Rev limit for Fast and Fugly CRX - Tuner-Junction

apexinghonda · #1 (**permalink**) November 6th, 2006, 05:01 PM

The beast is back to life. It has sat for a few months to try and fix the mystery temp spike issue previously posted on here. I have been soooo damn busy I have not been able to touch the car. Never really found a definitive answer BUT now I have a set of Longacre mechanical gauges sitting up on my dash and a big dual range Autometer Monster Tech. Before I have been using the stock tach which stops at 8K revs. LOL. I would just run it past 8k, let it peg and shift based on sound. Supposedly the car has a soft rev limiter at 9.3K revs but I have never hit it. My question is what is a good place to shift?

I had a dyno sheet on the car from when I first bought it and it made peak power at 8.8K revs. I think hp was 195 and tq was 138ft.lbs. The car has Hondata. I am thinking about setting my shift light for 9K. While I am sure I could wring it out more I don't want to shorten the engine lift too much.

I ran the car last night and the new mechanical gauge read 170 degrees on a chilly evening. I have a full fluidyne radiator and a meziere pump so I have a lot of cooling capacity. I took it out to my "test road" (long stretch of road with no sideroads) to wring it out on an "installation lap". I got to maybe 185 degrees under the heavy throttle. The main things is it did not do the temp spike thing.

I almost wonder if it was my electrical gauge. Did the head gasket, new thermostat (drilled), new hoses, bunged in a sensor fitting into the water heater outlet from the head (I have no heat or A/C. Heat exchanger can burn your feet in a wreck anyhow).

So now that I have a "real tach" what do you think (Jadkar?) Am going to Road Atlanta this weekend to work corners during the SCCA big Improved Touring race (American Road Race of Champions) and they have a PDX during quiet time for the corner workers/volunteers for 2.5 hours on Sunday. I have not gone there all year and I am Jonses for it.

After that and PBOC at Barber in two weeks I am going to put the car on a dyno and find out just what numbers I am getting.

Thanks,..

njn63 · #2 (**permalink**) November 6th, 2006, 05:13 PM

you wouldn't happen to have the dyno sheet would you?

If not i'm sure jadkar or one of the other guys with experience with B18's will know a lot more than i will.

apexinghonda · #3 (**permalink**) November 6th, 2006, 05:23 PM

I doubt I can find it. But I plan on getting it on the dyno and find out what my numbers are these days good or bad. Hell it felt strong last night. When I get it dynoed I will post it. With my close ratio tranny and 4.785 it is pretty easy to stay on top of the power band. vtec kicks in at 6k but my spread is a lot narrower than that.

Barry

triniskill · #4 (**permalink**) November 6th, 2006, 06:50 PM

For a rev limit that will be perfect will take some time to get..
the best advice I can give you is..to look at your dyno sheet and see were you pwerband really starts to climb and from were it drops..then take the car out and shift at different rpms..
which I mean lets say your power band really starts to climb at 6k(when vtec kicks)..power stops to climb at 8500. So now take the car out shift a 9000-9500rpm..find the right shift point so when it drops down..it starts to build up at 6k..so when you shift your are still in the power band the next gear..
Hope I didnt confused you anywhere..and you get what I mean..

apexinghonda · #5 (**permalink**) November 6th, 2006, 10:11 PM

Yeah, I know what you mean. Having a USDM type r trannie with a jdm 4.785 final drive it pulls pretty strong and there is not a big drop in rpms with that set up. I remember the dyno sheet having the car making max power at 8800 rpms. What I meant to say which I obviously did a poor job at it is what is a reasonble redline limit for my set up as in the max rpms in not really stressing the crap out of the motor. It is still pulling strong as hell at 9K but I don't think I really want to go farther than that on track regularly in that I fear of shortening engine life exponentially. Maybe I am wrong on that. Does that make sense. It is from a engine life management stanpoint. Thanks.

Barry H.

jadkar · #6 (**permalink**) November 6th, 2006, 10:17 PM

If you're asking me about the red-line, I don't know. I mean 200 RPM is not much more gain to risk the outcome of a busted valve (trust me I know). Then again this is just your track rat so it might be worth it to you.

As far as your cooling spike, it sounds like you are chasing ghosts. The car has been running fine anyway, right? Maybe it was just your gauge, or maybe it's just the fact that CRXs are usually not being thrown as hard into the corners as you are and the cooling system is just not designed for it. Regardless it doesn't seem like it has caused you any damage thus far.

88 rex · #7 (**permalink**) November 7th, 2006, 07:34 AM

I'd say 9k would be a reasonable redline. You have the valvetrain (Toda right?) to support well beyond that, and your cams seem to be making power way up top.

Ideally, I think you would want to shift a little higher, BUT you want to sacrifice a motor for track days. If you were racing then it would be a different scenario.

Wind that thing out Barry and hope for some piston contact that way you can throw in a K and be competitive in Honda Challenge

apexinghonda · #8 (**permalink**) November 7th, 2006, 10:32 AM

Quote:

Originally Posted by jadkar

If you're asking me about the red-line, I don't know. I mean 200 RPM is not much more gain to risk the outcome of a busted valve (trust me I know). Then again this is just your track rat so it might be worth it to you.

As far as your cooling spike, it sounds like you are chasing ghosts. The car has been running fine anyway, right? Maybe it was just your gauge, or maybe it's just the fact that CRXs are usually not being thrown as hard into the corners as you are and the cooling system is just not designed for it. Regardless it doesn't seem like it has caused you any damage thus far.

The motor seems fine and doesn't sound strain at 9K so I am going to just keep it there. I have a Toda spec B cam and Toda springs. Sometimes I short shift it anyhow. I will find out thise weekend if my cooling issue is gone. Road Atlanta is fast and high g so if it passes that test I am good to go. The CRX's cooling system can handle the Gs. There are way too many many CRXs racing in the improved touring class in the southeas SCCA division that have no issues and are competitively fast (as in podium finishers). If it is a ghost or not (I will take a faulty gauge anyday) I was very paranoid about the temp issue and watched the gauge like a hawk (and would do a cool down lap immediately) which takes away from the fun of driving. It will be nice to be able to run a whole session.

Thanks.

88 rex · #9 (**permalink**) November 7th, 2006, 06:33 PM

Barry, do you have oil pan baffles?

apexinghonda · #10 (**permalink**) November 8th, 2006, 05:28 AM

Yes and no. I bought a heel toe mugen replica baffle plate which has not been welded in yet. It will be in December. I have not had any oil starvation issues or oil pressure issues that I can tell. I run 15w-50 in the motor anyhow because of the duty it sees. Have had the car two years now and 95% of it use is on track. Once I get through with the PBOC event at Barber in two weeks, the oil pan comes off to tack weld in the baffle and put in a bung for the oil temp sensor for the mechanical gauge. We are working out the plumbing for setting up a mechanical oil pressure gauge as well. A braided line and T that mounts up at the firewall. No anyone that has that set up to buy "predone"?

Barry H.