Only 12lbs of boost with a 2.80? Help please.

[NVMYPWR]

Okay I'll keep this quick and simple.

2.80 Pulley
Stock plugs (haven't put the NGK's in yet)
Stock belt (wrong gatorback sent, waiting on bigger one)
Took idler off until correct belt gets here
Superchips chip is in.

Looking at the stock boost gauge ( I know, I know...will buy some real gauges for the apillar in the spring) it only goes a smidgen past 10...it looks like it would be about 12lbs of boost.

What could be the cause of this?
Belt slip?
Stock plugs?
Stock belt?
Gauge is THAT inaccurate?

I would appreciate ANY comments or advice.

Thanks in advance!

 

[SolidSnake]

Belt slip, check for belt dust.

How humid? Weather plays a factor.

 

[NVMYPWR]

70 degrees outside
42% humidity

 

[Snkbyte]

Your idler being off would be my guess. What brand pulley?


Will

 

[Juiced-03]

LOL you can't use the stock belt with a 2.80!!! You need to use a 73.5" belt with no idler! I bet you are losing 2-3 lbs. of boost just by using the wrong belt!

 

[Snkbyte]

And stock belt missed that :lol



Will

 

[NVMYPWR]

Originally posted by Juiced-03
LOL you can't use the stock belt with a 2.80!!! You need to use a 73.5" belt with no idler! I bet you are losing 2-3 lbs. of boost just by using the wrong belt!

lol...well that's what I wanted to hear. That makes me feel better.

I have a 73.5 belt but that's the problem. I need a 74 so I can put my idler on.


I took off the idler though and then tried to install the 73.5 gatorback but I don't see how in the hell that belt is supposed to get on there. It seems to short.

The pulley is a SFPHQ pulley

 

[coleman]

2.80 = 74.0"

 

[Jim Vaccaro]

With 2.80 Pulley you can use a 73 1/2 in Belt

 

[Poisonous Mods]

I only see 12.4-12.7psi of boost MAX with my 2.80" Upper & 2 x 100 Idlers.

I should be seeing 14psi but i could be my exhaust. Free Flowing. My Tensioner is right in the middle & im sure i dont have any belt slip at all BTW.

It could also be that i didnt install it right but i see 20vac but some times now it will sit at 18vac after a hard run at the track which is strange. :shrug:

 

[KiLLaBytE]

Originally posted by NVMYPWR
lol...well that's what I wanted to hear. That makes me feel better.

I have a 73.5 belt but that's the problem. I need a 74 so I can put my idler on.


I took off the idler though and then tried to install the 73.5 gatorback but I don't see how in the hell that belt is supposed to get on there. It seems to short.

The pulley is a SFPHQ pulley

did you loosen the tensioner?

 

[NVMYPWR]

Originally posted by KiLLaBytE
did you loosen the tensioner?

edit:

To get the belt on? Of course. It just seems like the 73.5 was still too short. I tried to put it on the 2.8 pulley last and just wasn't able to get it on with the tensioner all the way down.

Any suggestions?

 

[YoungCobra]

I don't beleive my stoc boost gauge reads past 10 psi. Maybe you really are making more boost and your gauge is actually pegged?

If I'm wrong, can someone tell me where 12psi would be?

 

[Andorion]

Originally posted by NVMYPWR
edit:

To get the belt on? Of course. It just seems like the 73.5 was still too short. I tried to put it on the 2.8 pulley last and just wasn't able to get it on with the tensioner all the way down.

Any suggestions?

You should loosen the tensioner, slip the belt OFF the idler (to the right of the snout) and onto the 2.8, then slip it onto the (smooth) idler - should be much easier.

~Berj

 

[Dana]

Two suggestions:
1) put it on the right side idler last, not the blower pulley.

2) cut off the tensioner stop.

Dana

 

[Andorion]

Originally posted by YoungCobra
I don't beleive my stoc boost gauge reads past 10 psi. Maybe you really are making more boost and your gauge is actually pegged?

If I'm wrong, can someone tell me where 12psi would be?

Heh, guess we all missed the word "stock" in his original post =) You're absolutely right, the stock gauge only shows up to 11 (on the right side of the thick 10 line) so he's definitely pegging it!

~Berj

 

[wicked03snake]

my 2.8 maybe sees 13 psi on a good day. i think 10 is at the middle of the big mark and mine goes just a little way past, maybe 1/8 of an inch past all marks on the boost guage. i have 2 100mm idlers, 1 90mm, gatorback 74, belt and diablo chip. i have an off road x pipe and flowmasters welded into the stock catback, but the boost didnt read any higher before i put on any exhaust modifications. it has a lot to do with inlet restrictions too so check that out. i have the upr cai and stock mass air, throttle body. i cant remember if the boost was any higher before i welded in the flowmasters.

 

[NVMYPWR]

Originally posted by wicked03snake
my 2.8 maybe sees 13 psi on a good day. i think 10 is at the middle of the big mark and mine goes just a little way past, maybe 1/8 of an inch past all marks on the boost guage. i have 2 100mm idlers, 1 90mm, gatorback 74, belt and diablo chip. i have an off road x pipe and flowmasters welded into the stock catback, but the boost didnt read any higher before i put on any exhaust modifications. it has a lot to do with inlet restrictions too so check that out. i have the upr cai and stock mass air, throttle body. i cant remember if the boost was any higher before i welded in the flowmasters.

That's about how far mine goes past the stock gauge.

I just assumed (I know...shouldn't do that...lol) that the needle on the stock gauge would keep going past 10 because I saw that a guy on here was selling an overlay marked up to 16 I think. So I figured it would naturally go that high.

Has anyone's gone past 1/8th past the 10?

 

[stang03svtcobra]

wow, this is interesting... i use a 2.93 a 2.80 belt and i see 14.5 if not 15 ibs then drops to about 13 at 6k rpms

what are the benifits of a 2.80 a little off subj but just wondering also i dont use and after market idler???

 

[roushraven]

Has anyone's gone past 1/8th past the 10?

There is a peg underneath the factory boost gauge needle that makes any boost levels higher than about 10 useless without the overlay from Ray Hilton.