Thinking about increasing the boost on the vortech before my tune coming up.

I'm with the stock kit now that makes b/t 7-8 PSI and want to get it to 9-10 PSI.

I have the revup kit for the g35.

I'm not really sure what cogs I have now but I do know I have the 3.12 pulley.

Now should I go with a cog setup with less teeth or should I go with a 2.87 pulley to get to where I want to be?

Thanks.

 

if you went with less teeth on the cog set up, you'd have less boost. the cog pulley is the one on the opposite side of the 3.12 pulley that you have. now if you went with a smaller jackshaft pulley (the one on the s/c) you would spin the blower faster and make a lil more boost.

my recommendation to you would be to either try out the 2.87 pulley and see where that puts you. or try out a larger cog pulley and or smaller jackshaft pulley and see where that puts you.

either way, dont forgot to pay attention to the RPM calculator on vortech's website. you do not want to over spin your blower and run into problems like bearing failure etc.

good luck with your goals!

 

You can go to a smaller serp pulleyy , a larger cog pulley on the jackshaft , or a smaller cog pulley on the blower it self .

 

which do you feel would be the easiest?

I'm leaning towards just picking up the 2.87" pulley since that would be the simplest to change.

I did learn a bit more about my revup setup and I think it runs a 34/28 setup so increasing it to a 34/30 or 34/32 stepwise would give me gains in boost as well correct?

I think what I'll do is order the 2.87" pulley and bring it to my tuner to just have them install it and tighten the belts just prior to our tuning session.

My goal is to make 340 rwhp and 310 rwtq and I think I'm able to achieve this by buming the boost just a tad more. I'm sure the tuning will possibly bring me to this goal just the same way since currently my best runs on a dynojet have shown 322 and 285 tq on the stock vortech tune with the unichip with the car running extra rich in the mid to high 10s almost the entire time until after 6000 RPM where it leans out.

all of your advice is greatly appreciated.

 

my mistake. it looks as though the revup comes with a 34/32 and according to the Vortech FAQ switching to a 32/28 would bring me more boost.

I guess at the end of the day the cost of one serp pulley vs. the cost of 2 cog pulleys makes the serp pulley a simpler fix for me.

 

Going by this formula my 34/32 setup with a 7000 RPM redline and a 2.87 impeller speed would be around 52,750 RPM which is waaaay too close to the max impeller speed of 53,000 RPM.

It seems I really can't upgrade my boost at all without destroying this blower and having it reach its maximum impeller speed.

Any ideas on why this is?

 

welcome to the down side of owning a vortech sc trim blower.

see what happens with impeller speed if you just change the jackshaft pulley on the supercharger. that may net the same results as changing just the 2.87 pulley

 

you know what, I think I'm gonna stick with my stock revup setup.

gonna get my tune

THEN

gonna hope to be at my goal of 340 rwhp and 310 rwtq

though the tq will definitely not happen I think the hp goal is plausible.
I'm still running stinkin' rich up until 6000 RPM with AFRs showing 10.6-10.8 all the way. It gets closer up top but even then I'm running about 11.2-11.4 at the highest.

a tune will smooth that all out and hopefully I'll make it to where I want to be. if not, so be it.

I think there's something to be said about leaving good enough alone...

thanks for all the tips though, I'm sure this thread will be useful to someone later down the line.

 

your goal is 340whp and u dont think the stock pulley will make 340whp? I made that with the 3.33 pulley and I was running pig rich. If u trying to get 380whp then u will need the 9psi pulley for sure.

 

thanks, I'll try with my current setup first and see where that takes me.

 

I will go ahead and promote the 2.87 pulley, going from untuned 3.33 to tuned 2.87 is literally like bolting on another supercharger.

 

just put the 2.87 pulley on and get it tuned. keep the cog set up as it is. yes you'll be close to your max impeller speed, but you wont be over it. i made 405 whp with my 3.12 pulley set up...... you should make way more than 340 whp.

 

The only issue is that I'm using stock injectors on a fmu with aux fuel pump setup. The injectors may be maxed if I put on a 2.87 pulley and attempt to make 400. I'm trying to find some 440 injectors now to get it all going. If I can then ill be good to go.

 

i have stock injectors and stock pump. i used the vortech full kit which used the inline pump and FMU. made 405 whp easy. it was rich as hell. ran great for a few thousand miles. then i took it off. just go for it. my kit makes 10.1 psi at redline. i think you'll be fine dude.

 

buy at least 550cc or 600cc injectors with the 2.87. depending on your mods and tune your looking around 380-395whp. who's tuning your car.

 

fastlane inc. is going to tune my car. they're the only unichip tuners in town and from his reputation I think the tuner there is solid.

 

on my rev-up kit i installed the 2.87 serp,32 j/s cog and 28 s/c cog " non rev-up configuration" this made the boost come in quite a bit earlier in the rpm band. i recommend this setup but i had to add a custom mounting plate and additional idler pulley for the cog belt due to the rev-up kit having a shorter cog belt than the non rev-up kit. if this is not done the cog belt will shread under heavy loading during dyno pulls.

 

The only thing you need to upgrade is the injectors if you wanna go 2.87. I bought some cheap used denso injectors from a member on this board and they worked fine.

 

were the injectors a pita to install. I have a 04 with 3.12 pulley and wanted more power, is there a big difference between the 3.12 and 2.82.

stock injectors
tuned black box
384 rwhp

 

injectors are simple to do, pop the intake manifold off and there all right there