Boost pulley combo question

[fepony]

Mine pushes just over 10 with a 6#r.

[Ryan@RhynoTune]

That looks like kilos to me?

[MRBLUEOVAL]

Throw an 8lber with a real coldair setup (JLP Ramair), TR6's and a good dyno tune and you'll see more then double that boost easily! Add an Efan and FTVB and you will not be disappointed in the least!

[BlairTruck]

thats was Kilometers not miles

[cayman150]

Well guys, I've been trying to track down these 'agressive' numbers in the pulleys and boost formulas.

I see various people in the past both here in the NHTOC and in NLOC have posted it before.

Seems like different vendors use different size diameters for their lower pulleys and maybe the stock HD 3.25" upper isn't really 3.25" but more like 3.16"?

Here is a good read and might help out some.....got my head spinning now though....

http://www.nhtoc.com/vbforum/showthr...<br /> <br />http://www.nhtoc.com/vbforum/showthread.php?s=&threadid=2852&highlight=pulley+s izes

[Dbl G]

So if I do this, it will give me this.

1.84 pres.
8.5 LP
2.93 UP
2.7 ED
14.7 PSI
__________
14.36 Boost

[Dbl G]

So now I am at .
1.84 Pres.
8.5 LP
3.25 UP
2.7 ED
14.7 PSI
_________
11.5 Boost

Or

1.84 Pres.
8.5 LP
3.16 UP
2.7 ED
14.7 PSI
__________
12.25 Boost

Depending on the true upper pulley size of the HD upper?
I am slapping 12 on the boost now and I haven't nailed it yet?? 4# lower and a tune?

[Dbl G]

ttt

[cayman150]

Dbl G,

So the numbers say....but the truth is in the kills!

I haven't had time yet to bolt on all my mod's yet so I can't talk from any experience yet. I kinda want to take some base line readings while still stock, add certain parts and then take some readings and then add something else, etc. This way I'll learn what just works and what works really well.

I think my plan will be to install my CAI, TB, T-Stat, & Upper Plenum, taking some readings in between or maybe not depending on time. Then I can play around with some of my pulley combos after I get my wide-band A/F meter. I have 4# lower and 8# lower and 1.80 upper and 1.93 upper pulleys to play with.

I don't want to blow anything up this early so I will take it easy first. It's so hot and humid down here I probably won't make anything like the numbers I see posted here at times.

Hey. it'll be fun getting there though!

[HD pull'n a GT]

I see 15# with a 6# lower and a 2.93 upper. This is with Long tubes. You may see a pound or two more with stock exhaust.

[Dbl G]

Cayman, I hit the Dyno Friday afternoon with the new tune, next week is the next round of goodies.... I will post up chart's

[MRBLUEOVAL]

What your looking at is a 6lber is 12-13lbs boost and an 8lber is 14-15lbs boost. This will vary with CAI, Power pipes and plenum porting or the C&L upper. Once you go LT's you'll lose boost but gain in efficiency. I would stay away from the smaller upper pulley setup. Get an idler for that extra slip protection on a stock upper and swap out lower's until you get what your looking for. Why waste time and money swap both upper and lower to achieve similar results. The slip factor will rise as well.

The only really gains in boost your going to see is through the pulley swaps. I see 1.5-2 with a ported blower/plenum combo but no other mod will change boost any more then a 1/2lb.

I would take a good solid day and do all your mods. Make an appointment before hand with a tuner and then once the mods are on go to the tuner the following day. If you have a Predator you will be fine flashing the pulley tune on and taking it easy if you can't get to the dyno right away. Just don't whale on the boost until you know your tune is correct.

If you want to know what your going to see HP or boost wise on any certain combo post it and I am sure one of us can confirm the numbers to a pretty exact number (within 1lb boost and 10 ponies)

[Dbl G]

I am hitting 12lbs. on the boost now. 4# lower, K&N drop in and a tune.

[Big Jay 02DSG]

Originally posted by HD pull'n a GT
I see 15# with a 6# lower and a 2.93 upper. This is with Long tubes. You may see a pound or two more with stock exhaust.

Thats what im looking to run for boost. who did your tune and what other mods are you running?

[Dbl G]

Depending on altitude and temperature/Humidity. That is good for that combo, close but good.