Hi guys

i am running a forged vq35de with a gt4094 single turbo 1mm oversize valves and 8.5cr and custem plenum on the dyno the engine makes great torque 600ftpounds 18psi boost but the horsepower falls off at 6000rpm the cams are standed i think that whats holding the engine back is this normal for the standed cam? what is a good cam to make power to 7000rpm?

 

Look at the Brian Crower Stage2 cams.

 

BC Stage 2!!!!!

Stock cams peak at about 6250rpm....then they drop like a rock, I got the same problem

tom

 

Another option is the JWT C2. Here is the comparison:

JWT C2
261 deg advanced duration
225 deg duration at 0.050" lift
11.58 mm lift
117.5 deg Lobe Separation Anagle

BC Stage 2
264 advanced duration
222 duration at 0.050" lift
10.82 mm lift
Lobe Separation Angle???

EDIT: Another option...

GTM Stage 2
272 advanced duration
232 duration at 0.050" lift
11.00 mm lift
Lobe Separation Angle???

 

how exactly does jwt determine lobe seperation angle?

 

Here is a link to cam basics that will be helpful to those interested in this subject, and it includes a description of cam lobe separation:

http://www.wallaceracing.com/cambasics.htm

JWT does not specifiy the cam lobe separation angle per se, but they do specify the timing information for the cams with the intake phaser off. From this data, the cam lobe separation can be determined (assuming symmetrical lobes). If the lobes are not symmetrical, then the computed cam lobe separation angle is only an approximation.

EDIT: I have confirmed that the JWT cam lobes are symetrical for their VQ cams.

 

^ Terry congrats on the mod role. Also thanks for the good link.

 

Thank you!

 

so if i understand your post correctly,your saying that jwt uses a static measurement for their lobe separation?

with vvt motors how is this useful information?

it's like a snapshot of infinitely variable lobe sep......i ask you sir.....why?


btwy congrats mr mod

 

Why not BC stage 3?

They are designed for forced induction. There's a thread showing 50whp gain in midrange alone.

 

^^^^

It's definitely an option.

 

I would assume that you would give up some mid-range and low rpm driveability (BC's site says the stage 3's are a race application....whatever that means these days though lol).

I'd guess the stage 3's really want to be up higher in the rpms......but the OP does have a pretty decent sized turbo so that may be the plan already.

Tom

 

JWT did not provide the measurement. I calculated the lobe separation based on the published data.

Remember, on the VQ35DE, phasing is only applied to the intake cams. However, the intake cams start out fully retarded, advance, and then are fully retarded to their original position in the upper rpm range. The cam lobe separation angle and duration are helpful for determining the valve overlap at idle and at high rpms, which provides an indication of how the motor will idle and how well the motor will breath at high rpm. Cam lobe separation/valve overlap do not tell the entire story, though. Exhaust back pressure/reversion is another issue that must be considered at high rpm, etc., etc. Nonetheless, knowing cam lobe separation/valve overlap can be useful in selecting other components for the build.

For example, on my build, I selected 0.64 A/R turbos instead of 0.86 A/R turbos because I want the turbos to spool faster. Also, I am moving from the C2 cams to the C8 cams. Knowing the C8 cams have greater valve overlap puts me on notice that if my exhaust back pressure get's too high, reversion will be a greater concern with the C8 cams as compared to the C2 cams. Had I stayed with the C2 cams, I wouldn't have much concern. Nonetheless, I want the greater power potential of the C8 cams. Therefore, when I tune my car, I am also going to monitor the ratio of the exhaust pressure (pre-turbo) to the intake pressure (MAP). If the ratio gets too high (maybe above 1.5 or so), then I will have an indication that I should go back to the C2 cams or get turbine housings with a larger A/R. If the ratio is acceptable, I'll know the cam/turbine housing combination is good for my goals.

For those that are interested in how and why VVT is implemented, here are a couple of links that provide some general information:
http://www.superstreetonline.com/tec...shi_mivec.html
http://www.g20.net/forum/showthread.php?t=41446

Thank you!!!

 

hi there seems a lot of choices i no that my turbine backpressure is about 1.5 this engine is a race engine for circuit racing might need a bigger ex housing. might look at the c2 as a wide powerband is important

andrew

 

That was going to be my question.. what size exhaust housing and ebp. Given that backpressure, an aftermarket cam still won't alleviate the problem at hand (choking).

 

hi by memory i think .92ar i have 3psi boost 2500rpm what shows its a bit tight at 18psi there is 25-26 psi of mainfold pressure at 5900 rpm what sort of power can u make with standard cams?has any body ran a gt4094 i have no room for twins my goal is 700hp thanks andrew

 

It tool Hal 28psi using Q16 race gas on a 4202r to make 772whp.

http://www.injectedblog.com/2009/08/...-350z-testing/

you're going to have to string that 4094 out pretty good to get 700.

 

thanks for the reply i have a 1.19 ar housing might try that one. this engine was run on a engine dyno so 700 should be around 600ish wheels so far i have made 630hp and 600ftp torque on 18psi new to these engines over here very few people run them