Boost leak on Paxton?

[92fiveohfox]

If I had a boost leak on my Paxton, the maf/lb number should be really low, correct? It is only showing 5.6lbs on my gauge. 3.8 pulley and jlt. It maxes maf/lb on logs, I assume it wouldn't do that if it was only getting 5.6lbs. I may have the gauge hooked up wrong, it's on the same line as the bov, with a y adapter. Most people tap into the brake booster line it seems.

What would a boost leak look like on a log?

 

[Mr. Mach-ete]

So how does the car run?

 

[Deerslayer]

I tee'ed my gauge into the brake booster vacuum line for my boost gauge and also my BOV vacuum is tied in there as well. I have a wastegate but boost at WOT pulls builds to 10psi pretty quick on my digital gauge. Your gauge reads 5.6 at WOT?

 

[92fiveohfox]

I tee'ed my gauge into the brake booster vacuum line for my boost gauge and also my BOV vacuum is tied in there as well. I have a wastegate but boost at WOT pulls builds to 10psi pretty quick on my digital gauge. Your gauge reads 5.6 at WOT?

5.6 @ 7200 wot, at 3500 it's only reading 1 psi. I have an auto, I'm not sure if that makes a difference where to t the vacuum into.

 

[PC03GT]

You should be making almost 10lbs of boost with a 3.8 pulley

 

[92fiveohfox]

You should be making almost 10lbs of boost with a 3.8 pulley

Right... that's why I'm wondering if having the gauge on the same vac line as the BOV will cause it to not be accurate or if I have a boost leak. I tried another gauge and it read the same. Guess I'll have to tap into another vac line to test and see, I was curious what other people were using.

 

[Krace]

I'm betting belt slip... Mine did the same thing when I first installed it.

 

[92fiveohfox]

I'm betting belt slip... Mine did the same thing when I first installed it.

Highly doubtful from the logs, how did you figure it out/fix it? The belt cant get any tighter than it is. I'm running a 102" belt on the 3.8 pulley(stock is a 103.5 I think), it BARELY goes on there.

 

[Krace]

When does it hit 5psi, only at 7k? Or does it hit 5psi at 5k and stops climbing?

 

[92fiveohfox]

When does it hit 5psi, only at 7k? Or does it hit 5psi at 5k and stops climbing?

Climbs all the way, 5k is 3-4 I think

 

[beefcake]

double check all the clamps and fittings, might have a pipe not tightnened all the way

 

[TTUhouston]

Did you ever find this out? I just went to the track and ran a 117 mph trap speed; thinking this is my problem. Bringing up a pretty old thread I know...

Double checking all the clamps and fittings is not quite as easy as it sounds!!

 

[92fiveohfox]

It was a bad gauge. When did you run? Did you log it? What's the timing and rest of the setup?

 

[TTUhouston]

bone stock motor, exhaust, everything. 12.1@117, 12.2@116, 12.2@116, logs of all 3. Timing I will look first thing in the morning, but I think it was around 14 deg (Lund tune with my beefcake setup). We were having knock issues over 14 deg and couldnt find any false knock so kept the timing conservative. It was 1500-1700 DA that night due to humidity and heat.

 

[TTUhouston]

11 degrees timing at 5000 RPM up to 13.5 degrees timing at 7200 RPM, keeps hitting 7400 RPM for some reason but set shift at 7000 RPM I thought.

 

[92fiveohfox]

Stock 6r80? What's your 60'? That timing is super low and the da isn't great, could be your issue. I'm in Houston too, be glad to take a look at it if u want.

 

[TTUhouston]

Stock auto. 60's were 2.00 to 2.03. The timing may be the issue I agree. Ordered a boost gauge to confirm I have proper boost; will install tonight or tomorrow.

I was seeing knock at 14-15 degrees timing so we pulled it back. 93 octane in town was giving me troubles.

 

[92fiveohfox]

2.0 60 is no bueno. I'm guessing it's not spinning just bogging? Get a torco tune or switch to e85 and you will pick up over 100hp.

 

[92fiveohfox]

Also get an off-road x or h at least.

 

[TTUhouston]

Been considering the E85... wanted to keep it as close to stock as possible but still beat my buddy's M3 with supercharger. Hes running 123-124 traps and my 117s arent cutting it. I beat him every time because I actually am launching better.

My launches dont bog or spin that I can tell. It is funny. I stall up to ~2.5kRPM and hold brakes. Any more and the front breaks loose. I tried a lot of different things so far to get that 60' down. I am running 285 555R drag radials. Should be getting better than 2.0 60s.