getrdunn

iTrader: (7)

Hello,
I will soon be ready to cut the holes in my transom for the exhaust. The current set up is through hub. I plan to use CMI's provided they fit otherwise I will use Gils. I was wondering how much difference there is between the TRS and Bravo tips for the CMI's. How much difference is there between the two as far as the tips go? Angle, etc,??? Another words would it be incorrect to purchase a a set of used CMI tips that were used in a Bravo application? This is for a twin engine application.



Thanksm
John

LAKE EFFECT

With a TRS drive the exhaust is 12" farther away from the transom then in a Bravo boat. I dont know if CMI makes a different tailpipe for the TRS, but I know IMCO made a riser that was 3" and 6" higher then the std Bravo setup.

Your dealing with a one off thing. Basic things to keep in mind are that the holes in the transom are above the water line and that the tailpipes and water hoses keep flowing down from the manifold to the transom. And because your engines are 1' farther away from the transom then a Bravo boat, a Bravo taipipe/riser is going to force you to put the hole in the transom lower. If that hole is above the water line, I dont think you will have a problem. Good luck.

LE

getrdunn

iTrader: (7)

Thanks,
So I would assume the angle is different on the TRS and Bravo risers. TRS risers having less of an angle to keep the risers up higher at the transom??? Is this correct?

LAKE EFFECT

I wouldnt say less angle, but a taller riser. Two examples: I had a Formula 311 w/TRS's and Formula used the std Merc exhaust but used a 3" Merc spacer between the manifold and riser. and as mentioned IMCO has a riser that is 3" or 6" higher then the std riser. IMCO's std riser will mimic the same height and angle as a Merc exhaust and riser w/o a spacer.

I believe a couple other aftermarket companies may offer a spacer with there exhausts as well. Just keep the risers as high as your engine compartment will allow, which will help with a possible reversion problem and keep the thru hull's up high as well. Dont be afraid to use 4" exhaust hose to compensate for slight misalignment issues as long as you keep a downward angle to the transom.

Hope this helps.

LE

getrdunn

iTrader: (7)

Thanks,
With That said - what is the desired / mercruiser location for the exhaust holes in a TRS application. I would like to be as close as possible givin that I may change from CMI's to Gils down the road. I have no problem cutting the holes, just want to have them in a so called correct place. LOL...

Just wondering what website would help me out in regards to hole placement. (stock) The way my CMI's are I am a reluctant to go by them. I would rather rig my way to get through the transom so to speak than be dissapionted later if I change the exhaust out. Unless I were to install the engines with the gils and gil risers and take proper measurements and then cut however I would rather mount the CMI's on the engines outside of the boat.

Thanks again for your help.

AIR TIME

best bet get exhaust 1st then put your header or manifold on then take a pvc pipe 4'' and cut it next to the transom while its lined up on the header make your mark cut out if you do it right your new tails should slide in place. you can't mark it with the sstails unless they stop at the transom and you have a rubber hose and tips. my sm exhaust was threw hull and I did't use pvc 1st time I thought the hole was off a 1/2 but over 3ft long it was 4''. if you don't under stand call me Iwill explain art 617 833 3327

US MUSL

I ordered a set of platinum finish CMI E-tops with polished full length dry pipes thru the transom for my 509/TRS set up in the Cig. CMI will have you take few measurements from the crankshaft centerline at the transom and have them faxed or called in.

The result for my application were standard height E-tops and trs length tailpipes that fit like a glove.

Excellent fit, finish, performance, and sound with a two year warranty. Cost was $6,996 for both motors through Offshore Performance in Ft. Myers, FL.

http://www.offshoreperformance.com/O...20Draft6X8.htm

14 apache

iTrader: (1)

update! Was tying to help and I found this.

getrdunn

iTrader: (7)

Wow time flies.

getrdunn

iTrader: (7)

Come to find out through the etops are about the only exhaust that will work with my narrow centers. In regards to the tails either bravo or trs would work from what I can see. With the merctrans there isn't enough difference for either not to work in my application anyway.