Have opportunity to buy Vortech 2.93 pulley in Anodized red for about $40 unused but need to act quickly.

Have stock Vortech S/C install i.e. base SplitSec map etc.
What are the issues with the smaller pulley other than it raising boost.

i) Do I need a new belt and can I source from Vortech
ii) Does SplitSec box need a tune before install.
iii) Other issues?

I apologise for not doing a Search (I do usually) but I can make a good purchase if I act quickly.

Thanks

 

2.93 ? I think you may mean 2.87 pulley . Where are you getting it from ? Never heard of Vortech making them in red and a 2.93 size . You might want to check if it will even fit and work

 

Thanks Booger - you've made my mind up; NO SALE

Gonna do some research on 'proper' Vortech pulleys on here now.

 

The stock is 3.33....then there is a 3.12...and the smallest is 2.87 . Go to Vortech's web site to order

 

Thanks for the heads up - I was just off to measure mine on the car - saved me a job

 

I saw that you have decided not to buy the pulley, btu I will answer your question in case any others are wondering this info.

1) Yes, when you get a smaller pulley, you will need a shorter belt. Not sure if you can get one from Vortech directly, but you can get a Gates belt from any aytomotive parts store like Auto Zone or Advance.

2) You will need to retune immediately AFTER the pulley install.

3) I have heard that you DO NOT want to run a pulley any smaller than the 3.12 pulley on a stock bottom end or you will likely be running too much boost and run the risk of blowing holes in your block!!

 

Not to be picking on zachcrosen, but I've heard this comment made over and over and I'm a bit confused.

What is "too much boost" on a Vortech set up? 11psi? 10.5 psi? 10.0 psi? If I have mods that really improve my breathing capacity (i.e. really lower my boost) can I safely run a 2.87 pulley on a stock bottom end because I'm not reaching "too much boost"?

I've asked this before and booger has always tried to 'splain it to me, but I guess I'm just dense. LOL

 

I dont really know. I just know that CP RAcing told me that I DO NOT want to go with a 2.87 pulley on the stock bottom end. I have also heard the same from others. With the 3.12 pulley, I see anywhere from 7.5-9.1 psi whereas I was ONLY seeing 5.5-6.0 psi with the 3.33 pulley.

 

So is it safe to go with a 3.12 pulley on stock internals as long as you have a safe tune

 

How much power is being made on 9psi [ with a safe tune] on TT set ups ? Think of it this way . The crank , rods , and pistons on are Vortech SC cars are seing the same power as the TT set up at 9psi . The power is just being robbed by the power it takes to turn the blower .We dont make as much down low , but up top, the crank, rods , and pistons see the same stress as 9psi on the TT set ups . But we only put 400whp to the ground and the TT sets ups put down 500whp because of the power that it takes to turn the blower

 

Can the 2.87 pulley be ran safely...I think ..yes .Safely tuned and the fact that top boost is only seen in the last 1000rpms . You dont see 10 or 11psi most of the way thru the rpm range like a TT set up

 

Booger, I agree. However, at same level of boost (S/C vs TT) it would seem to me that a S/C which builds torque up progressively from 1000 rpm say (to a max at redline) would have less dramatic effect on the rods than a TT where the boost is zip until 3000 rpm say when it whams in with full force.

What I mean is that the rate of change of torque would be nice and linear (a continuous function vs time) with S/C and very large (a discrete step-change) with TT.

Still a TT will always win a drag race (all else being equal) provided the guys takes off at >3k rpm!

Plus I'm surprised it takes 20% at the top end to turn the compressor - that is high; I don't doubt it, but it is a high percentage

 

I am and have been for about 3 weeks now. I am running 367RWHP and 305RWTQ.

 

Well that what I was saying , but didnt voice it as well . But up top at red line..9psi is 9psi and will put the same stress on the internals

 

Absolutely and it does get overlooked - for S/C your obviously at that max. PSi proportionately less of the time though.

A simplistic representation which helped me (and I need help!):
http://science.howstuffworks.com/fpte4.htm

What so frustrating to me is that you guys go 'Yeah, you need a tune for a smaller pulley' and that's no big deal for you but there is zip expertise here in UK with SplitSec - still your tuners must've started from ground way back when too

 

Once you see some one work with the Split Second and the R4 , its pretty easy to understand and work with . You can down load a file from the www.splitsec.com Called [U-Tune] Take that and the R4 disk to a good tuner in your area . Let them look at it and go from there . That what I first did , .I saw him change things on it and did some reading to understand it better . Ive done it my self ever since .

 

Found it (the guide). Thanks

 

Booger,

I have scanned the guide and have a number of questions, the answers to which should enable me to get the tuner further up the learning curve (and save me some $$). If you get some time, can you please advise:

1. The section on creating a base map is not directly relevant since Vortech encode such a ('safe') base map? The first step is thus an upload of the base map from the SplitSec to PC?

2. Do you spend much time tuning in CLOSED LOOP mode the better to smoothe the transition between OPEN and CLOSED LOOP mode?

3. The guide seems strongly weighted to tuning 'Map A', the Fuel map, the objective seemingly being to make the resultant (short and long) fuel trims to near zero in CLOSED LOOP mode or close to A/F of 12.0 in OPEN LOOP mode.

4. The only reference to adjusting 'Map B', the timing map seems to be in relation to pulling timing at the lower revs end to avoid spark-knock, the theory being that that part of the map is extrapolated.
4A. Below what RPM does the spark-knock sensor NOT provide information for the 350z (the guide focusses on Toyota)
4B. Is less effort spent in general on timing vs fuel? Or where/how else does Map B come into the tuning equation.

And a 2-part question not covered in the guide:
5A. Should one do an ECU reset before a tuning session or not?
5B. What are the consequences (medium-long term) of doing an ECU reset some time after a tune (e.g. to clear a CEL which occurs). Is the tune wasted? Does the tune map need to be re-downloaded from PC to SplitSec?

Really really appreciate responses in advance.

 

1. The section on creating a base map is not directly relevant since Vortech encode such a ('safe') base map? The first step is thus an upload of the base map from the SplitSec to PC?

Correct

2. Do you spend much time tuning in CLOSED LOOP mode the better to smoothe the transition between OPEN and CLOSED LOOP mode

I always get them mixed up. On the vacuum side of the fuel and timing maps..[ A & B ] are taken care of with the Tune Vortech has already in place . When you get to WOT , Boost , is when you will start to tune the fuel and timing maps ....fuel map would be the only thing to tune if you really want to keep it safe .

3. The guide seems strongly weighted to tuning 'Map A', the Fuel map, the objective seemingly being to make the resultant (short and long) fuel trims to near zero in CLOSED LOOP mode or close to A/F of 12.0 in OPEN LOOP mode.

This has already been taken care of by Vortech [ long and short fuel trims ] unless you go to larger injectors . As far as A/F.....12 to1 ..Most tuners... with F/I cars will keep this lower than 12 to 1 A/F

4. The only reference to adjusting 'Map B', the timing map seems to be in relation to pulling timing at the lower revs end to avoid spark-knock, the theory being that that part of the map is extrapolated.
4A. Below what RPM does the spark-knock sensor NOT provide information for the 350z (the guide focusses on Toyota)
4B. Is less effort spent in general on timing vs fuel? Or where/how else does Map B come into the tuning equation.


Again...the timing for the Vortech kit has been preloaded and is in place...it is a safe timing map . You will spend all of yours and the tuner time , tuning the fuel map .
I wish I had followed my own advice a year ago , when I first started tuning my car . The fuel part is pretty easy to do and understand . The timing is where I screwed up and ended up not retarding timing enough . I ended up breaking a piece of a piston off and it lodged in the valve . Detonation from not retarding the timing enough . So unless you or your tuner is very quallified and feels comfortable changing the timing map...leave it where it is

 

Thanks Booger, thats $$ saved on lots of levels.

Presumably you got no warning signs with your detonation then? Did the piston break at the edge or on the crown? You were sick, sick, sick that day I'm sure.

This article is quite interesting on det. and pre-ignition
http://www.streetrodstuff.com/Articl...tion/index.php

with the following comments from an Automotive Engineer:
Typically APMAX (angle to Pmax) is around 7-10 deg not 14 as he states.

Knock is typically most easily defined in the 12-16kHz region not 6.4kHz as he states (it would pretty much then be a combustion and engine noise measurement device rather than a knock measurement device if it used such a low frequency)