Paxton with little boost???

[Jsparks]

So my tuner just called me and told that she is only putting out about 4.5lbs of boost. Stock pulley, marked the belt with only minimal slippage. ***?

He told me that with the improved exhaust flow(headers, pipes, no cats) that the stock pulley can't keep up.

Any suggestions....I will most likely have to get the smaller pulley

I didn't know that engine performance would effect boost pressure

 

[Jsparks]

O.K. I'm ********!!

Paxton answers my question in the FAQ section on there site....time for a 12lb pulley

Sorry for wasting anytime you have spent on this tread

 

[MikeR]

I dont know what kind of car you have or system, but if its a Paxton on a SRT, you should see 8lbs of boost with the standard 8lb pulley they give you. ILLSMOQ had a problem with stock tensioner from Paxton, slipped alot, he only saw between 4.5 and 6lbs. Put the DLM tensioner on and it was fixed.

So I went with DLM tensioner as well, I get 8+lbs of boost at redline.

 

[mjorgensen Woodhouse]

You definitely will not see the full boost till 6000 rpm. If you are upping the boost with the 12# pulley you will likely need a fuel system change to keep up if you have not already.

Headers and high flow cats reduce back pressure in the motor and will actually lower the boost seen but the power will still be there because the motor is more efficient. If the numbers are still there and the A/F is still safe I would leave it alone.

 

[MikeR]

The Paxton website says 8-9lbs for stock sytem on a SRT, if your not seeing that, you probably have a problem. I have headers and exhaust and am still seeing 8-9lbs.
Maybe you should look into a DLM tensioner.

 

[Fast Too]

The Paxton website says 8-9lbs for stock sytem on a SRT, if your not seeing that, you probably have a problem. I have headers and exhaust and am still seeing 8-9lbs.
Maybe you should look into a DLM tensioner.

They also say without other mods..........I agree that the DLM is the way to go though. When I spoke to Paxton when I purchased my kit they said expect only about 6.5 lbs of boost with the added flow from my Belanger Headers and Corsa Exhaust.

 

[MikeR]

They also say without other mods..........I agree that the DLM is the way to go though. When I spoke to Paxton when I purchased my kit they said expect only about 6.5 lbs of boost with the added flow from my Belanger Headers and Corsa Exhaust.

Thats fine and all, but I have headers, no cats and Corsa, it doesnt flow much better then that. So that would be saying I should be seeing 6lbs. But im not, the Paxton will continue to make boost as long as you can keep the tension on the belt.

 

[Fast Too]

Thats fine and all, but I have headers, no cats and Corsa, it doesnt flow much better then that. So that would be saying I should be seeing 6lbs. But im not, the Paxton will continue to make boost as long as you can keep the tension on the belt.

More boost the better. But you sure your belt isn't over tensioned and are now unknowingly waiting for a bearing or seal failure down the road. ILLSMQU and I have been there and done that with the seal failure thingi. I know he installed yours but rework is no fun my friend......

 

[Jsparks]

I have the DL tensioner and the belt was timed....it's not slipping much. If I swap out to the 12lb I will probably only see 8-9lb of boost which shouldn't need a fuel upgrage. Plus I will make more boost at lower RPM's! Is there a blow-off to relieve pressure under hard stop.....and if so can you regulate the boost at all??

 

[MikeR]

I have the DL tensioner and the belt was timed....it's not slipping much. If I swap out to the 12lb I will probably only see 8-9lb of boost which shouldn't need a fuel upgrage. Plus I will make more boost at lower RPM's! Is there a blow-off to relieve pressure under hard stop.....and if so can you regulate the boost at all??

I still dont understand why you have to change out something just to get what it should get normally. Something has to be wrong......

 

[Jsparks]

You definitely will not see the full boost till 6000 rpm. If you are upping the boost with the 12# pulley you will likely need a fuel system change to keep up if you have not already.

05 SRT

Stock paxton polished kit
DL tensioner
X-metal tb
Billy Boat stepped headers and full exhaust with cat delete

If more fuel was needed would I be able to just change the injectors or I would I need new rails and pumps as well?

 

[Fast Too]

I have the DL tensioner and the belt was timed....it's not slipping much. If I swap out to the 12lb I will probably only see 8-9lb of boost which shouldn't need a fuel upgrage. Plus I will make more boost at lower RPM's! Is there a blow-off to relieve pressure under hard stop.....and if so can you regulate the boost at all??

There is a blow out under your cooler. It is cone shaped and screen meshed.

 

[Jsparks]

I still dont understand why you have to change out something just to get what it should get normally. Something has to be wrong......

I would agree with you...but I talked to Paxton and they say if you improve engine flow you will loose boost..period

Your car seems to prove contrary to that but my car is right in line.

 

[Fast Too]

I still dont understand why you have to change out something just to get what it should get normally. Something has to be wrong......

Mike R - I think he already is, he doesn't have the tensioner we do. I think your belt may be a bit tight though with your sustained Paxton factory boost under your mods. Could be wrong, and hope I am. Watch for oil speckles on your hood pad, and then the all telling quarter size drips of oil on the garage floor. When and if those start run your hand around the blow out. If oil is present on it your seal is shot. Been there. So has your bud ILLSMQU.

 

[Fast Too]

my car is right in line.

They told me the same thing, and I am right there with you, although I have a bit more boost which I contribute to my DLM tensioner.

 

[Fast Too]

05 SRT

Stock paxton polished kit
DL tensioner
X-metal tb
Billy Boat stepped headers and full exhaust with cat delete

If more fuel was needed would I be able to just change the injectors or I would I need new rails and pumps as well?

Just saw you do have the DLM tensioner. I am running ugraded injectors, Seimens 65#. Didn't do nothing with the rails though. I don't have the stock Paxton supplied pumps either nor their SS Box installed. I have an extra in tank Walboro 307 pump and am running the system with a VEC 3.

 

[Jsparks]

he doesn't have the tensioner we do. ILLSMQU.

I do have the DL tensioner... spoke with my tuner and he said around 5.5lbs MAX so I was a little under. Has anyone else ran the 12lb pulley on a stock genIII with exhaust?

 

[Jsparks]

Just saw you do have the DLM tensioner. I am running ugraded injectors, Seimens 65#. Didn't do nothing with the rails though. I don't have the stock Paxton supplied pumps either nor their SS Box installed. I have an extra in tank Walboro 307 pump and am running the system with a VEC 3.

Are running a 12lb pulley?

 

[MikeR]

ILLSMOQ has Kooks headers, No cats and Corsa, also registers 8lbs at 6k rpms, with stock Paxton 8lb pulley. I guess we are the lucky two......

 

[ILLSMOQ]

It is true that with a more efficient exhaust sytem you will see less boost....we are talking a pound maybe two....not 3-4 pounds.

having said that...both my car and MikeR's car both see over 8psi at around 6000 rpm per the spilt second using the r4 program.

 

[plumcrazy]

i agree, exhaust alone aint gonna drop the boost THAT much

 

[ILLSMOQ]

I do have the DL tensioner... spoke with my tuner and he said around 5.5lbs MAX so I was a little under. Has anyone else ran the 12lb pulley on a stock genIII with exhaust?

what is the diameter of the 12 pound pully?

 

[ROCKET62]

How do they time the belt? Can't say that I've heard that discussed before? For those that had belt slippage - what were the tell tale signs?

 

[plumcrazy]

belt slipping usualy = lower boost than usual

 

[RTTTTed]

A can of belt dressing would solve a slightly loose belt, at least for awhile. If the belt was slipping there would be a significant boost increase after spraying the belt dressing onto it. The belt could squeel if it's slipping. Other signs could include damage to the bottom of the belt. May also be dust from wear or the bottom of the belt could be polished from slippage, lots of cracks, missing ribs, etc.

Ted

 

[prevnine11ownr]

Im stock paxton kit also w/ just exhaust.... Mine swings up to 8lbs also !!

 

[PJJP]

Me too. Belangers... I got over 8lbs.

 

[ILLSMOQ]

A can of belt dressing would solve a slightly loose belt, at least for awhile. If the belt was slipping there would be a significant boost increase after spraying the belt dressing onto it. The belt could squeel if it's slipping. Other signs could include damage to the bottom of the belt. May also be dust from wear or the bottom of the belt could be polished from slippage, lots of cracks, missing ribs, etc.

Ted

....are you serious?

 

[ROCKET62]

....are you serious?

While not a permanent solution - it might at least give him some indication if it is the belt slipping as many here seem to think.

 

[Jsparks]

Well basis on the recommendations here I will not put the pulley on. I'm going to see if can't get this figured out with the stock pulley. We crank it down tight for one run and see if that helps.