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Thread: VET Cams

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Posts: 31-40 of 41
2009-02-18 19:33:14
#31
Originally Posted by Andreas

I am not talking about a SR20VE cam, I am talking about a SR20VE 20V cam.


Really? I thought you were talking about the VET cam:

Originally Posted by Andreas
It was tested by Clark Steppler at JWT and lost power when they switched the exhaust cam to the high lobe and that is with VET cams on the intake and the exhaust.


I understand that you've also remarked that the 20V cams would be preferable. But if it turns out that the VET's exhaust cam has the same high lobe as a 20V, but the better low lobe, then wouldn't that be the better option?


Originally Posted by Andreas
Also, you were running the low lobe on the exhaust side when did this test, So when you went to the standard VE cam which is bigger than the VET intake cam, you of course will make more HP.


No I wasn't, as per my earlier post:

Originally Posted by more_fasterer
I've replaced the above exhaust rockers with some out of a VE, so the exhaust high lobe now actives. Hence the question in the original post



Originally Posted by Autech
The duration on the VET exhaust high cam looks extremely long. Too long for my personal liking of cams that ive seen. The ramprate by eye is huge, almost a complete drop, and if the rocker ratio still reflects this sort of valve behaviour - to me from my background of learning it wouldnt help with exhaust gas flow to keep the turbo spooling properly. It would be very on/off.


Good stuff. That's the sort of thing that I simply can't tell with my current setup, as (a) there's no point revving past 6500 because there's no torque, and (b) the standard turbo spools so quickly anyway. If you're happy to send your cams away to be measured, then all the better
2009-03-02 08:00:34
#32
Originally Posted by Andreas
Its going to lose power as it has been done before.


Originally Posted by Andreas
Well if you have the VET cams and have switched them already all you need now is some cash to waste, put it on the dyno and switch over the exhaust cam.

The we will know.


Depends on the setup though cause every engine is different, jsut like people claims that the N1 intake would make extra power cause it worked for them bu others lose power.

I have the VET cams in my N15, I gotten the exhaust cam pulsing on and off at low revs making the turbo wind up quicker. Permanently on exhaust cam from 6000 revs now. Power gain was 31hp and the exhaust heat probe showed up colder on the dyno. Turbo is an XTR garret hybrid turbo. very happy with the results i got, despite the hassles
2009-03-02 09:45:23
#33
Well feel free to test on my engine once it's built... we just need to get it done Kieran :-p
2009-03-02 11:51:39
#34
Originally Posted by VeryQuikSSS
Depends on the setup though cause every engine is different, jsut like people claims that the N1 intake would make extra power cause it worked for them bu others lose power.

I have the VET cams in my N15, I gotten the exhaust cam pulsing on and off at low revs making the turbo wind up quicker. Permanently on exhaust cam from 6000 revs now. Power gain was 31hp and the exhaust heat probe showed up colder on the dyno. Turbo is an XTR garret hybrid turbo. very happy with the results i got, despite the hassles


Explain how your controlling the exhaust cam pulsing on and off?

If yoru making 31more whp im going to assume that your exhaust temp would go up!

Never knew there was an SR20VET in sydney in an n15....
2009-03-05 06:56:33
#35
The engine computer tune is pulsing the exhaust cam but it makes the car backfire a bit.

not sure on the theory too much but i seen the dyno logs on two seperate mainline dynos. manifold presure not spiking and heating the manifold as much may explain it though. I might ask my dad, he is a well known ozzie engine builder and might be able to explain it.

I moved to sydney from sunshine coast to live with my sister. its a red n15 sedan with a V+t setup. i bought the car through a friend from a guy who setup it in kempsey. the turbo is a now a XTR SR3040 from gcg with 18psi daily and 25psi for balsts through the gorge.

i had to upgrade the brakes once i moved down here, the mechanic thought the brakes I had were too small. stop awesome now
2009-03-05 07:32:02
#36
The only time I ever heard of a VVL pulsing on and off was when I tried to activate the VVL with a stupid shift light, and I didn't know that specific shift light I bought blinks, so the VVL did that also Lol I didnt know if I should laugh or just get angry about it.
2009-03-12 05:28:09
#37
I figured I would post this here. I got a chance to play with the VET exhaust cam switchover. I started out by lowering the exhaust switchover and reading the vacuum/boost gauge. No surprise, there was about a 3in drop in vacuum when the cam was switched at idle. Went from 19" to about 16" and a very rough idle.

I then switched it up to 2000rpm or so. It built boost 12psi by 3800rpm. Not bad at all. When boost hit, it seemed to hit a lot harder and all at once in the lower gears. The butt dyno doesn't tell much of a story. It did seem to hit a lot harder when the exhaust was switching over early. There is also a notable exhaust tone change with the switchover. Something that is absent with just the intake changing.

The car pulls really good. Very strong. I'm sure boost will hit a lot sooner when I am done with everything else.

I am going to post dyno sheets up when I get the chance so we all can see what actually happens when the exhaust changes. I would love to see a gain, but I am skeptical. All the exhaust flow in the world won't help much with a crappy log manifold. But I will def get some dyno runs soon!
2009-03-12 05:36:59
#38
cool. when do you normally hit 12psi buy?
2009-03-12 05:56:04
#39
I would say around 4200rpm. I have an exhaust leak pre-turbo so I normally don't hit full boost until 4800rpm.

It isn't a huge difference. The dyno will tell a better story than I can though. My butt dyno needs calibrating.
2009-03-12 05:59:16
#40
Good work, keep us posted
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