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Thread: VE slower with both hi cams??

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Posts: 1-8 of 8
2012-03-22 01:11:45
#1
VE slower with both hi cams??
Hey guys I'm really hoping someone may be of assistance here as this is doing my head in!
Here's a brief rundown of what's happening: I have been using the P12 solenoid on my P11 sr20ve for the past 9 months and as far as I knew it worked fine, the only issue being the car was about 15hp down on the power it should have been making.
So anyways, the other week I find this thread just randomly http://www.sr20-forum.com/vvl/15110-cam-angle-sensor-vtec-actuator-p12-onto-p11-head.html and suddenly it seems as though I have only had my exhaust hi cam kicking in! Well there's my lost hp I figured. So I took the P12 solenoid to a machine shop, got a P11 gasket and got him to mill that groove into the solenoid housing so la de da i should now have i-vtec
BUT, here's my question for you guys, is it possible/likely that my car is now slower than it previously was on lift?? Because it certainly feels that way.
Difference isn't huge, barely noticeable but I am 99% sure it's slower than it was on just exhaust hi cam.
The reason I ask is because I did have the car tuned when it just had exhaust hi cam, so now with the intake cam kicking, could it mean that my afr's are now all over the shop and hence, slower on lift?
I know that whacking it on a dyno will most likely answer the question but atm I don't have the time or money to spare, so I'm asking you guys
Any help would be greatly appreciated, sorry for the long post!

Cheers, Dan.
2012-03-22 13:37:42
#2
you're gonna need a re-tune.
2012-03-22 19:10:52
#3
Is it possible you are a little bit slower? Yes! You were tuned for a specific set-up and then you changed the setup, so your tune is now not optimal. Like Teal97 said, you WILL need to re-tune for the change. As far as how it would affect you AFR's, I don't have enough tuning knowledge to say by how much but it would change your A/F ratio, after the cam switchover, for sure. You also need to get a wideband too! After I put my tuneable ECU in, I went 3 weeks without a wideband. When I finally installed a wideband I realized I was running insanely lean all over the map, especially when cruising on the highway. I was getting readings over 18 at times. I am convinced that those 3 weeks played a large role in my engine loosing 15 points of cylinder compression across the board.

If this was my car here is what I would do. Before I bother with a re-tune I would pop the valve cover and check the small lobes on the intake cam for excessive wear or minor damage. I would also pull my plugs and check them too! If everything there appears to be okay, I would then do a compression test. If you had regular VE cams and were spining the motor to 7500/8000 rpm or if you had N1 cams and were spinning the motor to 8500/9000 rpm, I would be a little bit worried that you may have floated an intake valve or two. These engines were not designed to have the small lobes open and close the valves at that high of an RPM.

Having been through a year of screwing around with my VE engine, take the advice and make sure everything is okay before you go hammering the gas pedal around town! Hopefully everything is okay, and more than likely you will be fine if everything seems fine but it is better to be safe than sorry. Lots of guys on here have driven around with bent valves on these engines, some without even knowing it.

If I was in your situation (you said time/money is tight), I would save-up the 200-300 bucks and after checking all of the above mentioned stuff, I would than get it re-tuned.

If you seriously can't afford the tune, disconnect the vvl solenoids and stay below 5500-6000 rpm until you can afford it.

This is just what I would do of course!

Good luck!
2012-03-22 23:39:01
#4
Alright, thanks very much for the replies guys

B15NEO: Thankyou so much for taking the time to write that mate! I will hopefully be able to go through most of those steps this weekend!
And yes a re-tune is absolutely happening and hopefully in the next few weeks too, so that will be excellent. I just hope these tuners know more about VE's than the last guy I took it to...

Cheers fellas!
2012-03-24 14:46:10
#5
Do you have your dyno sheet from when the tuner tuned your car without the intake switchover? I am very curious to see what the graph looks like and what the tuner was seeing too!!
2012-03-25 07:52:21
#6
Yepp sure do, here it is


What do you guys think?
2012-03-25 07:58:07
#7
This is just with the exhaust cam switching over? I forgot the formula to convert from kw to hp but that number should be around 145hp.

Do you have the AFR chart for this dyno?
2012-03-25 10:19:07
#8
Yeah that's just the exhaust cam kicking.
145hp is spot on mate. Pretty low right?
And yes thats the AFR on the right hand side of the graph which corresponds to the lower line
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