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Thread: OST-037: Under Pressure

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Posts: 101-110 of 128
2016-01-28 18:32:49
#101
This why I was trying to get you to get some before flow numbers lol
2016-01-29 21:51:06
#102
Well.... as I've already told my client.... I've got some good news.... and some bad news.

First the bad news... #1's valve seats will be replaced on my dime between the new guides, and a bit zealous on the seats, there is not enough throat cut and the numbers reflect that......

.100 - 72cfm
.200 - 135
.300 - 169
.400 - 184
.500 - 195

Now to be honest the high lift is still an improvement over the stock numbers from MotoIQ(by 20 cfm).... but there is just too much loss in the low#s.... and it doesn't compare well with the ported numbers from MotoIQ.


As a comparison here are the other 3 exhaust ports...

.100 - 75cfm
.200 - 144
.300 - 177
.400 - 198
.500 - 206

These last three line up well with the MotoIQ plot.


So new seat are to be installed in #1 next week.....



Intake numbers still to come........ I'm confident that the intake side will not disappoint........


more to come........
2016-02-01 17:00:20
#103
intake #s.......

.050 - 43cfm
.100 - 87.5
.150 - 123
.200 - 159
.250 - 190
.300 - 214
.350 - 232
.400 - 243
.450 - 251
.500 - 257


Why?


The head goes back out to get #1 exhaust seats replaced.... but in the mean time.... Why are the low lift numbers so good, and yet the higher lift values only so, so???
2016-02-01 17:14:51
#104
coanda effect.
2016-02-01 17:35:53
#105
Originally Posted by zeneffect
coanda effect.





Or could be valves(either, or both)......???

I showed the exhaust valves earlier... here are the intake valves....





and a little superimposition




The OEM valve is more of a tulip shape, the Supertech is more nail head shaped. Once the head comes back, I'll toss in a pair of OEM intake valves and rerun the intake side to see what, if any differences I get.....


more to come....
2016-02-02 03:56:29
#106
Last edited by zeneffect on 2016-02-02 at 04-24-49.
2016-02-03 01:15:42
#107
Lighter valves, ftw.
2016-02-04 15:56:22
#108
I would like some additional eyes....

I'm looking for a spec in the manuals... I can't seem to find (looked too many times....) The spec I'm looking for is known as "valve protrusion". As an example, here is a scan of valve protrusion for a Mazda Miata





Knowing the protrusion before I assemble will allow me to know if the valves may need to be tipped..... so if any new sets of eyes can find this spec for the SR20VE, I'd be grateful.....




more to come......
2016-02-05 16:39:27
#109
Its not you, its simply not there. In fact... I cant find that spec in ANY ve FSM.

Guess the only way to find out is to install a valve and a cam, then see what the shim clearance is. if clearance is too tight with a 2.7mm shim then valves can be tipped a max of .2mm according to FSM
2016-02-07 03:09:06
#110
Originally Posted by zeneffect
Its not you, its simply not there. In fact... I cant find that spec in ANY ve FSM.

Guess the only way to find out is to install a valve and a cam, then see what the shim clearance is. if clearance is too tight with a 2.7mm shim then valves can be tipped a max of .2mm according to FSM


I may have found a "workable" solution...... Nissan Valve Springs
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