Does anyone else have this setup? We put some of these in my friend's 2000 ITR. He also currently has the following:

-Mugen 4-1 header
-Mugen exhaust
-Mugen valve springs
-Mugen head gasket
-B&M FPR set at 52psi with the vaccum hose off
-AEM Intake

We also installed AEM cam gears at the same time. His car is running like total junk. It feels very weak in the bottom end and it seems to lag badly once it hits VTEC (from about 5700 to 6200). Once it's over 6200 it seems to pull pretty nicely.

His previous best ET was 14.6@96mph. The best we could pull out of it today was 15.3@89mph. What gives?

I told him we need to tune the cam gears and the fuel on the dyno, get a new chip with custom VTEC crossover points and 9000rpm fuel cut, and play with his fuel pressure setting a bit.

Am I on the right track here? Does anyone else have any experience with these cams on an ITR? Any suggestions would be welcome.

 

he has all of that mugen stuff and buys crower cams
well i have no experience with those cams, but i have been told they are similar in specs to toda spec c's. correct me if i am wrong. anyway with those you should kick vtec in at 6800-7200 rpms (spec c's). also take it to a dyno and tune them. then you will see what they like. i also noticed that your fuel pressure is very high. you should get some larger injectors. when the fuel pressure is too high the injectors do not run efficiently and heat up the gas. that is all for now. let me find some specs on the cams and i will let you know.

 

OK here is the deal, I have these cams, look at my sig for the setup. Vtec should not be below 6k on these. I advanced my intake cam 2 1/2 degrees and the exhaust cam 2 degrees. I am running a mugen n1 ecu. The car clearly runs rich but when I leaned the fuel out with the vtec controller I lost power. I have a stock bottom end, my compression is maybe 10.2:1. I dynoed at 176hp and 121tq this is with a stock JDM cat on there, 28" resonator and a muffler. With the exhaust on I have run 13.7's, with it off I have run 13.3. So the cams can make power, but they need to be tuned. Let me know if you have more ?'s

BTW my fuel pressure is the same and I rev to 9k, I peaked horsepower at 8900


[Modified by slivic, 9:09 AM 8/1/2001]

 

when you go to a bigger overlap cam, the dynamic compression ratio decreases as the cylinder pressure is bled out at overlap.
Since your friend has upped the static compression ratio, with a mugen gasket, this should not be as big a problem as you go to the Crowers. BTW buying Mugen ensures one thing: you pay more.

The VTEC switchover needs to be set higher at around 6300 rpm for the Crower 403's so that you aren't bogging down in the 5700-6300 rpm range from being too rich air:fuel ratio-wise with that bigger VTEC lobe. You will need to tweak the fuel map to get that nice flat torque curve like the one Jack had on his Toda cammed ITR. (Get a Field VTEC/fuel controller)

I agree that cam gear tuning on a chassis dyno with a Dynojet air fuel meter should clean up things. Longer valve timing may help get more air fuel mix into the combustion chamber in these lower rod ratio engines which have less piston dwell time at TDC and faster piston speeds away from TDC shortening the fill time. You just need to find the sweet spot in the longer overlap (move the lobe centers closer to each other for more overlap) to make more peak power .

Just a quick question for my own curiosity: what's the valve lash used and the lobe center with 63403's?

cheers

PS Just for accuracy sake FYI: Crower 403's are not close to C's BTW. Here are the specs on their respective VTEC lobes (and we know the Toda's nonVTEC lobes have more duration than the ITR stock VTEC lobe!!!):

Toda C's

INTAKE : lift - 12.5 mm, duration - 255 @1mm
EXHAUST: lift - 12.5mm, duration - 255 @1mm

Crower 63403's

63403

INTAKE: lift - 11.98 mm,duration - 246 @1mm
EXHAUST: lift - 11.83 mm, duration - 238 @1mm

Yes I know: these are not the advertised durations @ 0.0143 in. lift that you see on the respective Crower and Toda websites. And we all know that to compare cam profile durations, you must use the standard comparison at 1mm valve lift.
BTW I like the Crower cams (value performance at a good price) and Brian Crower is a class act. Please don't tell me about their valvesprings and Ti retainers and the "stories" about them. The old Ti retainers that needed to be milled for proper installed height are no longer sold and the stories of valve float with Toda cams using Crower springs: no-one told me whether these occurred with the 68185 springs or the proper 68186 Eibach ("German") dual valve springs (190 lb/in). Trying to pre-empt any negative posts about Crower...yes I know Steven had a bad experience with Crower valvesprings/retainers on a customer b16a and posted the pic...




[Modified by Michael Delaney, 9:01 AM 8/1/2001]

 

I agree, you need a fuel controller..........

 

Thanks for the info guys.