Thread: a good turbo ve street cam for 7500-8500rpm

Ok here is some info i have compiled

sr20ve standard cams are:
Low lobe in center angle: 110deg
High lobe in center angle: 104deg

now all tomei cams are: 110deg on all their intake cams for non vtc

so if i retard 6 deg my high lobes will be the same as tomei centre lines for cams ranging from 256-270deg where 20ve is 264in and 268ex

now to the ex side

tomei non vtc is 115 deg for all their cams

now standard ve specs are:

Low ex lobe center angle: 122deg
High ex lobe center angle: 114 deg

so all i really need to do here is retard the ex a deg or so bringing the total decreased overlap to 5deg over standard. which should be ok for the low lobes to operate properly.

This will be to get the same specs as tomei cams on high lobes, but obviously each engine will have its own timing. Basically my point is that i dont see a big problem with overlap on standard sr20ve cams.

What i do see is a problem with the low ex lift of 6.6mm, i can see it choking the low to mid range torque. although there is a lot more duration on the low ex, their is also a fair bit more advance on the lobe too.

now lets look at the 20v specs

(20V)Intake cam Low duration: 228deg Low lift 10.10mm
Low center angle: 114deg
High duration: 278deg High lift: 12.00 mm
High center angle: 114deg

Exhaust cam
Low duration: 244degLow lift: 8.30mm
Low center angle: 106deg High duration: 280deg High lift: 11.15mm
High center angle: 108deg

There seems to be less advance on the intake decreasing overlap but a lot of retard on the ex on these cams compared to sr20ve's and even 16ve's, as 16ve's overlap seems to come more from the huge amount of advance on the intake. The n1's run closer to a 20v ex centerline with a 20ve centerline

However the interesting thing about the 20v's here is that the 20v would make a easy to tune turbo cam as the low and high lobe centrelines are very close together, although there is a heep of overlap in these cams (compared with 20ve's), its nothing that cant be tunned out with cams gears buy just retarding the exhaust. I would assume 115-120atdc would be best and you could probably advance the intake a little

now these centreline figures work on the bigger lobes, ie tomei procam, jwt c2, jwt c3

actually for reference:
c2 in 111 ex 117
c3 in 111 ex 120.5


lets assume we set to
low in 111deg
high in 111deg

low ex 116deg
high ex 118deg

the question is if we set to these fiures what effecxt woul it have on the lows?

my ultimate turbo cam would honestly be constructed from copying lobes that have been proven, and would be something like this:

20v in low lobe 20vet ex low
tomei procam 270deg high
jwt c2 high ex

the problem here is that i dont know what the 20vet low lobe centreline is.i have seen low 20v in and 20ve ex work before though. Went pear shaped on cam switchover, even though the low and high 20v in centrelines are the same, there is a whole lot of overlap added from the 50 degrees more duration on the in, and a ex lobe with some retard would be needed to match them.

Anyway the specs for the cam would look like:

INTAKE CAM:

low 228deg 10.1mm lift
Low center angle: 114deg

high 270deg 12.5mm
high center angle 110deg

EXHAUST CAM:

low 244 11.3
unknown angle but i assume it will be advanved which will match that high lift

high lobe 275 12.7mm lift
high center angle 114deg


now the problem i see with this cam however is valve lift from the ve on the ex. i think i read somewhere that 12.7 is ok, but have also read 12.5 is the limit. even still i am sure a slight adjustment could be made

now if we use the vet low lobe, should we change the centerline? what would be best? or should we just extend the 20v ex lobe to 10.7mm?

anyway sorry for the long post, and feel free to argue and criticize any comments made or calculations i have fudged. discussion = good

Well, making your own cam is a start. I have tried to discuss previously that the reg VE cams are not a good choice for turbo, as you have to rev too high. High overlap is not wanted in a turbo cam.

The problem I saw with the 20ve cams is that if you start changing cam timing to compensate for overlap on the big lobes, you inadvertantly change the cam timing for the low lobes and it hurts power. I tried taking out 20* overlap on the stock sr20ve cams and it felt really good above 5k, but getting there was a whole different story. It lost a ton of bottom end power.

I think this cam profile you have described would be good, I am a fan of high lift
Regardless, overlap is going to be the deal breaker here. We need to try and stay under 40* of overlap MAX. Integra type R cams only have 28* of overlap and very high lift, and the honda boys love them for turbo.

It seems like nissan chose these profiles for the engine to compensate for softer valve springs, soft valve springs get better mpg and emissions. That's kinda what nissan was going for when they developed VVL.

^^^ yes i have read a lot of your stuff regard standard vet vs sr20ve cams and its all great info. But your testing was done on a log manifold. Would be interesting to see what results you get with standard vet vs sr20ve with your new manifold.

obviously custom made cams would be best though, i think the profiles i have listed would be good.

Saw a VE+T on the dyno last night. He had Stock SR20VE cams and our old friend the Log manifold. Power peaked at 7200-7300 and fell off hard at his revlimit of 9k. It's was a specked out turbo rated at 600hp (prob a 60-1 or something close to it). I really think the log manifold killed it big time he made like I think 438-458 max at 24psi I think. He had a JWT ecu, 72lb injectors, race gas, Z32 maf. He made a little more on de with the same manifold but O2 induction intake manifold.

Log manifold is a no no on the VE. I think over lap and log manifold do not go hand in hand.

I have seen about a 70 WHP change from changing from log to individual runner.

Just for comparison. My friend Nick made 460 WHP at 18 PSI with a equal length manifold and GT30R turbo. He was running a JWT ECU, 300zx MAF and 740cc Injs at 4 bar.

At 7800 RPMs the car was still pulling up, but silly JWT put a rev limiter on the car at 7800 RPMs so we dont know where the peak was. This was after I told them not to put a rev limiter on the ECU.

Nick was on stock 2.0 cams right Dre?

Yes he was.

Cool.

2.0 cams seem to work great. That's what I will be using. I am curious to see what a good designed turbo cam woudl do for the VE.


My cousin back home has a high whp Honda and he saw better gains with stock cams then he did with aftermarket cams. I wonder if the VE is the same.

Sr20VE and 20V cams are the best turbo cams.

That was a theory I had long before he put his motor together but he had to learn the hard way.