whats up im new to vtec i just changed my b18b into lsvtec my vtec kits in at 5200 rpm but it dont really start scurry-ing down the road until about 6700rpm.

could it be that once the vtec engages it leans way out, then it takes 1500rpm to richen its self up?

would a fuel pressure regulator solve this? or is that how vtec works

thanks!!

 

It depends on the ECU you're running...what head you used...and other modifications. Judging by the "scurrying" comment, I doubt Vtec is even engaging at all. Vtec didn't engage for me with my Ls/Vtec until I swapped my GSR ECU for a chipped P28 (thanks IH8Ricerz). The GSR ECU wouldn't allow Vtec to engage because I was missing a knock sensor and crank angle sensor, which were eliminated by the P28 ECU. Give us a better description of your setup and we'll be able to help out more

 

its a chipped p28 ecu '91 jdm b16 head on 95 ls block jdm ctr tranny all stock except flywheel, intake and the 2 1/4 exhaust and 4-2-1 header. vtec does kit in at 5200 you can hear it and it does not start to pull any harder until 6700rpm then from there it will pull very well until 8000rpm

 

the vtec kicks in around 4500, what your feeling is the secondary butterflys opening. And at stock they open at 5800. At least on my GSR they do, dunno about ls/vtec. But I'd assume it was the same. Anyway, the secondary butterflys don't help it pull anymore and the pulling at 6700 is just the engine revving. Its a high rev engine and thats where all the power is. Though I don't know your car specifically and theres a chance that the VTEC isn't kicking in at all. but it sounds like it is and your just listening for the wrong thing.

 

does anyone see gsr in this paragraph? its a chipped p28 ecu '91 jdm b16 head on 95 ls block jdm ctr tranny all stock except flywheel, intake and the 2 1/4 exhaust and 4-2-1 header. vtec does kit in at 5200 you can hear it and it does not start to pull any harder until 6700rpm then from there it will pull very well until 8000rpm

how do you guys tell someone when there vtec kits in or if it even does??????i dont have a gsr so there for i dont have no secondary butterflys. and i dont care what they help or dont help i will say it agian VTEC KITS IN AT 5200RPM IT DOES NOT START TO PULL ANY HARDER UNTIL 6700RPM is this how it works or should it start pulling harder as soon as vtec kits in

 

vtec shouldn't be an "OH MY GAWD" change over. It should be smooth. Judging from what's going on, I'd go and get the engine tuned, or at least dyno'd. If I had to guess, I'd say that your fuel (rich or lean, I don't know) is what's causing the problem. Another guess would be that vtec is engaging too early for your setup. I'm not sure, just trying to throw some stuff in the air. Good luck though

 

ok let me rephrase my question people seem to be taking it the wrong way im not a moron and i dont expect the hp to go from 130 or so to 260 as soon as vtec kits in. so now my new question is for vtec owners does your car start to pull harder once vtec kits in or does the motor have to wind out a little more before the hp jumps up.

thanks

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by aziz93 &raquo;</TD></TR><TR><TD CLASS="quote">ok let me rephrase my question people seem to be taking it the wrong way im not a moron and i dont expect the hp to go from 130 or so to 260 as soon as vtec kits in. so now my new question is for vtec owners does your car start to pull harder once vtec kits in or does the motor have to wind out a little more before the hp jumps up.

thanks</TD></TR></TABLE>

I've got ITR cams in my LS/VTEC and yes, there is a slight to moderate increase in pull... Nothing tremendous, but you can tell something has changed... However, with you stating that it's a 91 JDM B16 head, do you know if the car it came out of was automatic, or did oyu get a complete swap, whatever...? Auto VTEC cams are crap, and you won't feel and increase until you get to about 7k, where obviously it's gonna pull...

Bottom line is get a tuning device, Hondata, VAFC, something and get to a dyno to find out why it doesn't pull correctly...

 

When I had a GReddy EVO exhaust, I couldn't hear VTEC crossover at all. I could only hear the secondary butterfly's opening at 5800 RPM.

When I had a Tanabe SRM exhaust, it would be really loud when VTEC crossed over and I couldn't hear the secondary butterfly's open.

But the car didn't start to pull hard until the 6000 RPM range with either exhausts.

 

ok i hooked up a autometer air/fuel ratio guage and took it for a ride. the a/f mix was perfect to slightly rich until vtec kicked in (5200rpm)then it went way lean, out of the meters range, then climbed up to almost perfect a/f mix still a little lean then at 6700rpm it right to mid rich section and started runnin like a raped ape!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by aziz93 &raquo;</TD></TR><TR><TD CLASS="quote">ok i hooked up a autometer air/fuel ratio guage and took it for a ride. the a/f mix was perfect to slightly rich until vtec kicked in (5200rpm)then it went way lean, out of the meters range, then climbed up to almost perfect a/f mix still a little lean then at 6700rpm it right to mid rich section and started runnin like a raped ape!</TD></TR></TABLE>


That's just a lazer light show... Get a wideband...

 

cant u use a p72 ecu for a ls vtec