Questions about exhaust logs and risers

[72BBO]

I need to replace the Berkeley manifolds on the Carlson. I am leaning towards the Glenwood manifolds at www.DanaMarineProducts.com



The standard risers cost almost as much as the manifolds themselves, but I know that they will help prevent water from entering the engine when anchored or not running.
My question is that the straight risers are considerably cheaper, and I would think that they would also be less restrictive with the straighter flow path. Would flappers on the exhaust tips be enough protection from water getting into my engine? Are there any other disadvantages to running the straight risers? I am a new boater and I'm kinda skeptical about making major changes without knowing the pros and cons.





Thanks, Brian

[Stitch King]

I think the Straight ends have a bit of a downward tilt for Center Engine Inboard Ski boats. If this is a jet with the motor at the back i would not use anything other than the risers. The chance for getting water in the motor is to great otherwise.

Be patient and watch ebay. That's how I was able to get a set for my old 460 jet boat.

[OldSleekOlds]

I think the Straight ends have a bit of a downward tilt for Center Engine Inboard Ski boats. If this is a jet with the motor at the back i would not use anything other than the risers. The chance for getting water in the motor is to great otherwise.

Be patient and watch ebay. That's how I was able to get a set for my old 460 jet boat.

I agree, Glenwood would be my first choice with the big risers (I'm using those with 3 1/2" hose). HOWEVER, if your engine is mounted close to the rear of the boat, make sure you will be able to get the Glenwoods in there. They are at least a couple of inches longer than what you are replacing. I tried to drop a complete engine/exhaust set-up in my boat and found that the Glenwood risers hit the rear of the boat. I ended up with Hardin logs and Glenwood risers.



Lost rpm in the process. This is a pic of the engine on a Dyno, best I have to show the logs.

Roger

[Morgan's 6-C]

I agree, Glenwood would be my first choice with the big risers (I'm using those with 3 1/2" hose). HOWEVER, if your engine is mounted close to the rear of the boat, make sure you will be able to get the Glenwoods in there. They are at least a couple of inches longer than what you are replacing. I tried to drop a complete engine/exhaust set-up in my boat and found that the Glenwood risers hit the rear of the boat. I ended up with Hardin logs and Glenwood risers.



Lost rpm in the process. This is a pic of the engine on a Dyno, best I have to show the logs.

Roger

Don't mean to hijack the thread, but a couple questions if I may:

What kinda numbers did you get from the dyno runs, and what setups did you try?

Reason I'm asking is, that looks like a lot more intake, than I'd normally associate with the typical Olds RPM range, especially with a relatively restrictive exhaust system.

Looks like intake runner volumes that start to come on strong at close to 6000 rpm and hurt torque below 4000.

Or is the Olds very much modded?



Darlene

[SportJ-US-1]

Don't mean to hijack the thread, but a couple questions if I may:

What kinda numbers did you get from the dyno runs, and what setups did you try?

Reason I'm asking is, that looks like a lot more intake, than I'd normally associate with the typical Olds RPM range, especially with a relatively restrictive exhaust system.

Looks like intake runner volumes that start to come on strong at close to 6000 rpm and hurt torque below 4000.

Or is the Olds very much modded?



Darlene

I agree. That is a high RPM intake and a mechanical secondary carb which would hurt where a jet boat needs it most, on the bottom end. There are over the transom wet headers that would work alot better with that intake.

[OldSleekOlds]

Both "Highjackers" are correct. That's a Victor intake. The motor lost about 35-40hp compared to the Performer I started....and finished with. Here's the final sheet using the Performer. All pulls were done with the exhaust seen in the pic. The objective was to see if there is ANY way to get 500hp with the log exhaust on that motor. Not gonna happen...at least not with a NA set-up.



A friend owns the Dyno. We had it on there for 2 weeks. Lotsa changes. The Dyno guy has a 1500+ hp dual turbo motor in his boat. He keeps trying to push me into turbo land. Oh to be young again.

Roger

[Morgan's 6-C]

Both "Highjackers" are correct. That's a Victor intake. The motor lost about 35-40hp compared to the Performer I started....and finished with. Here's the final sheet using the Performer. All pulls were done with the exhaust seen in the pic. The objective was to see if there is ANY way to get 500hp with the log exhaust on that motor. Not gonna happen...at least not with a NA set-up.



A friend owns the Dyno. We had it on there for 2 weeks. Lotsa changes. The Dyno guy has a 1500+ hp dual turbo motor in his boat. He keeps trying to push me into turbo land. Oh to be young again.

Roger

Thank you so much for sharing. Most folks aren't so forthcoming when they try something expensive that doesn't work as hoped.

I'd worry, alot, about the aluminum log manifold with a blower, when on boost in the lower and mid ranges, there's a lot of fire out the exhaust ports. The water jacket cooled stainless headers like the offshore boats use might be a way to gain HP with what you have already, and then you'd be "blower ready".

But you hit the nail on the head though, big HP numbers, for reliable boating applications, come from forced induction.


Darlene

[72BBO]

I would like to thank you guys for your input and experience. I did some measuring on the distance between the stearn and the back of the engine. The distance from the rear most exhaust bolt hole to the stearn is approximately 21". The Glenwood logs are 4-1/2" from the the bolt hole and the standard risers are 13", totalling 17-1/2". This leaves 3-1/2". With the exhaust trumpets extending about 2-1/2" into the transom this leaves me a 1" gap to to be filled in with exhaust hose.

The water jacket cooled stainless headers like the offshore boats use might be a way to gain HP with what you have already, and then you'd be "blower ready".Darlene

I don't think anything like this is available for Olds. The best bet would be the thru transom headers at $1000.00 but they are not to be used under an engine cover.

[OldSleekOlds]

I would like to thank you guys for your input and experience. I did some measuring on the distance between the stearn and the back of the engine. The distance from the rear most exhaust bolt hole to the stearn is approximately 21". The Glenwood logs are 4-1/2" from the the bolt hole and the standard risers are 13", totalling 17-1/2". This leaves 3-1/2". With the exhaust trumpets extending about 2-1/2" into the transom this leaves me a 1" gap to to be filled in with exhaust hose.




I don't think anything like this is available for Olds. The best bet would be the thru transom headers at $1000.00 but they are not to be used under an engine cover.

I'm not clear on the dimensions (too many numbers). The problem I had was that the rear (hump) of the Glenwood risers hit the deck at the rear of the engine compartment and the whole thing needed to go back about 2 more inches to line up the mounts. Another important consideration is alignment. If you look closely at the pic of my motor, you can see a wedge between the riser and the log manifold. This was necessary to get the stuff lined up with the holes in the transom. I have a CAD program, and a machine shop. For me, it was easy. For others.....maybe not so easy. The 1" gap is OK as long as it lines up. The smaller the gap, the more critical the alignment.

A few months ago, Paul Bassett quoted me $3700 for a set of stainless water cooled headers that could be put in a closed engine compartment. This was for my 455 Olds. In a few weeks I'll be 70 (Lord willing), and unfortunately, the money just can't flow as free and easy as it used to. It would be great....but at least for now, I'm gonna have to pass.

[julius750]

I realise this is a late post, but you may be interested in these for 455 Olds, no water reversion, plenty of HP and torque, made to your specifications, Jet, shaft, V-Drive, sterndrive. Not cheap, but 5 year warranty - all stainless steel, lightweight, watercooled headers. available powdercoated finish or mirror polished.

Also available Chev 350 454 502 496 LS1 LS11, Ford 351 Windsor 351 Cleveland (2V or 4V) 460, Chrysler 318 360 383 440, Buick V6 405 445, Lexus 4.0 quad cam, etc etc. O2 sensors, Turbo, high output, Over transom with integrated mufflers and run cool! no more burn't passengers or hot engine bay!

[OldSleekOlds]

I realise this is a late post, but you may be interested in these for 455 Olds, no water reversion, plenty of HP and torque, made to your specifications, Jet, shaft, V-Drive, sterndrive. Not cheap, but 5 year warranty - all stainless steel, lightweight, watercooled headers. available powdercoated finish or mirror polished.

Also available Chev 350 454 502 496 LS1 LS11, Ford 351 Windsor 351 Cleveland (2V or 4V) 460, Chrysler 318 360 383 440, Buick V6 405 445, Lexus 4.0 quad cam, etc etc. O2 sensors, Turbo, high output, Over transom with integrated mufflers and run cool! no more burn't passengers or hot engine bay!

Interesting reply. Who manufactures the product you're referring to? What is the cost? Is there real data to support the claims?

There is great potential here for a new concept. The concept is not really new, it's possible to make a manifold of the style shown, keeping the rise high enough to keep water from coming in and STILL fit under an engine cover. It would be new for an Olds.

OT exhaust systems are cool. Around here it's near impossible to get a boat with OT exhaust insured. Don't bother telling the insurance co. that they are not hot. They don't care. They just have a company policy. If the exhaust doesn't go through the transom, they don't insure it.

There is a large market for an efficient (better than logs) exhaust system for an Olds that will fit under an engine cover. Logs and risers fit under a cover. It's not rocket science.

The trick will be to come up with something that folks can afford to buy.

Speak to us!!

[julius750]

We make them in Australia, prices for through transom (or through prop exhaust for sterndrive) small block start around USD$2,000.00 pair, Big block from under USD$3,000.00 pair. We are aware of some stainless tube in tube watercooled headers made in U.S. which look great but do not last. performance and durability is confirmed by testimonials from satisfied customers. Performance improvements comparable to CMI units which are made for only a limited range of applications whereas we make them for whatever the customer wants (within reason).

[OldSleekOlds]

We make them in Australia, prices for through transom (or through prop exhaust for sterndrive) small block start around USD$2,000.00 pair, Big block from under USD$3,000.00 pair. We are aware of some stainless tube in tube watercooled headers made in U.S. which look great but do not last. performance and durability is confirmed by testimonials from satisfied customers. Performance improvements comparable to CMI units which are made for only a limited range of applications whereas we make them for whatever the customer wants (within reason).

Bassett offers stainless tube in tube through transom headers for Ford or Chev for $2700. For Olds he wants $3700. I have never heard any complaint regarding quality. Bassett has a reputation for a quality product. There are anecdotal references indicating significant hp increases over log exhaust systems.

Considering your location and lack of local service, I suspect you may have difficulty selling your product in the US. If somebody has a problem, Australia is very far away.

[The Big Al]

The straight headers without risers will be a major problem when you set the boat down from a run. the back wash pressure is what the risers protect you from the most.

Glenn wood is a great product and will find they make them for other company's.

Also, Bassett quality is outstanding! THEY ARE NUMBER 1 (JMO)

[julius750]

We do send product to U.S. packing and express delivery USD$195.00 to most locations. We give a 5 year warranty regardless of use - recreational or race, compare that to local product. It is a boutique product developed for durability as well as performance improvement.