Quick upper pulley question...

[BoosT_AddicT]

Hey guys, I had a couple questions. I currently have a 4# lower and stock upper with idlers on my 03. I'm getting a ported blower with 2.5" upper. How much boost will I be pushing and what size belt will I need? Lastly will I need Walbros and Injectors to run that much boost even with a conservative tune? Thanks! :beer:

Yes I did search. I didn't find anything on a 2.5".

 

[Derek@Amazon]

only way to do a 2.5 is to have the snount machined. other wise a 2.75 is about all your gunna get

 

[Scarpino]

only way to do a 2.5 is to have the snount machined. other wise a 2.75 is about all your gunna get

+1

I have a 2.75 upper and a 4# lower = 67.5 belt

May have to break your tab.

I am also seeing 14#'s with this combo

You will not need Walbros and Injectors with this set-up.

You should have the silencer holes filled while thier porting it....that'll be one hell of a scream!

 

[ViciousJay]

i wouldnt touch an upper on a Lightning if you paid me too... its not a cobra, use a lower , swap out the rind and make your life easier

 

[Derek@Amazon]

i wouldnt touch an upper on a Lightning if you paid me too... its not a cobra, use a lower , swap out the rind and make your life easier

no difference in changing a upper on a cobra then it is on a lightning

 

[ViciousJay]

no difference in changing a upper on a cobra then it is on a lightning

why would you change something that only gains liek 1 psi when you throw a lower on and gain 6x the boost, plus you can get slip form going with a smaller upper

 

[Derek@Amazon]

why would you change something that only gains liek 1 psi when you throw a lower on and gain 6x the boost, plus you can get slip form going with a smaller upper

2.75= 2lbs about... cuz i can go just as fast or faster then most 4lb trucks and look 100% stock... get a good belt on the truck and it wont slip much. my fastest pass had a stock belt on it too

 

[RedFox]

I currently have a 2.7 but will be changing to a non-slip 2.6 from South Florida pulley headquarters. They make a good quality pulley.

 

[BoosT_AddicT]

only way to do a 2.5 is to have the snount machined. other wise a 2.75 is about all your gunna get

Well the blower I'm getting is a Stieg port and was machined to accept a 2.5"... I just wanted to know how much more boost to expect. I'm thinking it will be about another 4#'s so I'd have a total of 16#'s... Does that sound right to you guys?

Thanks for the replies!

Oh and do you all think a 67" belt will work with this setup and my idlers?

 

[Derek@Amazon]

not to much is known about the 2.5's because you have to turn the snout down. if i had to guess id say it will be about another 4lbs. but at that point you really need to look into an idler set up like the magnum power bracket.

me persoanly id do the pumps injectors and MAF just to be safe at that point.

its better to have to much of a fuel system then not enough

 

[LightningClint]

^^^ What he said

 

[BoosT_AddicT]

Ok... I'll go ahead and look into the MP idler along with injectors, maf and fuel pumps... Thanks again guys.

If you have anyother input please let me know. Including belt size. Thanks!

 

[Kryo-Genik]

i wouldnt touch an upper on a Lightning if you paid me too... its not a cobra, use a lower , swap out the rind and make your life easier

Ill be doing an upper here very soon.
There is nothing to fear from it..and with the MP bracket belt slip is a non issue.
And with the 2.7 im tossing on there ill be seeing a little mroe than 1# ;-)

 

[ViciousJay]

Ill be doing an upper here very soon.
There is nothing to fear from it..and with the MP bracket belt slip is a non issue.
And with the 2.7 im tossing on there ill be seeing a little mroe than 1# ;-)

Your MP doesnt even put down the numbers my home port does, change all the pulleys you want but i own you :dancenana:

 

[demonatv]

my advice would be to call the guy you are getting the blower from ( JJ ) and ask him what you might need to get to make everything work together

 

[throttle jockey]

A 4# lower with a 2.5" upper will create a 3.40 pulley ratio. If a 8# lower measures 9.5" in diameter, when used with a stock upper a 3.24 pulley ratio results. The pulley combination you're considering is much more aggressive than an 8# lower produces. Most people would agree that the 8# lower/OEM upper is too much for a stock block to handle so I would guess the 8# lower/2.5" upper would be risky on the stock block.

 

[BoosT_AddicT]

my advice would be to call the guy you are getting the blower from ( JJ ) and ask him what you might need to get to make everything work together

JJ told me that with a stock block I will be around 16#'s and he mentioned I will be fine with a safe tune on my stock fuel setup. I trust that.

Worst case scenario is that I am too lean when I get it tuned so I'll just upgrade my fuel system then... Either way I'm pretty excited to see my results. op:

 

[Kryo-Genik]

Your MP doesnt even put down the numbers my home port does, change all the pulleys you want but i own you :dancenana:

Im not tuned for the MP yet either

 

[RedFox]

JJ told me that with a stock block I will be around 16#'s and he mentioned I will be fine with a safe tune on my stock fuel setup. I trust that.

Worst case scenario is that I am too lean when I get it tuned so I'll just upgrade my fuel system then... Either way I'm pretty excited to see my results. op:

I have an Excel spreasheet that lets you play with all the ratios. If you PM me your address, I'll send it to you.

Who makes a 2.5. I've never seen one for the M112.

 

[Scarpino]

Your truck....I say do as you wish. I have had 0 issues with belt slippage. I also know that my truck is not a all out drag truck nor will it ever be. I enjoy the power I have and hope to find some new power soon, but I'm also not trying to set any world records either. All in all, I see the same results with my combo as someone with just a 6# lower but with a little bling under the hood. Good luck with what ever you and hope you get what your looking for.

keep us updated.