part). That's why I mentioned that the pressure does fall off at high RPM along with boost and didn't necessarily suggest a problem, but if you wanted to be certain you could plot boost vs fuel pressure. I suspect Shad is correct and everything is fine in that area, but the test would put your mind at ease regarding both the pump and regulator. As you mentioned, the AFR is a bit leaner than I've come to expect from the CTSC but they are sometimes a bit rich in the middle then leaner towards the top. If Shad is comfortable with it then I wouldn't be too concerned, assuming that you can trust the wideband in question. Did you monitor it at idle to confirm that it is correct (~14.7) at idle and low loads?

But that still leaves the question of where the power went. Since AFR is reasonable now I guess the ESM isn't freaking out again, but a quick check couldn't hurt. If it is building boost and the AFR is correct the that doesn't leave much. The basics are compression (aided by boost in this case), air & fuel in the correct ratio, spark (no reason to suspect that, but worth thinking about), timing (not generally a problem with the stock ECU), and valves opening and closing.

I wonder if VTEC is engaging? Your power numbers might make sense if you never got off the low RPM lobes. (Edit: on second thought, the power curve would probably be quite different) Or perhaps the VVIS is not opening. The latter can be checked visually and you can even open them manually. Hmmm... the ESM is worth another look. What if it is putting out enough to get out of closed loop, but not enough to trigger VTEC? (unless there is an RPM and throttle level at which it switches regardless of load, I don't really know) I suppose that if it went to open loop maps but stayed on the lower lobes it would probably be rich, so maybe not. But either way, you might want to confirm that both VTEC and VVIS are working. There just aren't that many things that can be wrong.

True story from last week: First time out with my new engine for the 510 it felt a bit rough and not significantly faster than the previous one especially at high RPM, despite a significantly more aggressive build. I did a quick check of timing and a couple plugs but didn't see a problem, so I started to suspect cam timing. But it was late and I was running it in the trailer with minimal light, and suddenly saw a strange flashing blue ring of light. Aha! I pulled #3 spark plug and found that the porcelain was cracked all the way around, right at the base where it goes into main metal portion. The spark was grounding out. It still got enough to run on all four at idle and modest loads, but not at higher ones. I replaced the plug and suddenly had the engine I expected. Funny that it wasn't even rougher, but I guess that cylinder fired sometimes better than others. Now the car can be steered with the throttle at will, which is a blast after doing a spec Miata race where momentum is everything.

Anyway, get your tech and Shad to start at the top of the limited list of possibilities again and knock them off one at a time.
 
Don, yes that's true. The problem is this past week I had been driving it like a grandmother and not putting it into boost thinking my AF might be too lean. Now I find the AF is decent, but now I'm worried about fuel delivery above 6k RPM's. I dunno, I'm going to continue taking it easy on the car at least until the fuel pump is replaced. If the car is making ~ 300rwhp and needs some tuning to get it to 320 or whatever, I'm fine with that. I just don't want to have to drive around gingerly, short shifting all over the place because I'm afraid my engine is going to blow up. I especially don't want this to impact my enjoyment of taking the car to NSXPO. Ah well, what can you do right? Gotta suck it up and make the best of it, and hope things get resolved quickly.
 
SJS,

Although initially I was convinced the fuel pump was the problem, the more I read and think about this, the more I suspect the pump might actually be fine. The only thing that keeps nagging in my brain is the fact that it's running leaner than the typical CTSC install. The dyno guy noted the same thing compared to the other CTSC NSX's he's seen. Unfortunately I didn't check to make sure it was running 14.7 at idle, but I trust these readings over the older ones since he tapped in pre-cat with a wideband.

It seems to me that upgrading to the walbro may not necessarily help, but it also won't hurt and I have a little bit of extra piece of mind. You're right about the labour -- the dealership estimated 4 hours.

Sparkplugs were changed about 12000 miles ago, so I think they should be good.

Boost they're going to check again. Fuel pressure they will recheck again. The dealer mentioned something interesting.. he said it's possible for the timing to have gotten retarded when I had my timing belt replaced if the cam jumped a tooth (?). So they're going to check the timing just in case.

Tomorrow I'll see if I can hear it kick into VTEC, and also suggest that they look into that to make sure both VTEC and VVIS are kicking in.

Thanks for the suggestions!
 
(somebody) Correct me if I'm wrong, but I think after every major tweek of fuel pressure, etc., that since your running off the stock ECU it would be a good idea to reset it by pulling the clock fuse for ~10 seconds. I put 20000 miles on my car with a crappy turbo and stock ecu with RRFPR and every time i reset the ECU it ran great for like half an hour until it 'learned' that it was doing something fun then it got conservative on me and tried to make it back into a regular motor again. Thats the jackass version of a description, but it basically is the truth in non-scientific terms, at least by my experience.
 
I also have the CTSC and I can tell you that when it is right it is a huge difference. I have had issues with the High boost version but that is a different matter.

I can't help you with the technical stuff, but I did notice that you thought you would see a 10hp increase by turning off the A/C. This isn't the case as the computer automatically disables the compressor under WOT so the hp numbers you are seeing won't be improved by turning it off.

Good Luck, I hope everything gets worked out.
 
Arshad,

I feel your pain. I had similar issues a while back, and am now VERY familiar with the CTSC and its workings. Give me a call 760-931-9100, I call tell you what I know; it may or may not help.

Gene
 
I did reset the ECU after the ESM voltage adjustment, but since then I've been running the car fairly gently. How long does it take to learn? Maybe I'll try resetting the ECU again and drive it normally and see if it goes back to how it was.

I drove it semi-hard this morning and it is definitely not as snappy as it was when I got it back post-ESM adjustment. Could that thing somehow have slipped back to the old setting or something?? The dealer doesn't think that's the case, but it's something that will have to be checked.

Carguy: Thanks for that info on the AC, I had no idea -- that's a very important thing to know as we try and sort this out.

Gene: I appreciate the offer, and I'll definitely give you a call.

I just wanted to say to everyone.. THANKS! This is a really trying time for me, and it's great to have the support of this incredible knowledge base. I've learned a lot in the past little while, and I owe it to you guys. This is what makes NSXPrime so awesome -- the incredibly tight-knit group that's always willing to help. Thanks!!!
 
A friend of mine and former NSX prime member (nrs) had a similar problem. He had a '96 NSX that dynoed at 299 hp at the wheels with stock headers and exhaust. He bought Comptech headers and exhaust and dynoed again (less than a week later) and got 299 hp. After much searching, it turned out to be a bad fuel pressure regulator. That was switched and he came up to 324 hp at the wheels. I don't know if it will help but you may want to talk to Mark Basch, he's done more of these than just about anyone else.
 
SCS2k: Yeah one of the things that was considered was the FPR, but monitoring the fuel pressure seems to indicate that it is doing its job properly.

I'm taking my car in tomorrow and they will recheck all the connections and look at the ESM voltage again. Mine is currently set to 2.918, and they may bump it up a bit to 2.92 to see if that makes a difference.

I think I'm going to go ahead with the Walbro install as well. In researching this, I noted that higher output pumps can sometimes flood the fuel return on the stock regulator. Is a Walbro 255 HP going to be an issue with the Comptech RRFPR? I know people said it was a drop in replacement for the OEM, but does anything else have to be changed for the fuel return?

I'm going to let the dealership continue talking to Shad to try and figure this out. If they come up with nothing, then I'll contact Mark Basch and see if he has any suggestions.
 
Carguy! said:
I also have the CTSC and I can tell you that when it is right it is a huge difference. I have had issues with the High boost version but that is a different matter.

I can't help you with the technical stuff, but I did notice that you thought you would see a 10hp increase by turning off the A/C. This isn't the case as the computer automatically disables the compressor under WOT so the hp numbers you are seeing won't be improved by turning it off.

Good Luck, I hope everything gets worked out.


Seriously? ABout the AC shutting off under WOT. I didn't know that... shoot.. just yesterday i was being young and irresponsible, racing a turbo mustang, and he got the jump cause i was trying to shut off my AC. I only race in school zones of course, between the hours of 2-4 pm when running over kids is most likely.
 
The AC is not diabled under WOT acceleration; when I dynoed my car, IIRC, I had 245 rwhp, 235 rwhp with the AC compressor on full recirculate. Both runs back to back. At least, my NSX didn't disable the compressor.
 
The latest in the saga...

I took it in this morning and the first thing they wanted to check was the timing. They had 3 different techs look at it to confirm that the timing was off by "half a tooth", which they attributed to improper timing belt installation. On my work order it says "Found that front head exhaust cam is off by a tooth" and "After thoroughly checking for concern he has determined that the timing has been retarded by previous dealer when changing timing belt".

Is being off by 1 tooth equivalent to being retarded by 1 degree (and what does it mean to be off by "half a tooth"?) If this is true, could it explain the 25-35hp that I seem to be off? I thought it would be more along the lines of 5hp difference. Anyways, the dealership does not want to diagnose this further until the timing belt issue has been corrected since they feel that this may be the root cause.

Now here's the problem... If I recall correctly I had the timing belt + water pump replaced last spring, and the warranty only covers 1 year. Do you think I have a case to go back and have them fix it at their expense given that they installed it incorrectly to begin with? Also, how long does it typically take to replace the timing belt only? I was told it was a 14 hour job -- that seems very high to me. I thought it was closer to 7-8 hours. I'm dreading the thought of dumping another $1k to get the timing fixed. :(

And now NSXPO is coming up next week and I'm afraid I'm going to be stuck in a situation where my car may not be in shape to be driven down. Question: Is having the timing off by 1 tooth a problem or can I drive the car normally? It sounds to me like it's an extra bit of protection from detonation if anything -- is that right?

This whole ordeal has just been so incredibly frustrating...
 
i'd definitely call the place that put in the belt originally. WHat have you to lose? Besides, you paid probably >$1000 for the timing belt etc so i'd hope for some reasonable expertise. they'll either say bring it back, have the other place fixit and we'll pay, or screw off...
 
I talked to the service manager at the original dealership and he was very accomodating and asked me to bring it in on Monday so they can have their "NSX Expert" look at it. He didn't want to talk money until he had a chance to look at it. I'm hoping they goodwill it since they installed it incorrectly to begin with.

Does anyone know whether that 1 tooth off on the exhaust cam can result in the ~30hp that I seem to be off?
 
I don't have a definitive answer for you, but will offer a few comments. As you seem to be starting to understand, cam timing is not the same as ignition timing. When the ignition is triggered from a sensor on a cam (as opposed to the crank or a separate shaft entirely) they can be related, but still not the same thing. In this case there are 4 cams and it sounds like you were told an exhaust cam is the one in question, but it could be off in either direction with different consequences. If your pre-CTSC dyno looked "normal" then it might be tough to convince the shop that the problem happened a year ago. They may claim it jumped a tooth but probably won't have a good explanation of how or why on a relatively fresh belt. Hopefully if they confirm it is off a tooth they will fix it and all will be well.
 
As you seem to be starting to understand, cam timing is not the same as ignition timing.

Yeah, I was initially confusing the two .. duh. As you can tell, I really don't know the first thing about engines, but this experience has been useful because I'm starting to understand how it all goes together now.

About the belt jumping a tooth: I wonder if this indeed happened? Like I said, when I first got the car post-ESM mod, it felt stronger than it is right now. I wonder if it was fine at that point and jumped a tooth afterwards? Anyways, I should know better after they look at it on Monday.

BTW, the shop that installed my belt originally doesn't know about the pre-dyno. In any case, I felt that at 251hp I was in the range, but a bit on the low side for a 3.0l with headers/exhaust.
 
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