Many of you probably know I've been building a new engine for my 18' cp gullwing. This boat is not a race boat and I tried hard to resist going to far in that direction. I don't want to be the fastest guy on the river, just wanted something that runs "good". I'm not a professional engine builder, just a garage hack, so don't be to critical. It is a 565ci all aluminum chevy with 335 AFR cnc heads, two AED 1050's, 14:1, Straub cam, and a bunch of other stuff.
Well I just dynoed the engine this weekend and I'm posting one of the dyno sheets for your review, along with a couple of pic's of the engine. I'd appreciate your feedback on what you think.
A couple of notes on the dyno sheets: 1. Notice that the vacuum pump didn't maintain vacuum throughout the run. My vacuum pump is setup to run off of the driveshaft at the rear of the motor so I wasn't able to use it on the dyno. We used a Star electric standalone pump instead. We wanted 12 to 14" of vacuum, but didn't get it. So, how much do you think that hurt my numbers? 2. The fuel pressure gauge was not hooked up. We used an electric Performance Engineering pump on the dyno, but I plan to use a Clay Smith mechanical pump in the boat.
Very nice motor,good looking as well !! You had 9"vac so maybe a couple hp if that,not going to change that much from 9 to 12".
What was your hot valve adjustment? and what temp did you make ur pulls at?
I was wondering about the depression levels throughout the run. My thoughts were either the pump couldn't keep up or you are getting a little ring flutter as rpm climbs.
Don't really matter though, it runs as good as it looks!!!!! devil
There are very few pics where I cant find a single thing I would change. Every piece is top drawer. You just can't complain about close to 950 HP or 800lbs @ 5000.
Steve,
First of all that thing is nothing but "Eye Candy". PB needs to give you a little press time with this build. Your attention to detail proves you are no "Garage Hack". Very nice piece.
The dyno sheet. All I can see is it has very usable power. To many times you see a sheet with impressive numbers, but they are at an rpm range that the engine will never see. This came up last night in conversation, 1000HP engine but at 8500 rpm and the engine will never see over 7200 in its application. YOu have 940+ HP at 6600 rpm and 800#/ft at 5000 rpm and if you do my math on the torque curve of 7% on either side you carry within 7% of peak to damn near 1500 rpm over peak. The compression has helped greatly with this but she will pull like a freight train.
Maybe when I come to Firebird for the NJBA race I can sneek a ride !!!!!!!!
Steve,
First of all that thing is nothing but "Eye Candy". PB needs to give you a little press time with this build. Your attention to detail proves you are no "Garage Hack". Very nice piece.
The dyno sheet. All I can see is it has very usable power. To many times you see a sheet with impressive numbers, but they are at an rpm range that the engine will never see. This came up last night in conversation, 1000HP engine but at 8500 rpm and the engine will never see over 7200 in its application. YOu have 940+ HP at 6600 rpm and 800#/ft at 5000 rpm and if you do my math on the torque curve of 7% on either side you carry within 7% of peak to damn near 1500 rpm over peak. The compression has helped greatly with this but she will pull like a freight train.
Maybe when I come to Firebird for the NJBA race I can sneek a ride !!!!!!!!
Wow...that thing is impressive. Good job. Only thing I might do would be to take the fuel regulator off the hard mount.
Not a race engine? LOL...yeah, right. If you say so.
NICE looking engine. What's that thing weigh, ready to run?
Looks like it will still make some good power after 7000rpm too. Given that it peaked at 6700, and only fell off 5hp in the next 300rpm, I'd bet it will still be making over 900hp at 7400-7500. I assume it's a solid roller? How hard do you plan to turn it in the boat?
Wow, you guys really overwhelm me with your kind comments. Thank you! Many of you have helped me with this project either directly by providing me with parts (Chris Straub), with your assistance & guidence (gn7, cs19, fuelinmyveins & steelcomp), or indirectly via reading your comments to others here on the forum (Warp Speed, and many others). Believe me, I could not have done this without all of your help. Again, thanks!
that wasnt what i expected to see at first. that is very cool! and you gotta love the numbers. you didnt cut any corners there even if it ever breaks, just park it and your still a winner! you will get 1st place at the show and shine. nice work, belongs in a glass case.
Steve, like I said in the Pm's great job on every aspect. That cp will haul some serious ass.
Is the lower belt drive pulley seated all the way? The belt hangs off a bit on the upper belt drive pulley, the bottom pulley guides the belt.. You sometimes have to wail on the thing a little bit to get it seated all the way. Just making sure.
Is the lower belt drive pulley seated all the way? The belt hangs off a bit on the upper belt drive pulley, the bottom pulley guides the belt.. You sometimes have to wail on the thing a little bit to get it seated all the way. Just making sure.
Chris, good catch! No it was not fully seated. Took it apart this weekend, gave it a couple of wacks with the driver and a lead hammer, fixed it! You have a keen eye, thanks again.
Steve
Many of you probably know I've been building a new engine for my 18' cp gullwing. This boat is not a race boat and I tried hard to resist going to far in that direction. I don't want to be the fastest guy on the river, just wanted something that runs "good". I'm not a professional engine builder, just a garage hack, so don't be to critical. It is a 565ci all aluminum chevy with 335 AFR cnc heads, two AED 1050's, 14:1, Straub cam, and a bunch of other stuff.
Well I just dynoed the engine this weekend and I'm posting one of the dyno sheets for your review, along with a couple of pic's of the engine. I'd appreciate your feedback on what you think.
Roger, you're the best! I couldn't do all this stuff without your support. Anyone looking to dyno their engine needs to go see Roger Crawford, he is meticulous about the details. He won't let you hurt your engine either. I've known Roger for over 20 years and I'll stand by him forever!! Not bad for an old guy His numbers are: Work (714) 871-1940, Cell (714) 813-3491.
Whats the difference? They are both solid mounted.
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Related Threads
?
?
?
?
?
Performance Boats Forum
2.1M posts
41K members
Since 2007
A forum community dedicated to performance boat owners and enthusiasts. Come join the discussion about offshore racing, performance, modifications, builds, classifieds, troubleshooting, maintenance, and more!