Captain's Call/Thru hull exhaust on Tahoe?

[86 century]

Re: Captain's Call/Thru hull exhaust on Tahoe?

You will get next to no performance gain by going to a through hull set up.
Most of the restriction is in the manifolds.

It will get loud that's for sure but any performance gain would be hard to measure.

 

[BiggerDee]

Re: Captain's Call/Thru hull exhaust on Tahoe?

You will get next to no performance gain by going to a through hull set up.
Most of the restriction is in the manifolds.

It will get loud that's for sure but any performance gain would be hard to measure.

Translation for wife..."Yes, there is a performace and mileage gain, but it's really hard to effectively measure it, so I can't really pin it down to a number. Over time though, the system will pay for itself in savings!"

That "time" may be 475 years, but it still holds true! ;-)

 

[grendelsniper]

Re: Captain's Call/Thru hull exhaust on Tahoe?

Is your smart tabs on right? I thought there weren't suppose to be on 2 different parts? I'm trying to figure out the best way / place to put them on my Q4

that is the way I was told from nautica to do the install they sent me different shock connectors to trim pad there is absolutely no binding.

 

[grendelsniper]

Re: Captain's Call/Thru hull exhaust on Tahoe?

Is it very expensive to just put the through hull exhaust in without the diverters? Did you install it yourself?

yes I did the install. measured right where I thought they should go, to find out the steering shaft was in the way. oops. so remeasured and used the existing hole from the depth finder wires as reference measured three more times double checked that before I used the hog 4 1/8" hole saw. I only wanted to cut two hole and it came out perfectly.

 

[grendelsniper]

Re: Captain's Call/Thru hull exhaust on Tahoe?

You will get next to no performance gain by going to a through hull set up.
Most of the restriction is in the manifolds.

It will get loud that's for sure but any performance gain would be hard to measure.

actually I did get better performance gain, yes the manifolds restrict some but most of the restrction is in the y pipe where the two sides meet up to go out the outdrive then there it is restricted as well. Every so often I would start it then dies, I think it has to do with pushing out all the water, I don't know, but I have not had that since.

 

[grendelsniper]

Re: Captain's Call/Thru hull exhaust on Tahoe?

That is exactly what mine sounds like the mercruiser came has a nice tone.

Has anyone installed a thru-hull exhaust system, especially a switch-enabled one that allows automatic switching from the thru-hull system to the prop system, on a Tahoe? Been drooling over this sound for the last year (different boat, bus same 5.0L V-8 as mine on my Q7i):

http://www.youtube.com/watch?v=WqhCHbCl77Y

http://www.youtube.com/watch?v=oYDkVYO15qM

Love it!

 

[dmoss8928]

Re: Captain's Call/Thru hull exhaust on Tahoe?

Post some pics and a video of yours if you can

 

[grendelsniper]

Re: Captain's Call/Thru hull exhaust on Tahoe?

will do, heading to the lake the fist week of august.

 

[BiggerDee]

Re: Captain's Call/Thru hull exhaust on Tahoe?

I *almost* have my wife convinced. The fact that I love to modify/customize all of my toys, and that there really isn't much that can be done to the engine other than the exhaust, almost has me to the green light stage on the project!

Grendelsniper, I'd love to see a pic of the setup in the engine compartment itself if you get a chance at some point. Thanks in advance!

 

[grendelsniper]

Re: Captain's Call/Thru hull exhaust on Tahoe?

ok here ya go execuse the oxidized carb and intake, that's what happens in a enclosed engine compartment, need to paint. I also can't leave stock stuff alone especailly to make improvements, make it run to it's full potential.
also need to remove the y pipe to transome but engine has to be pulled for that. so not sure if it was 3 or 4" pvc caps to plug holes bring rubber connector to hardware store for fitment. you'll see in pic 3 and partial in 4.

1.

2.

3.

4.

 

[BiggerDee]

Re: Captain's Call/Thru hull exhaust on Tahoe?

Great pics, very informative. Thanks! The Holley carb has piqued my interest as well. Have you been happy with it on the Merc?

 

[grendelsniper]

Re: Captain's Call/Thru hull exhaust on Tahoe?

oh yeah, huge difference,my tks quit working carb issue, it is a little big 750dbl pumper I would reccommend a 600cfm or 650, this is what I already had. plus I added an electric choke, you also need to change the intake manifold to a 4 barrel, ebay vortec intake, mine is a edelbrock performer power range fro idle to 5500. square flange for my style carb.

 

[theBrownskull]

Re: Captain's Call/Thru hull exhaust on Tahoe?

grendelsniper, awesome setup. What gear ratio is your lower unit and what kind of prop and pitch do you have?

 

[grendelsniper]

Re: Captain's Call/Thru hull exhaust on Tahoe?

thanks, 1.62 ratio, prop is a 4 blade offshore 21p but hitting rev limiter at 4800 rpm. need different prop not sure what to go with, 23p 3 or 4 blade?

 

[theBrownskull]

Re: Captain's Call/Thru hull exhaust on Tahoe?

grendelsniper thanks for the info. I was wondering what you ran for a propeller given the setup. I bet it sounds good when your at WOT.

 

[BiggerDee]

Re: Captain's Call/Thru hull exhaust on Tahoe?

A 21p with a smaller diameter might be good. As the pitch goes up, the diameter usually has to go down to achieve best results. Props are a pain. I have a 19p and a 21p (both same diameter) for my Q71 (2011, 220HP TKS V-8). They will both run the boat within 1MPH of each other at WOT, but the 21 runs the boat at about 500RPMs less. "Great", I thought, "Same speed, fewer RPMS, less engine wear and gas comsumption!". But then I find out that you want something that hits the top RPM as listed in the engine manual, at WOT, and then you just throttle back from that for better mileage and response. So technically, my 21p isn't utilizing the engine properly. If it were a smaller diameter, it would spin faster, reach the correct RPM, and make my boat slightly faster. My 19p seems to be the best as far as power and speed. I can jump on plane in a heartbeat with 8 adults in the boat (I do have Smart Tabs, and they make all the difference in the world as far as planing goes), yet easily hit 52-55MPH top speed with my wife and two daughters in the boat. That's only a couple of MPH less top end than my stock aluminum prop, but the planing/towing/launch power is worlds better. I wouldn't mind a few more MPH on the top end, but I already get griped at enough for going over 40. I personally have one speed, one gear...GO, but my wife only likes to cruise around at 32MPH. Every so often, I'll convince her to let me drive NASCAR stock cars 175+ at Talladega, and I guess she thinks that will get my speed cravings out of my system. Hardly!

 

[BiggerDee]

Re: Captain's Call/Thru hull exhaust on Tahoe?

I have a couple of dozen RC boats at home, and I probably have 60 props that I have bought for them to experiment to find the best setup. What gives the best top speed, without making the motor turn too many RPMs and overheat it/kill the batteries/make it implode. Finding the "correct" prop is an almost never-ending struggle on a little boat, or a big one!

 

[theBrownskull]

Re: Captain's Call/Thru hull exhaust on Tahoe?

BiggerDee,

I have been dealing with the prop issue myself. I have done the math and the prop calculator and still am not where I want to be. It is frustrating. Maybe I will try a custom prop. but I don't know if I want to spend the money.

 

[BiggerDee]

Re: Captain's Call/Thru hull exhaust on Tahoe?

Yeah, the prop calculator is a joke. The best thing to do is to just find a marine supplier locally that sells props, and see if they have a loaner program. Many now do this sonce the "Correct prop" question is such a stumper, and so different for each application. Put a deposit on one, try it out, take it back for another if it doesn't work, or buy it if it does. You'll wind up paying full price, as opposed to getting a deal on eBay, but you'll know that it works for your application.

 

[grendelsniper]

Re: Captain's Call/Thru hull exhaust on Tahoe?

I need to bring my wot rpm's down it hits the rev limiter 4900rpm with my 4blade 21p might try 3 blade 23 pitch not sure. it worked great when it was the tks 2 barrel carb but now with the holley carb on it, I swear it gained about 40hp. maybe it is more like 25 but seat of the pants difference.