|
Thanks Ray. You may remember, you and I visisted early on in my project about your individual runner system. That's what drove me towards using a small plenum design. Unfortunately using an existing manifold and hatch clearance limitations, I wasn't able to optimize runner length and plenum volume, but it seems to work pretty well.
As far as cost I've not given it a lot of thought. It would be a great upgrade to a 500/525 based engine. The cost of the throttle bodies would be the key. Dave Gilbreath machined them so he'd have to come up with a cost figure. I know it couldn't be done very cheaply. I'm guessing we spent close to $800 on material alone.
Originally Posted by Raylar
(Post 3473844)
Hey Bob, nice work and a great result.
As we all seem to say now, when it comes to naturally aspirated in a marine engine,"THERE AIN'T NO REPLACEMENT FOR DISPLACEMENT!" We did a lot of development on the 598-600 cubic inch versions of the 8.1L 496 Gen 7 engine as you know and we developed two different intakes that would support 750HP on the big cubes and higher flowing CNC'd heads. One was a redo of our existing 496 manifold that was reasonably priced using two 1200 cfm throttle bodies. The long runners and big plenum developed huge torque like you are seeing in your great creation and the other is our stack in line fuel injection system we built for the HO750 engine. The later obviously has the wow factor but the cost of this type keeps most guys wallets in their pockets! I am curious what you think your beautiful system would sell for? You also qualify as an "Official Rocket Scientist" for that amazing throttle linkage set-up- NICE WORK! The design and CNC work on the throttle bodies is really nice and obviously the system works very well as the dyno sheets show. Congratulations on some nice development work! Best Regards, Ray @ Raylar |
Awsome engine Bob and that one of a kind intake design and four throttle body linkage is a thing of beauty. Great job! Sorry I did not see this post until now.
Bill |
Question
Originally Posted by bobl
(Post 3472889)
Here are a couple of pics of the engine. The low end torque is truely amazing, and I don't have to spin a ton of RPM. I'm sure a huge intake and dominator style carb/tb would make more peak HP, but you can't beat the cool factor and torque.
Bobl, I was wondering what type of air filtration is used on that injection system? Impressive! |
Extremely nice.
Uncle Dave |
Originally Posted by Raylar
(Post 3473844)
Hey Bob, nice work and a great result.
As we all seem to say now, when it comes to naturally aspirated in a marine engine,"THERE AIN'T NO REPLACEMENT FOR DISPLACEMENT!" We did a lot of development on the 598-600 cubic inch versions of the 8.1L 496 Gen 7 engine as you know and we developed two different intakes that would support 750HP on the big cubes and higher flowing CNC'd heads. One was a redo of our existing 496 manifold that was reasonably priced using two 1200 cfm throttle bodies. The long runners and big plenum developed huge torque like you are seeing in your great creation and the other is our stack in line fuel injection system we built for the HO750 engine. The later obviously has the wow factor but the cost of this type keeps most guys wallets in their pockets! I am curious what you think your beautiful system would sell for? You also qualify as an "Official Rocket Scientist" for that amazing throttle linkage set-up- NICE WORK! The design and CNC work on the throttle bodies is really nice and obviously the system works very well as the dyno sheets show. Congratulations on some nice development work! Best Regards, Ray @ Raylar Were the tubular runners better than using a dual quad intake? |
Right now I have just some wire mesh flame arrestor matterial in the throttle bodies. I have clearance issues in the boat. I designed the throttle bodies to bolt oval flame arrestors on them if desired. This winter I plan on building a ram air/flame arrestor system into the hatch.
Bob
Originally Posted by TEXASRPM
(Post 3483649)
Man after looking at that I don't even feel like a novice:eek:
Bobl, I was wondering what type of air filtration is used on that injection system? Impressive! |
Question?
Originally Posted by bobl
(Post 3472889)
Here are a couple of pics of the engine. The low end torque is truely amazing, and I don't have to spin a ton of RPM. I'm sure a huge intake and dominator style carb/tb would make more peak HP, but you can't beat the cool factor and torque.
Bobl, I am just impressed, did you fabricate that linkage setup? Also, am I correct to say that I am looking at a custom plenum sitting on top of a square bore type intake manifold? Do each of the TBs feed a particular bank of cylinders ? Thanks |
Originally Posted by bobl
(Post 3484043)
Right now I have just some wire mesh flame arrestor matterial in the throttle bodies. I have clearance issues in the boat. I designed the throttle bodies to bolt oval flame arrestors on them if desired. This winter I plan on building a ram air/flame arrestor system into the hatch.
Bob |
Question - I notice on the dyno charts that one pull starts at 34 the other 3500.
Typically one starts where they can stabilize the load and your mill is just a hair higher than the usual 3000 rpm. How does the mill idle? Uncle Dave |
The dyno was set at 3500 to start the pull. If I hit the record button a little early, it starts recording there. I did some pulls down lower but was having a tough time holding it steady with the larger water orfices I had installed on the dyno. I always hold the load for a few seconds to stabilize before recording, but the rpm will still fluctuate slightly. A bigger dyno water supply would help that($$$). With lower HP I reduce the outlet orfice size to allow loading it more down low, but it really increases the heat in the dyno if you run up the power without increasing the outlet orfice size. Hope this helps explain.
The cam is ground on 114 lobe separation with 250/258 duration so it's not too radical. It's programmed to idle at 800 in neutral and will lug down to about 675 when put in gear until the iac picks it back up to 800. The exhaust has turn downs that exit right at the water line (84 db). It's very docile. I've got about 35 hrs on it this summer and it's been flawless, once I got it fine tuned. Bob
Originally Posted by Uncle Dave
(Post 3485430)
Question - I notice on the dyno charts that one pull starts at 34 the other 3500.
Typically one starts where they can stabilize the load and your mill is just a hair higher than the usual 3000 rpm. How does the mill idle? Uncle Dave |
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