Water log OT pipes

« **on:** September 05, 2014, 11:08:54 AM »

I have logs and risers now and it feels like at WOT the engine is being choked down the Po had told me he had lost about 500 rpm when he took the headers off and put the logs so my question is do the log OT pipes work better than the snails

Sent from my SCH-I545 using SoCal Jet Boats mobile app

« **Reply #1 on:** September 05, 2014, 12:16:50 PM »

Quote from: Maker on September 05, 2014, 11:08:54 AM

I have logs and risers now and it feels like at WOT the engine is being choked down the Po had told me he had lost about 500 rpm when he took the headers off and put the logs so my question is do the log OT pipes work better than the snails

Sent from my SCH-I545 using SoCal Jet Boats mobile app

Indeed.

Do you have soft exhaust hose with a blue stripe or wire reinforced red stripe?

I like to use copper pipe. With soft hose as couplers.

Sent from my SCH-I545 using SoCal Jet Boats mobile app

« **Reply #2 on:** September 05, 2014, 12:23:33 PM »

Ok i just looked it's the blue hose and it's 27/8 isn't there a larger snail that will take a 31/2 hose. I can pick up OT pipes for 200 from a friend

Sent from my SCH-I545 using SoCal Jet Boats mobile app

« **Reply #3 on:** September 05, 2014, 01:15:46 PM »

Quote from: 429heads on April 22, 2008, 06:39:34 PM

I run BBC at 28 26 hot better lose than tight , what are yours set at know might give you a place to start, Have you check lift , and spring pressure on seat and open is this in your
flat bottom, with blower. What happened to cam card

Really think that 5/8"is going to make a dent?

How much water do you have going through the risers?

What is your temperature at idle?

Got a picture?

Is that hose rigid? Can you squeeze it?

If it is soft wall that will be your problem. Most guys go cheap on the hose and it bites them in the ass.

Sent from my SCH-I545 using SoCal Jet Boats mobile app

« **Reply #4 on:** September 05, 2014, 01:29:07 PM »

I have no idea how much water is going through the risers it idles at 145-150 the gate valve is a little over 3/4 open

Sent from my SCH-I545 using SoCal Jet Boats mobile app

« **Reply #5 on:** September 05, 2014, 01:36:04 PM »

Quote from: Maker on September 05, 2014, 01:29:07 PM

I have no idea how much water is going through the risers it idles at 145-150 the gate valve is a little over 3/4 open

Sent from my SCH-I545 using SoCal Jet Boats mobile app

What temp balls out?

That looks like soft hose to me. It will not allow proper scavenging. Build a crossover and do it in hard pipe.

I will see if I can scare up a picture. ....

Closed hatch?

Sent from my SCH-I545 using SoCal Jet Boats mobile app

« **Reply #6 on:** September 05, 2014, 01:40:42 PM »

Quote from: GT Jets on September 05, 2014, 12:16:50 PM

Indeed.

Do you have soft exhaust hose with a blue stripe or wire reinforced red stripe?

I like to use copper pipe. With soft hose as couplers.

Sent from my SCH-I545 using SoCal Jet Boats mobile app

does this actually make a difference in performance? little more rpm?

« **Reply #7 on:** September 05, 2014, 03:33:26 PM »

WTFO it's about 120 give or take a little I've been playing with the timing because it seems to have a lot due to how its starting it's a 455 with a tunnel ram with 660s and 10.5:1 compression and is spinning a b about 4800

Sent from my SCH-I545 using SoCal Jet Boats mobile app

« **Reply #8 on:** September 05, 2014, 05:37:14 PM »

Quote from: JARVIS on September 05, 2014, 01:40:42 PM

does this actually make a difference in performance? little more rpm?

From what I have experienced. Yes.

Probably not as dramatic as 500rpm worth, but definitely would/could be substantial. Soft hose removes the exhaust pulse because of expansion and contraction. This is the main reason you always see rigid exhaust on extreme performance engine installs.

Mercruiser used hard pipe and manifolds to the point where the exhaust only touches about 1/2"of "hose".

Quote from: Maker on September 05, 2014, 03:33:26 PM

WTFO it's about 120 give or take a little I've been playing with the timing because it seems to have a lot due to how its starting it's a 455 with a tunnel ram with 660s and 10.5:1 compression and is spinning a b about 4800

Sent from my SCH-I545 using SoCal Jet Boats mobile app

What do you mean problem starting? Too advanced?

Get a spring and weight kit to give yourself about 12 degrees of advance on the mechanical and set it for at or near 36 degrees btdc at anything above 2,500 rpm.

Should run like it's scared.

And wire reinforced hose.

Could be worth at least 100 rpm on the top.

GT

Sent from my SCH-I545 using SoCal Jet Boats mobile app

« **Reply #9 on:** September 05, 2014, 06:21:29 PM »

The timing right now is set at 14 and tops out at 36 around 2400 she has great throttle response I'm just thinking I'm losing a bunch on the top

Sent from my SCH-I545 using SoCal Jet Boats mobile app

« **Reply #10 on:** September 05, 2014, 06:40:02 PM »

Quote from: Maker on September 05, 2014, 06:21:29 PM

The timing right now is set at 14 and tops out at 36 around 2400 she has great throttle response I'm just thinking I'm losing a bunch on the top

Sent from my SCH-I545 using SoCal Jet Boats mobile app

You would probably start stepping backwards ~~wroth~~ with more timing.

Do you have a WOT vacuum reading?

Thinking out loud.

GT

Sent from my SCH-I545 using SoCal Jet Boats mobile app

« **Reply #11 on:** September 05, 2014, 06:41:42 PM »

Quote from: Maker on September 05, 2014, 06:21:29 PM

The timing right now is set at 14 and tops out at 36 around 2400 she has great throttle response I'm just thinking I'm losing a bunch on the top

Sent from my SCH-I545 using SoCal Jet Boats mobile app

And at 4,800, I doubt seriously you are losing much on top. She's done pulling is all.

GT

Sent from my SCH-I545 using SoCal Jet Boats mobile app

« **Reply #12 on:** September 05, 2014, 08:06:33 PM »

I know there is more when I can roll off the throttle and the only change is the sound I have built many street race engines most being sbc but the way this one hits the wall at 4800 doesn't seem right that's why I have the exhaust question because it has that chocked up feeling up top

Sent from my SCH-I545 using SoCal Jet Boats mobile app

« **Reply #13 on:** September 05, 2014, 08:12:07 PM »

Quote from: GT Jets on September 05, 2014, 06:41:42 PM

And at 4,800, I doubt seriously you are losing much on top. She's done pulling is all.

GT

Sent from my SCH-I545 using SoCal Jet Boats mobile app

if I had to guess you want to see zero on the vacuum gage?

Sent from my SCH-I545 using SoCal Jet Boats mobile app

« **Reply #14 on:** September 05, 2014, 08:13:34 PM »

I guess I need to find the cam grind the PO told me it was 4° advanced I've always been told to pick the right cam and stick it in straight up anything else and you picked the wrong cam

Sent from my SCH-I545 using SoCal Jet Boats mobile app

« **Reply #15 on:** September 05, 2014, 08:29:03 PM »

Quote from: rush1 on September 05, 2014, 08:12:07 PM

if I had to guess you want to see zero on the vacuum gage?

Sent from my SCH-I545 using SoCal Jet Boats mobile app

As much as I hate to even say it, "zero" is a myth, but yes, it will actually be very close to zero... Probably .015"h.g. vacuum.

Quote from: Maker on September 05, 2014, 08:13:34 PM

I guess I need to find the cam grind the PO told me it was 4° advanced I've always been told to pick the right cam and stick it in straight up anything else and you picked the wrong cam

Sent from my SCH-I545 using SoCal Jet Boats mobile app

No, I disagree, 4° advanced is preferred, Comp Cams actually grinds them at 4°, so in that case, straight up on the timing set.

Quote from: Maker on September 05, 2014, 08:06:33 PM

I know there is more when I can roll off the throttle and the only change is the sound I have built many street race engines most being sbc but the way this one hits the wall at 4800 doesn't seem right that's why I have the exhaust question because it has that chocked up feeling up top

Sent from my SCH-I545 using SoCal Jet Boats mobile app

Called "hitting the wall", she is done. You cannot compare anything you see on a jet boat engine to that of literally anything else but a dyno.

GT

« **Reply #16 on:** September 05, 2014, 08:30:22 PM »

I have to limit my posts because Jet Fever thinks I talk to much...

GT

« **Reply #17 on:** September 05, 2014, 08:31:57 PM »

Quote from: GT Jets on September 05, 2014, 08:29:03 PM

As much as I hate to even say it, "zero" is a myth, but yes, it will actually be very close to zero... Probably .015"h.g. vacuum.

No, I disagree, 4° advanced is preferred, Comp Cams actually grinds them at 4°, so in that case, straight up on the timing set.

Called "hitting the wall", she is done. You cannot compare anything you see on a jet boat engine to that of literally anything else but a dyno.

GT

I guess a lot of people don't realize that zero still means that you have almost 15 psi of atmospheric pressure at all times.

Sent from my SCH-I545 using SoCal Jet Boats mobile app

« **Reply #18 on:** September 05, 2014, 08:40:01 PM »

Quote from: rush1 on September 05, 2014, 08:31:57 PM

I guess a lot of people don't realize that zero still means that you have almost 15 psi of atmospheric pressure at all times.

Sent from my SCH-I545 using SoCal Jet Boats mobile app

My Man!

That is awesome.

« **Reply #19 on:** September 05, 2014, 10:00:43 PM »

Would Thru Transom headers be a big improvement over snails?

« **Reply #20 on:** September 05, 2014, 10:03:54 PM »

Quote from: Handi-Crack on September 05, 2014, 10:00:43 PM

Would Thru Transom headers be a big improvement over snails?

Nearly as good as over transom headers... This deal looks like a closed motor dealio, so I would say jacketed headers, which cost more than many of our boats...

GT

« **Reply #21 on:** September 05, 2014, 10:15:58 PM »

Quote from: GT Jets on September 05, 2014, 08:30:22 PM

I have to limit my posts because Jet Fever thinks I talk to much...

GT

FACT. put a Gate on that.

« **Reply #22 on:** September 05, 2014, 10:21:43 PM »

Quote from: GT Jets on September 05, 2014, 08:40:01 PM

My Man!

That is awesome.

WORD!

***Referring to the 15psi at all times...

« **Reply #23 on:** September 06, 2014, 06:33:07 AM »

Quote from: GT Jets on September 05, 2014, 01:36:04 PM

What temp balls out?

That looks like soft hose to me. It will not allow proper scavenging. Build a crossover and do it in hard pipe.

I will see if I can scare up a picture. ....

Closed hatch?

right now the engine cover is off but it's easy enough to put back on

Sent from my SCH-I545 using SoCal Jet Boats mobile app

Maker

GT Jets

Maker

GT Jets

Maker

GT Jets

JARVIS

Maker

GT Jets

Maker

GT Jets

GT Jets

Maker

rush1

Maker

GT Jets

GT Jets

rush1

GT Jets

Handi-Crack

GT Jets

jet fever

JARVIS

Maker