Rebuilt SN89 low boost

[Winchester73]

What size engine is that on?
My gauge is connected to the vacuum tree on the firewall. I have an auto meter boost gauge that does not "0" when I shut down the car. I always wondered if it was off a bit. I just had the car dyno tuned for the second time due to a conservative tune because I was having spark blow out and cooling issues during the first. It was only off about 1#.
I'm running a cooler as well and the head unit is very hot to the touch. Though my intake temps weren't bad. It was a 92 degree day & it never went over 180. I'm toying with getting a larger cooler. What fluid do you use? I use B&M trickshift

[gikort]

What size engine is that on?
My gauge is connected to the vacuum tree on the firewall. I have an auto meter boost gauge that does not "0" when I shut down the car. I always wondered if it was off a bit. I just had the car dyno tuned for the second time due to a conservative tune because I was having spark blow out and cooling issues during the first. It was only off about 1#.
I'm running a cooler as well and the head unit is very hot to the touch. Though my intake temps weren't bad. It was a 92 degree day & it never went over 180. I'm toying with getting a larger cooler. What fluid do you use? I use B&M trickshift

It is a 306 SBF. My current sunpro gauge sits at -1 with the engine off too. I bought a VDO boost-only gauge that should be here today. I currently have type F ATF in the unit as recommended by Craig Conley and Cundn Racing. I have had both synthetic and non-synthetic B&M in it previously, and will probably replace the ATF with the B&M synthetic again here shortly. I really need to get the intake into the fender. Right now it's right above the headers, which I'm sure is not helping with my intake temps.

[Winchester73]

How does the synthetic B&M work? Have you seen in apart after using synthetic? Does it run cooler? Originally I figured synthetic was the way to go.
But I have always read on this forum not to use synthetic but there was a guy on here that swore by it and even said Craig at PW recommended it. There's some contradicting information here when you start reading the older posts.
I'm running a 4" power pipe but I have no idea if it helped since it was always on their. To me the stock air box works better then most of the CAI kits sold. I don't like the filter just sitting in the engine bay uncovered. Imo its grabbing all that hot air. But then again, I see them all the time on other cars.

[zray]

1). Go back to the synthetic B&M Trick Shift. None better .

2) oBoost gauge probe should be right at the blower case exit where the boost reference line is going to the fuel pump. You will T off of the same line.

3) you must have a cam with a wide lobe separation angle (LSA). A very good cam with the vintage ball drive Paxton, is the old 289 HiPo K code cam. Compcam sells a good replica of them. The so called power cams all have narrow LSA's and will contribute to the low boost numbers you are seeing

Z

[gikort]

Interestingly, without changing anything else, I replaced the type F with synthetic B&M this weekend and lost 1.5 PSI. I was getting 6PSI with the type F, and only 4.5PSI with the synthetic B&M.

[Michael]

B&M Trick Shift is not synthetic. In fact you don't want to run synthetic in a ball-drive blower. The drive mechanism relies on some friction being present - eliminating it can have a negative effect on the amount of boost the blower can produce.

Stick with either regular Type F fluid or original B&M Trick Shirt. Do not use a synthetic fluid.

[vinces427bb]

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[vinces427bb]

did you try T'ing the stingy gage and the better reading gage to see if they show the same amounts of boost from the same source??
2different brands of gages will have different calibration tolerances +/-% [1%, 2%, 5%, & even 10%]
any progress on this issue??

[gikort]

I haven't done much with this car in the last little while as I have been building another N/A Mustang, but the VDO gauge in the hat (obviously) read higher than the gauge in the intake, but It still doesn't feel like it's giving me all it should (I'm not convinced it's any faster than when it was N/A). I'm still getting a lot of belt slippage even with my larger pulleys. I'm thinking the ball tension is setup too tight eating up too much hp to turn and causing a lot of belt slippage. I'm going to pull it apart and set it up at a lower rotational torque and see if that helps reduce belt slippage and free up some horsepower and boost.