Problem: Dyno tuned today, and whenever the car hit vtec, power would drop down dramatically. Had it from 5500 rpm all the way to 7000 rpm, no matter what, it'll lose power.

We checked:

vtec solenoid, dizzy (coil/ignitor), oil level, TPS sensor.

Originally, the TPS sensor was a bit outta wack, throwing a code. However, the car ran better with the code thrown. Once we cleared the code though, the car still sputtered/misfired at vtec. We got a couple of clean runs in, but once we touched the vtec point, the sputtering occurred again. The only thing we think it is now is the cams. I bought some "Blox Type B's" from an HTer. We played with the cam gears, had it advanced and retarded, still no resolution.

Set up:
stock LS sleeves, 81.5mm bore, wiseco pistons, eagle rods, acl bearings, new seals, oem ITR oil pump, water pump, timing belt.
b16 head w/ blox b cams and blox valve train. skunk 2 cam gears.

Weird thing is, I was street tuning a couple of months ago with some GSR cams. everything was fine during the street tune (meaning no vtec issues). Swapped the Type Bs in, and went to the dyno.

Any ideas what you guys think it may be? If you need any more details on the set up, i'll be glad to post it up. The shop is thinking its the cams, I'm still guessing its some sort of electrical issue, and I have a friend who think its an oil pressure problem.

pic of dyno chart:


picture of my headache

 

does the car hold boost all the way up to redline?

 

holds boost all the way to redline. only issue is that it takes a huge **** when vtec hits.

 

thats what happens when you lag on your car
jk jon , hope you find your problem

 

try swapping the cams out back to the gsr's then work from there.

 

and here's a video of how it sounded (at its worse). There were times when the car ran smoothly on the dyno (meaning no sputtering), and there were times when it sputtered in vtec, then stopped.

http://smg.photobucket.com/alb...1.flv


and here's a video of a clean run (even though power was still lost at vtec)

http://smg.photobucket.com/alb...o.flv


Modified by Outkast95LS at 1:57 AM 1/3/2008

 

good luck jon, i know a couple of people who have had the same problem. usually was oil pump but i guess if its a brand new oem type r i doubt thats the case

 

bent oil pickup maybe?

 

I highly doubt its an oil pressure problem. Mainly because when I had my gsr cams in, vtec hit fine... and I don't think swapping in cams would change my oil pressure in any way.

 

i was thinking bent pick up too.. maybe a passage is clogged or somethin.. you check the screen on the solonoid?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 408wdy &raquo;</TD></TR><TR><TD CLASS="quote">i was thinking bent pick up too.. maybe a passage is clogged or somethin.. you check the screen on the solonoid?</TD></TR></TABLE>

the screen on the solenoid was a bit dirty, we cleaned it up and it still had issues. We then tried another solenoid (one with an oil pressure switch, and Brandon wired it up to the ECU, and still had problems)

 

hmm.. change the cams back and see what happends. hope your problem gets resolved fast

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 408wdy &raquo;</TD></TR><TR><TD CLASS="quote">hmm.. change the cams back and see what happends. hope your problem gets resolved fast </TD></TR></TABLE>

thanks. that's what i'll probably do, just change the cams out. But my main question is, realistically, how would a set of cams (even after the cam gears have been played with) cause the vtec to drop down like that? Is it even a realistic option to suggest that the cams are the culprit?

 

maybe the vtec lobe is too harsh?

 

possibly cams have too much duration, lowering your dynamic compression too much?


Modified by Wraith at 4:07 AM 1/3/2008

 

bump for resolution. i am thinking cams or bad gas.

 

im wondering what size injectors he is using.. thinking the vtec lob on the cam is too harsh. the injector cant get enough fuel in there for the duration that is stays open..

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 408wdy &raquo;</TD></TR><TR><TD CLASS="quote">im wondering what size injectors he is using.. thinking the vtec lob on the cam is too harsh. the injector cant get enough fuel in there for the duration that is stays open..</TD></TR></TABLE>
hes running 880cc injectors. we were discussin this through PM last night for about an hour. we have ruled out ignition(wires/sparkplug/etc), air filter, sensors, vtec solenoid and ecu(says he used redzone's setup). only thing left would be either the cams itself since he didnt have the problem with the previous cams(gsr), or a bad tank of gas.

the splutter sounds almost exactly like its pinging so that could be it as well. at this point, anything goes. i used to have the same problem on my turbo setup but only once every 2days or so. it might just be bad gas since we couldnt figure what else could caused it. i had CTR cams.

 

ahhh.. put some c12 in there then

 

is it a possibility that the blox B cams are bit too big for boost? blox B's are equivalent to skunk stage 2's correct?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 408wdy &raquo;</TD></TR><TR><TD CLASS="quote">ahhh.. put some c12 in there then </TD></TR></TABLE>
i suggested he try to add a gallon of race gas or some sort of octane booster(toluene). i believe hes going to try something off the shelf today.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by onepoint6i &raquo;</TD></TR><TR><TD CLASS="quote">is it a possibility that the blox B cams are bit too big for boost? blox B's are equivalent to skunk stage 2's correct? </TD></TR></TABLE>
the blox b/stage 2's are fine for boost, infact they make great power compared to CTR cams as long as you get the overlap dialed with the gears. he "could" have a bad set of cams tho.

 

What are you using to tune? What do the maps look like at those RPM points? It looks primarily like a tuning issue rather than a mechanical one.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Padawan &raquo;</TD></TR><TR><TD CLASS="quote">What are you using to tune? What do the maps look like at those RPM points? It looks primarily like a tuning issue rather than a mechanical one. </TD></TR></TABLE>

Using Crome pro to tune. I ruled out a tuning issue mainly because the tuner(s) that tuned it are very reputable and would think they could clear up the issue during our dyno session. I'll try to see if he can send me the bin file and i'll post it up.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by rebo0t &raquo;</TD></TR><TR><TD CLASS="quote">

the blox b/stage 2's are fine for boost, infact they make great power compared to CTR cams as long as you get the overlap dialed with the gears. he "could" have a bad set of cams tho.</TD></TR></TABLE>

i see

 

r u tunning on 91?