Winter Upgrades |
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TX Foilhead
Grand Poobah Joined: February-01-2009 Location: Kingsland TX Status: Offline Points: 2076 |
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Posted: September-29-2011 at 1:51am |
OK, the ProTec is on the list for the winter upgrade since it seems to be getting weak and is probably starting to cost a bit of increased fuel use. I'm getting a bit sluggish out of the hole and require more throttle to get the job done these days. While I'm at it I also need to to the manifold gaskets, and If anyone thinks it's a good idea I may do head gaskets as well while I'm there. The boat has 925 hrs and runs fine just a bit weaker than year past.
Here's the question. I'm thinking about adding a cam and intake while I do the ProTec. I don't need a motor rebuild and already have GT40 heads so I don't see a real reason th switch to the GT40P's. What intake and what should I look for in a cam? We run very little ballast and usually keep it below 30, I ride between 24 and 26 and the boat turns less than 3000 RPM's the majority of the time even when we have a full load of people. I'm not trying to build some crazy motor like Joe right now, that may happen down the road though, just want to liven up what I've got a bit. I'm also curious to know if an intake would be noticeable without the cam. I think I can slip a cam in without pulling the motor, having to pull the motor would be the deal breaker on the cam. Just eyeballing it, it looks like there is room if I pull the invertaflow I'll a few inches to spare. |
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eric lavine
Grand Poobah Joined: August-13-2006 Location: United States Status: Offline Points: 13413 |
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and a timimg set...that may be creating the lazy engine. yes you can do a cam in the boat.
for what the boat is used for, i would just do the distributor and pop the front cover, do the timing set and repair the intake leak.... now, unless you have a pocket full of money..... |
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"the things you own will start to own you"
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TX Foilhead
Grand Poobah Joined: February-01-2009 Location: Kingsland TX Status: Offline Points: 2076 |
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No intake leak that I know of, might be a little bit of a leak on the exhaust risers. I need to clean it up real good and watch it next time out. I checked the timing, which was OK, and changed the plugs last weekend and got real improvement. Carb seems to be working as well as it ever has, starts first try and idles perfectly with no help every time even when cold.
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Luchog
Grand Poobah Joined: April-17-2007 Location: Argentina Status: Offline Points: 2135 |
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I dont see a reason the change the intake and cam if you're not underpowered. The stock engine seems more than enough
I'd start by the ignition and timing set as Eric suggested, then MAYBE lap the valves. What prop are you turning? When people tell they never ran it over X rpms and/or are underpropped carbon build up on the valves is a common issue. It doesnt hurt to give the engine a hard run from time to time, it helps keeping it clean. |
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TX Foilhead
Grand Poobah Joined: February-01-2009 Location: Kingsland TX Status: Offline Points: 2076 |
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Acme 328 (12.5X15 I think). I can't remember the RPM's she used to turn, but I've always been able to run a solid 48 everytime, and on occasion have gotten to 49.5. The last few tries have been 42 to 43. Due to an issue with the drive shaft and the rudder being very close there is only one prop available for the Excel.
The power upgrade is more to have it when I do need it I realize that I won't use it most of the time. Occasionally someone asks for for more out of the hole, I could also use a bit more for the shows we do at the boat races. The course is very tight and every second we are wasting to get back to speed on the ends is not entertaining the crowd. We get a very limited number of tricks each pass being able to add 1 more would be a bonus, but I need to be able to either hold the speed on the very tight turn, or get it back quickly. The first year we used aboat that had a 496 the speed in the turns was about the same, but once aimed straight it almost instantly returned to speed. The people that run the race prefer the Excel because the wake doesn't swamp the boats they are trying to load into the water while we do our thing. I know some torque is what I'm looking for and stroker motor will be in the plans when it comes time for a rebuild. If there would be no benefit from a cam and intake upgrade when we need it then no use in doing it. I do realize that I don't need it the majority of the time. |
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TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21135 |
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An intake and cam upgrade would improve power across the band- holeshot and midrange power would be much better. The latter is what will help you accelerate out of a tight turn at speed.
I would expect about a 10hp increase with the intake manifold alone (barely worth it), but you'd probably be in the 320hp range with the cam and intake together, when matched properly to your GT40 heads. Whether or not you can swap cams in your v-drive Excel without pulling the engine is a good question- I cant answer that for you. I would recommend swapping out the timing set either way with a good double roller (like a Cloyes Tru Roller, ~$40) while youve got it apart. If doing both, Id go with a taller dual plane intake if you can fit it (like the Edelbrock Performer RPM or Weiand Stealth). Those will be 2.5" taller than stock. If you cant fit them, or only plan to do the intake, go with the regular Performer, which is ~1.5" taller than stock. If you do upgrade the cam, Id recommend getting one from Cam Reasearch. Be sure to run their recommendation by us before pulling the trigger, theyve been known to be on the conservative side. The difference youre seeing in performance (6+mph) is pretty significant... you may be right about the Protec being the culprit, but at the very least, Id be checking to make sure that the secondaries are coming in all the way as well. |
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TX Foilhead
Grand Poobah Joined: February-01-2009 Location: Kingsland TX Status: Offline Points: 2076 |
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No clearance issues, I think I have about 6 inches above the motor. I've eyeballed the space in the back and it looks like there is more than the length of the block between the block and the transom. It's really almost as easy to work on as a DD since the space was made for a BBC.
You may be right about the secondaries, speed runs are the only time I get into them, I don't think they open out of the hole. They aren't real easy to check because of a kill switch on the hatch and I'm a bit worried to run those speeds with the hatch open acting like a sail. I will look at them before I begin tearing into the motor once the hatch is removed. The holeshot and the extra throttle required is what I'm really noticing. We used to never need more than half throttle to get out, now we use 3/4 and with enough people we need the whole thing and more would be nice because that's still a bit slow. With plenty of power I can control when the newbies fly when learning to foil. I'm loosing that ability, as I have to move the throttle more its easier to over do it. Most people that know what there doing and are used to much bigger boats don't notice the Holeshot because I'm still as fast as the big boats. |
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Bri892001
Grand Poobah Joined: September-27-2008 Location: Boston MA Status: Offline Points: 4947 |
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I grabbed this snippet from here, a little more than halfway down the page, after the pictures of the secondary diaphrams: http://www.bob2000.com/carb.htm
I've heard or people mentioning a paper clip instead of the bread tie he talks about, but I guess better to not have metal clips randomly dropping somewhere. How to know if your vacuum secondaries are opening You can tell if your secondaries are opening by keeping them shut with a spring or other means. Test drive the vehicle. If performance is worse with the secondaries held shut, then they were opening when operating normally. Alternatively, tie a bread bag twist-tie onto the vacuum secondary shaft near the top where the shaft would move in to the housing, and see if it has moved after driving the car. Winging the engine in neutral does not work! Vacuum secondaries operate off engine rpm and load, not just rpm, and there just isn't enough airflow in a no-load situation to open the vacuum secondaries. |
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TX Foilhead
Grand Poobah Joined: February-01-2009 Location: Kingsland TX Status: Offline Points: 2076 |
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That's what I was thinking, they don't open until RPM's are up so they aren't adding anything out of the hole. I used to be able to hear them open, but I added a little sound insulation to the back wall behind the seat and now it's not so easy to hear. Good tricks though to check them without opening the hatch.
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BuffaloBFN
Grand Poobah Joined: June-24-2007 Location: Gainesville,GA Status: Offline Points: 6094 |
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Your description says you need a big block. Unless I turn tight, it holds where it is; cheapest perfect pass out there.
From what I've seen of V-drives, you don't want to try that cam change with the engine in the boat. I would want it turned where I could see it. |
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TX Foilhead
Grand Poobah Joined: February-01-2009 Location: Kingsland TX Status: Offline Points: 2076 |
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Most vdrives don't have the space, the Excel though is more like a DD without the pylon in the way.
If you have a spare Python to donate to the cause I'll give it a try! |
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TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21135 |
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Ha, Im not so sure about that, Greg. Ive found that with stock props, big and small block CC's tend to perform pretty similarly until you get to barefooting speeds- where the big blocks will slowly pull away. Actually, out of the hole, the small blocks hold an advantage. Probably due to the extra weight of the BB and the taller prop they have to spin to keep the revs down at WOT. Ask Ken and Eric how their drag race went a few years ago... BBC vs. SBF 2001's. |
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Luchog
Grand Poobah Joined: April-17-2007 Location: Argentina Status: Offline Points: 2135 |
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No one have said that. What Eric and I tried to say is that first you should check some basics on the engine tuneup and condition and then you can judge if you need/want more HP. now, do you need it cause you want it? or you want it cause you need it? |
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TX Foilhead
Grand Poobah Joined: February-01-2009 Location: Kingsland TX Status: Offline Points: 2076 |
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Too much is just enough, right? Some more would be nice even when it's running right. After the new prop I've always felt she did pretty good compare to other Vdrives with small blocks. I did drive a friends Tige 22ve the others day that changed my mind, not sure why, but came out of the hole like a rocket with just the basic Marine Power 350. I know the TAPS plate helps a bit, but I haven't noticed this when driving other Tiges. Even my friends 06 Xstar proped to handle 3500lbs of ballast wasn't like this boat even unloaded. I had to apologize for nearly pulling the handle out of his hands the first time. I get to drive another one Sunday, a new Z1 with the PCM 343 I'm thinking that one will be even more of a rocket. I can still get them easy on the top end though. : )
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TX Foilhead
Grand Poobah Joined: February-01-2009 Location: Kingsland TX Status: Offline Points: 2076 |
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OK, things are looking up a bit finance wise so I thought I would add this.
I know general consensus around here is to add the GT40p heads when upgrading the standard 240hp motor. Is there enough of a benefit to justify changing my GT40 heads out for some GT40p's. The car guys seem to think not or are undecided, but they are benifiting more at RPM's I'll never see, and they seem to have issues with the new location of the plugs in the GT40p's. |
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Bri892001
Grand Poobah Joined: September-27-2008 Location: Boston MA Status: Offline Points: 4947 |
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From what I've read the spark plug re-location of the "p" version is actually a benefit on the marine side. Because, our exhaust manifolds are a different shape and head a different direction.
But, also from what I've read, we may not see a difference between "p"s and regular GT-40s without other mods. In other words, if you have standard head, might as well go with the "p"s, if you already have non-p GT-40s, might as well keep them. Check out this thread: http://www.correctcraftfan.com/forum/forum_posts.asp?TID=23776&PID=302160#302160 Joe had a great description:
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Jllogan
Platinum Member Joined: May-18-2011 Location: canton, OH Status: Offline Points: 1728 |
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I understand why you say that if you cant fit an RPM or stealth to go with a regular performer but you also said "or if you only plan to do the intake" to just go with the performer. Why? They are the same price would there be a disadvantage or issue with putting a RPM or stealth on with a stock cam and gt40 heads? The reason I am asking is I am doing some winter upgrades as well. I have a set of gt40p heads on the way and I am shopping around for intakes. I would like to do the cam but dont want to commit under I see how much I end up spending on floor/stringers (another project). If the floor turns out to not eat up all my extra money I may drop the cam in. I figure I might as well do the intake especially as I have seen a couple edelbrock performers on craigslist for around 100 and it will already be off. |
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TX Foilhead
Grand Poobah Joined: February-01-2009 Location: Kingsland TX Status: Offline Points: 2076 |
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Yep, that's exactly what I heard from a few hours of searching car forums. I have no problems with my current plug location, that might be because I was used to needing 3 different wrenches on the Commander log manifolds so anything is easier. What I haven't heard is what exactly is the efficiency they are talking about? If that translates in to saved gallons per hour then might be worth while, I've heard it talked about but never explained. Anyway GT40p's seem to be very easy to come by and looks like this project may get done Thanksgiving since my regular crew will be out of town.
You're really good if you can have something left over doing the the floor and stringers. Lol. Took all my time and $$$ plus some. |
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Jllogan
Platinum Member Joined: May-18-2011 Location: canton, OH Status: Offline Points: 1728 |
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well Im still optimistic but am planning for the worst. From what i have been able to inspect its in ok shape. Im hoping it doesnt dissentegrate when I get in there. All of my lag bolts are not stripped and when I removed the gas tank the wood around the exhaust and the back of the stringers where still solid and the fiberglass wasnt even cracked. I have a few soft spots in the floor and I am hoping if I head it off now it wont turn into completely rotted stringers and wet foam. The jury is still out. Im sure Ill have updates.
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