Everyone with boost guages and Ported Eatons!

[trey193]

I noticed the other day while driving my car home that I came up on a long straight stretch and downshifted to second and ran my car up to about 6000 and noticed that the boost on my Hilton overlay guage initially went up to 15 and then dropped as rpm increased, so i did the same thing in 3rd with the same result boost dropped as rpms increased and dropped pretty rapid, then i did the same thing in 4th and it held boost all the way up top to around and 6 where is seemed to drop just a tad but for the most part it held it solid all the way up to around 6. My question is do others with the ported eatons see this drop in second and third gear?? is it do to the no load factor ?? I am thinking it has to be something to do with load since when loaded hard during a 4th gear pull it holds boost a ton better. Everyone with a ported eaton and either the Hilton overlay or a real boost guage go out and do a second and third gear pull and watch the boost guage and see if it drops right away. Also I run no additional idlers and my pulley combo is TR2.80 and 2lb lower with a 77.4 belt I would think if it were belt slip it would do it in 4th as well. ANy info is much appreciated

 

[TRBO VNM]

I do see a drop as well. it is the inefficiency of the eaton.

 

[trey193]

YEah i know boost drop is inherent with the Eaton but I am wonderin why mine drops faster in 2nd and 3rd gear actually 4th gear will maintain 15lb's and hold strong up to around 5800-6 and then drops just a tad.

 

[sbc.cobra]

I noticed the other day while driving my car home that I came up on a long straight stretch and downshifted to second and ran my car up to about 6000 and noticed that the boost on my Hilton overlay guage initially went up to 15 and then dropped as rpm increased, so i did the same thing in 3rd with the same result boost dropped as rpms increased and dropped pretty rapid, then i did the same thing in 4th and it held boost all the way up top to around and 6 where is seemed to drop just a tad but for the most part it held it solid all the way up to around 6. My question is do others with the ported eatons see this drop in second and third gear?? is it do to the no load factor ?? I am thinking it has to be something to do with load since when loaded hard during a 4th gear pull it holds boost a ton better. Everyone with a ported eaton and either the Hilton overlay or a real boost guage go out and do a second and third gear pull and watch the boost guage and see if it drops right away. Also I run no additional idlers and my pulley combo is TR2.80 and 2lb lower with a 77.4 belt I would think if it were belt slip it would do it in 4th as well. ANy info is much appreciated

i'm running a 2.80 upper, 2 lb lower and 4 idler pulleys...i'm running a 77" Gates belt from Napa...you might want to go w/ a smaller belt. i originally had a 76.5" belt w/ only 1 idler pulley (92mm)...then i added the 3 100mm idler pulleys and had to go w/ a 77" belt.

 

[trey193]

What postion on the bracket is your lower idler in?? That makes a difference as far as belt length goes and mine is in the upper position this requiring a longer belt and my belt is right in the middle of travel on the tensioner.

 

[96BlackSnake]

I noticed the other day while driving my car home that I came up on a long straight stretch and downshifted to second and ran my car up to about 6000 and noticed that the boost on my Hilton overlay guage initially went up to 15 and then dropped as rpm increased, so i did the same thing in 3rd with the same result boost dropped as rpms increased and dropped pretty rapid, then i did the same thing in 4th and it held boost all the way up top to around and 6 where is seemed to drop just a tad but for the most part it held it solid all the way up to around 6. My question is do others with the ported eatons see this drop in second and third gear?? is it do to the no load factor ?? I am thinking it has to be something to do with load since when loaded hard during a 4th gear pull it holds boost a ton better. Everyone with a ported eaton and either the Hilton overlay or a real boost guage go out and do a second and third gear pull and watch the boost guage and see if it drops right away. Also I run no additional idlers and my pulley combo is TR2.80 and 2lb lower with a 77.4 belt I would think if it were belt slip it would do it in 4th as well. ANy info is much appreciated

I'm experiencing the same thing, except I have an unported Eaton (currently)

here's my thread I made about it awhile ago...

http://www.svtperformance.com/forums/showthread.php?t=165487

I also changed the belt, and it had no effect...

 

[mlambert]

The blower is too small to maintain the boost.

 

[sbc.cobra]

What postion on the bracket is your lower idler in?? That makes a difference as far as belt length goes and mine is in the upper position this requiring a longer belt and my belt is right in the middle of travel on the tensioner.

i'm not sure...i need to check that out...all i know is it took 2 of us to get the belt on...i had a 2.93 upper and 4 lb lower on my previous 03 Cobra and had belt slip which i chalk up to the length of the belt.

i'm not taking chances on this one...non-slip upper and 4 idlers w/ a tight belt.

 

[CobraBob]

Hmmm. For what it's worth, I never ever saw my boost drop. And believe me, I would notice things like that.

 

[comp 04]

i believe you have a little belt slip also. mine hold 13.5 all the way up. with no slip

 

[badboy]

Mine pegs the Hilton at 16 psi and stays there. I probably should get a better boost gauge since I have no idea what actual boost I am getting. I am running a 6# lower with a 3.1 upper with ported Eaton.

 

[stangfreak]

my ported eaton acts like a centrifugal blower, which i hate.

even on a 2nd gear roll, floor the car, pins to like 11lbs then gradually builds up as the rpms climb to 14lbs. but it doesnt drop. it just pins it there

 

[RiffRaff04]

mine drops too, by a few lbs.

 

[FireRed04Vert]

Here's the question I have....who has done the porting on all these? Is there a difference in porters? Or even styles? I know Steigemier (sp) has different variations of their port jobs and I would be interested in seeing how they perform against each other. Also, how does theirs perform against the Apten and others. (in relation to this issue) I suspect that the port job has something to do with the way they react under boost.

 

[CobraBob]

Mine was ported by Steigemier thru Apten. It was an early gen port.

 

[Cha]

I am actually having a problem that I feel is boost related. My car will hold steady in 2nd and 3rd, but when I nail 4th it will boost higher than other gears. It will hit about 15.5-16lbs in 2nd&3rd, but when I hit 4th it will go 18lbs or so. In fourth..while the gauge is pegging, the car will flatten out or fall on its face. :cuss: The boost actually goes up. I have a 2.8 upper and 4lb lower.

Any suggestions?

Thanks