tunnel ram or not????

[riverbound]

Its winter time and now I am kicking around the thought of doing a tunnel ram/ dual carb setup. I was wondering what kind of performance gain I would see if any. Here is what I got. 460 ford .030 over balanced blueprinted, weiand stealth manifold, holley dp 750,logs, Msd 6al, Mallory dist. w/ petronix, d3ve heads.
I have already cut the engine cover so I'm not worried about height anymore. and obviously looks are a concern, this is what it looks like now.
http://www.***boat.com/image_center/data/520/681IMG006-med.JPG

[Squirtin Thunder]

Check your user CP
Jim

[Tinkerer]

Best gain would be to get rid of the log exhaust manifolds.
do that first before anything else - Your exhaust is what is holding your engine back.
Get the header exhaust and then the other stuff will help.
with engines everything has to flow the same.
If one thing is restrictive it will restrict the entire engine.
Exhaust first then heads then cam then intake and carbs.
Everything must match.

[riverbound]

Sorry I forgot about the cam, I have the Isky "jetboat" cam.

[Squirtin Thunder]

:boxingguy

[riverbound]

Thanks for the info ST.

[LakesOnly]

...I am kicking around the thought of doing a tunnel ram...I was wondering what kind of performance gain I would see.
460 ford .030 over balanced blueprinted, weiand stealth manifold, Isky jet boat cam holley dp 750,logs, Msd 6al, Mallory dist. w/ petronix, d3ve heads.
Let me first say that I love my tunnel ram and don't intend to change back to single carb, as I am quite happy.
That being said, you should know that your fuel consumptiion is going to absolutely skyrocket. For more than an entire season, you will be astonished at the how much more often you must refuel. There's really no way around it. (In my case, I can drain both 11-gallon tanks in an hour or so, if I really want to...)
The power increase you see with your specific build & setup will be negligible. You may not even see a significant increase in speed. I think you may even get comparable results with a bigger single carb on your current manifold, and at the same time, maintain some of your current fuel usage rate...
LO

[Squirtcha?]

Let me first say that I love my tunnel ram and don't intend to change back to single carb, as I am quite happy.
That being said, you should know that your fuel consumptiion is going to absolutely skyrocket. For more than an entire season, you will be astonished at the how much more often you must refuel. There's really no way around it. (In my case, I can drain both 11-gallon tanks in an hour or so, if I really want to...)
The power increase you see with your specific build & setup will be negligible. You may not even see a significant increase in speed. I think you may even get comparable results with a bigger single carb on your current manifold, and at the same time, maintain some of your current fuel usage rate...
LO
Amen to that Paul. I'll echo everything he just said. I swapped mine over last year. Got a big goose egg for gains. My setup is very similar to yours riverbound. Would I swap back to a single..............No. Why????????? hell I don't know.........what's with all the trick questions?
Also agree wholeheartedly with Tinkerer. You'd probalby pick up 200-300 rpm by going to headers.

[moneysucker]

With an exposed engine I would advise a tunnel ram. Not for performance, just looks. The extra fuel consumption is worth it there but with your current set up, it is clean now and like they said exaust is a better way to spend your money at this point.

[TIMINATOR]

Tell us which Isky jetboat cam you have and the rpm you are running now. My vote, do the headers,let us help with a different cam(i'll explain when you tell us what it is),change carb to an 850? depending on rpm. We have some mods to tunnelrams to make them work better at typical jetboat rpms, if you go that way.Me? I prefer the "sleeper image", single carb, no scoop, thru transom headers, but thats just me. TIMINATOR

[Squirtin Thunder]

Tell us which Isky jetboat cam you have and the rpm you are running now. My vote, do the headers,let us help with a different cam(i'll explain when you tell us what it is),change carb to an 850? depending on rpm. We have some mods to tunnelrams to make them work better at typical jetboat rpms, if you go that way.Me? I prefer the "sleeper image", single carb, no scoop, thru transom headers, but thats just me. TIMINATOR
Tim,
I explained all that to him last night about his cam and valve size. We desided to make the boat a bit more eficiant then deal with the engine down the road. He is another guy with a BBC grind on a BBF, old tec.
Jim

[malcolm]

Well then maybe you should try posting in the THREAD! ;)

[Squirtin Thunder]

Well then maybe you should try posting in the THREAD! ;)
Actually check out best bang for the buck in gear heads. Its all over there.
Jim

[hack job]

Tim,
I explained all that to him last night about his cam and valve size. We desided to make the boat a bit more eficiant then deal with the engine down the road. He is another guy with a BBC grind on a BBF, old tec.
Jim
i didnt know that you were part owner of his boat. :confused: i would stay with the wieand stealth and maybe go to a bit bigger carb. the tunnel ram more than likly will not do any thing for you.( besides waste gas) ;)

[Squirtin Thunder]

i didnt know that you were part owner of his boat. :confused: i would stay with the wieand stealth and maybe go to a bit bigger carb. the tunnel ram more than likly will not do any thing for you.( besides waste gas) ;)
I take a personal interest in there boats. Have you ever been asked what you would do by a customer ???? Did you and that customer wiegh all the options. Well thats what we did pros and cons. No I am not part owner but.....
Thanks for reminding me where I am
this isn't RJBs **** I though I was lost
Jim

[77468sleekcraft]

Tunnel Rams Are Definatly The Way To Go.or Maybe I Am Just Being Biased. Hmmmmmm.. ;)

[Squirtin Thunder]

Cool factor yes 100% fuel efeciant no set up right with the right impeller maybe, Family boat no !!! By the way I am going to a T ram very soon !!!! I am also running a Berk "B-" impeller.
Ford Cool Factor !!!

[Mr.&Mrs.Budlight]

Unless you are going for all out performance or the awe factor. I would say the best carb for all around performance on a mild big block was a 800 doublepumper spreadbore. It was easy on gas in cruise and great on wide open throttle. I'm just not sure if Holley still makes it. Budlight

[flat broke]

I'm going to go against what EVERYONE has said on here. Unless you are willing to dedicate a significant amount of $$ and time to make that 18 haul ass, just save your $$ for gas. The tunnelram on your pagckage isn't going to be worth anything. Doing the kinds of changes you might be looking at with a shoe and rideplate will do a little, but that hull needs balls to move and work past its porpoise issue. I don't know what youre running right now, but I'd be willing to guess that your right at 60 on a good day. Going after a boat like that with the mindset of "a little faster" is the surest way towards disapointment and wasted $$. The problem with "a little faster" is that you always just get "a little faster", then you want to go "a little faster".
Cruiser hulls are a different breed. They weigh more, they ride wetter, and especially the Spectra and all variants thereof, take LOTS of work in the motor, pump, and bottom departemnt to air out and haul ass. Look under your boat and tell me how many strakes run to the transom... I know the answer, but you seeing it is a lot more effective than anyone telling you. You can also look here (http://www.spectramarine.com/spectrabrochures/spectra18/pink_large.gif) I'm not dogging the hull. I have a 20 and love it, but I also know how they work and why what makes them a good cross drive platform, doesn't lend them to tremendous speeds with a jet.
Before you change ANYTHING on that boat, ask yourself some very basic questions and answer honestly. How fast will make you happy, how much holeshot do you need, how much money do you want to spend, and lastly, how much time do you have.
Myself and many others have dumped thousands chasing undefined speeds and acceleration qualities. Only after I defined what would make me happy, and bulit accordingly did I start to feel that my money and effort was well spent. You have a very nice 18, but its just that, a Spectra 18. The cost to make a station wagon go 150mph is a lot more than if you just buy a 150mph capable car. The same rule applies to our boats.
Pump efficiency is important, and for that I think Squirtin Thunder may have had some good advice for you. But pump mods that might be good for 5mph in a shallow V 18-19'er will net you considerably less in a cruiser. The bottom line is to define your goals and then ask the same questions.
Good luck,
Chris

[Mr.&Mrs.Budlight]

Thanks Chris, Didn't you read my post. Not everyone thought it's a great idea. Maybe you don't like 800 holley dp spreadbores. Ever own one? Sorry, I felt I made a decent recomendation. I'll shut up now. Budlight :confused:

[flat broke]

Thanks Chris, Didn't you read my post. Not everyone thought it's a great idea. Maybe you don't like 800 holley dp spreadbores. Ever own one? Sorry, I felt I made a decent recomendation. I'll shut up now. Budlight :confused:
Easy there. For one I typed my post over an hour period between issues at work, so your post came while I was still typing. Second it's the little changes here and there that later get abandoned when you go big that constitute a lot of the lost money in piece by piece build ups without a plan. Nowhere did I say your or anyone else's sugestions were bad, just that I've found the best course of action to be... Decide what you want from the boat in whole. Then figure out the best way to get there. I didn't say a negative word about about carbs, manifolds, pumps etc. I just gave some insight on the process of improving something.
I'm a good guy, as evidenced by some pictures that will hopefully come out in a magazine at some point in time showing some guys manhandling a certain rootbeer colored CP onto a trailer just north of needles ;) I certainly didn't intend to discount anyone's opinion including yours, so its probably just a misscommunication.
Not to hijack the thread, but how's the new layup comming? Will we see you at the CBBB this year?
Chris

[Squirtin Thunder]

The bad thing about this whole deal is that his stuff is almost brand new. I directed him to concetrate on the pump. Efficancy will help him more right now. He is going with the Lightning headers. The engine was just built not too long ago. So after he gets the thing to mover the water better then the carb and the cam and rockers will be next. And probably some head work being the heads are bone stock D3s.
Jim
Everyone has give great advise. Budlight I have used those carbs and yes they are almost as cool as the 950 3brl.

[77468sleekcraft]

SERIOUSLY I ONLY THINK TUNNEL RAMS LOOK WAY COOLER ON A BOAT APPLICATION,BUT ON MY CAR ,--THE TOY I REALLY WANT TO MAKE GOOD HP.I THINK A GOOD HIGH RISE SINGLE PLENUM AND A HOLLEY 850 WITH SOME TLC, IS THE WAY TO GO.... :D

[Mr.&Mrs.Budlight]

Flatbroke, Sorry, I just keyed off the statement" I'm going to go against EVERYONE here" the rest of your post was very good. my apologies to you. Budlight :(

[Jeanyus]

Flatbroke, Sorry, I just keyed off the statement" I'm going to go against EVERYONE here" the rest of your post was very good. my apologies to you. Budlight :(
Go with the tunnel ram, with good carbs I dont think it will hurt performance.
I have a small engine (427) and I'm turning a b impellor 5500 rpms for a top speed of 78 mph. If you are looking for mpg, theese vacume secondary 600s amaze me, when I go to put gas in it it never takes as much as I thought.
I thought my tanks were empty at ming, turns out I had 15 gallons in the boat.
SPAM ALERT THESE 600s are for sale, they have been run about 8 times,
$ 250.00.
http://www.hotboatpics.com/pics/data/500/5859bassettscoop.jpg

[Squirtin Thunder]

Go with the tunnel ram, with good carbs I dont think it will hurt performance.
I have a small engine (427) and I'm turning a b impellor 5500 rpms for a top speed of 78 mph. If you are looking for mpg, theese vacume secondary 600s amaze me, when I go to put gas in it it never takes as much as I thought.
I thought my tanks were empty at ming, turns out I had 15 gallons in the boat.
SPAM ALERT THESE 600s are for sale, they have been run about 8 times,
$ 250.00.
http://www.hotboatpics.com/pics/data/500/5859bassettscoop.jpg
You flipppppin goooooooooooon !!! Next time why don't you just fill them up all the way ????
Jeassssssssss can't take you anywhere !!!
That is about 5mph you gave up !!!
Jim

[Jeanyus]

Dohhhh! Stupid boat sips on gas like a Honda car.

[malcolm]

I was reading for the tunnel ram info and didn't even realize we have the same boat! Mine has a weaker engine though. Headers made a huge difference on my small block Olds. I gained 300 RPM and 2 MPH. Of course with my 403, that only gets me to 53. I'm working on a big Chevy for next year, looking for 60. I'm shopping for a tunnel ram for it also, but only so you can see something over the deck. :D

[riverbound]

Thanks for all the helpful info. Looks like exhaust will be next on my list, does anyone know where I can find some used lightnings?

[probablecause]

Make sure your pump is running efficiently. I had a new engine put in and ran it for a season which was a big difference between the old dog. However, once the pump was reworked, holly $hit! If you pump is only running at 75% efficiency, you are throwing away 25% of your engines ooommmppphhh. Just my two cents.

[riverbound]

pump was just rebuilt about 2 trips before the new engine.

[hack job]

Thanks for all the helpful info. Looks like exhaust will be next on my list, does anyone know where I can find some used lightnings?
dude not to come off like a ass but the used lighting deal is going to be really hard to find, and if you do some of the olders ones were made out of mild steel on both pieces so they rust from the inside and you would never know till its too late. :frown:
i know you have a ford and that they want 2k for a set of new ones but its money well spent. if you need used chevy to ford adpeters i have a set for sale for 75 they are in great shape . i went to a head that is chevy exhaust pattern and so i no longer need them. any how good luck and remember spend once, cry once;)

[Chris J]

For what it worth. I picked up 8mph and 600 rpm. When I switched from a 850DP to a tunnel ram w/650. My setup: stock WJ with a stock 461BBC w/cam and through logs. Ran 45mph at 4200rpm. After tunnel ran 53mph at 4800 rpm. (Don't worry I just sent the impleller out)
On my drag car I picked up over .5 second with a similar swap. (850bp to 660s). I later switched to a worked over 1050 dominator and still LOST about .1 seconds.
Bottom line a tunnel ram WILL make more power at higher RPM which is perfect for a jet boat, since low end touque has no value on a jet, and fuel consumption should only come into play when you uses your added HP. So you really don't have to sacrifice anything. If you don't see any gains start fine tunning!!
Just an observation: The average dude at the ramp may not notice (or even like) your headers, but they always comment on the tunnel ram. Unfortunatly some lakes ban OT headers or any exhaust modifications. I've actually been questioned by the sheriff if my logs were stock.