SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: capogniracing on January 01, 2015, 11:06:41 PM
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Ok guys need some opinions, I have a approx. 400 lb 18 California performance. My current motor set up is a 468 8.5-1 running 8lbs boost with merlin iron heads and 2 850 carbs. My bebate is a nitrous motor or putting heads on my current set up. Only because of weight. I personally love blowers and die heart blower guy but seems to me all the fast wingers have nitrous motors. Appreciate all opinions
"RTCP"
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Ok guys need some opinions, I have a approx. 400 lb 18 California performance. My current motor set up is a 468 8.5-1 running 8lbs boost with merlin iron heads and 2 850 carbs. My bebate is a nitrous motor or putting heads on current set up. Only because of weight. I personally love blowers and die heart blower guy but seems to me all the fast wingers have nitrous motors. Appreciate all opinions
"RTCP"
"RTCP"
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orrrr twin turbo 555?
(https://www.socaljetboats.com/proxy.php?request=http%3A%2F%2Fi275.photobucket.com%2Falbums%2Fjj313%2FHass828%2FHPIM2500.jpg&hash=1bae69d0fa057d5ea378d2b28ee104ce7f2e9032)
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orrrr twin turbo 555?
(https://www.socaljetboats.com/proxy.php?request=http%3A%2F%2Fi275.photobucket.com%2Falbums%2Fjj313%2FHass828%2FHPIM2500.jpg&hash=1bae69d0fa057d5ea378d2b28ee104ce7f2e9032)
ha ha that would be nice. I'm only debating nitrous be cause there is a pretty sweet deal on PB for a nitrous motor.
RTCP
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Weigh a 1471, inter cooler and a pair of dominator. Then weigh a digger kit that makes 500 hp with a full bottle, single carb manifold and single dominator and get back with me. The only place I think the have the advantage on a river boat the cool factor just don't lose the cool factor by lining up against wrong NOS boat. You may get your shorts yanked down. Most importantly they are always bigger and badder of both. If your a blower guy stick with the blower. After all 100 mph is very respectable.
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That was fogger kit my phone does not like that word
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Weigh a 1471, inter cooler and a pair of dominator. Then weigh a digger kit that makes 500 hp with a full bottle, single carb manifold and single dominator and get back with me. The only place I think the have the advantage on a river boat the cool factor just don't lose the cool factor by lining up against wrong NOS boat. You may get your shorts yanked down. Most importantly they are always bigger and badder of both. If your a blower guy stick with the blower. After all 100 mph is very respectable.
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We need to get your boat back together and see what this laughing gas stuffs all about. My question is a 700 hp na motor with a 250 shot keep up with a 950 hp blower motor??
"RTCP"
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"RTCP"
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It just basic math hp does not know how it's made. Your setup will determine what you will get from a 250 shot
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Another factor torque lines?!? Do nitrous motors compare to a roots??
"RTCP"
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If I were you, I would loose the heads and go with an aluminum head like Brodix or dart. You'll gain some hp and Loose some pounds. Wile your at it, take that 468 and turn it into a 496???
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If I were you, I would loose the heads and go with an aluminum head like Brodix or dart. You'll gain some hp and Loose some pounds. Wile your at it, take that 468 and turn it into a 496???
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This will definitely be a considered option 👍👍
"RTCP"
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I know that blower motor jets like a larger cut of impeller than comparable N2O boats.
Regarding weight, seems that about 70lbs = .1 second. Here is a recent thread on that brand X forum that reinforces this belief http://www.performanceboats.com/jet-boats/#/forumsite/20586/topics/260913
The aluminum heads should be a given and will allow you to run an additional pound of boost or an additional point of compression (NA). Each application will work best with application specific porting and valve sizing. Keep in mind that NA/N2O flow really wakes up with larger bores starting at 4.375 diameter. Boosted, smaller valves can flow more with less shrouding by smaller bores. Either way, a good flowing exhaust is required to handle the increased volume of combustion residuals.
Either engine can benefit from increased flow that corresponds with a larger cylinder bore, but a larger bore is also greater surface area that can have greater tendency for detonation.
I am a firm believer in starting with a clean slate with a new engine build. You will have less compromises and you end result will be more favorable. And you can continue to enjoy your current engine, new heads or not.
Cheers,
Joe
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I know that blower motor jets like a larger cut of impeller than comparable N2O boats.
Regarding weight, seems that about 70lbs = .1 second. Here is a recent thread on that brand X forum that reinforces this belief http://www.performanceboats.com/jet-boats/#/forumsite/20586/topics/260913
The aluminum heads should be a given and will allow you to run an additional pound of boost or an additional point of compression (NA). Each application will work best with application specific porting and valve sizing. Keep in mind that NA/N2O flow really wakes up with larger bores starting at 4.375 diameter. Boosted, smaller valves can flow more with less shrouding by smaller bores. Either way, a good flowing exhaust is required to handle the increased volume of combustion residuals.
Either engine can benefit from increased flow that corresponds with a larger cylinder bore, but a larger bore is also greater surface area that can have greater tendency for detonation.
I am a firm believer in starting with a clean slate with a new engine build. You will have less compromises and you end result will be more favorable. And you can continue to enjoy your current engine, new heads or not.
Cheers,
Joe
I would love to start a completely new build, bottom line is I have about 7k set aside and want to get the best result. Only reason for even considering a nitrous set up is Andy Ralls has a screaming deal for a nitrous motor and it could be within that 7k budget. I have yet to give him a call and find out any hp or what impeller he ran at what rpms. Just wanna make the right choice and get the most for money.
RTCP
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Just for fits & shiggles, remember on a bad weather day, the blower makes its own atmosphere, nitrous can't. You've got a great setup as is, stud the top, new heads, give yourself a lil' more boost, and I think you'll be happier.
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Just for fits & shiggles, remember on a bad weather day, the blower makes its own atmosphere, nitrous can't. You've got a great setup as is, stud the top, new heads, give yourself a lil' more boost, and I think you'll be happier.
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Thanks chrisx2, I'm really leaning toward that opinion. Heads and a lil more boost should do the trick.
"RTCP"
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I know that blower motor jets like a larger cut of impeller than comparable N2O boats.
Regarding weight, seems that about 70lbs = .1 second. Here is a recent thread on that brand X forum that reinforces this belief http://www.performanceboats.com/jet-boats/#/forumsite/20586/topics/260913
The aluminum heads should be a given and will allow you to run an additional pound of boost or an additional point of compression (NA). Each application will work best with application specific porting and valve sizing. Keep in mind that NA/N2O flow really wakes up with larger bores starting at 4.375 diameter. Boosted, smaller valves can flow more with less shrouding by smaller bores. Either way, a good flowing exhaust is required to handle the increased volume of combustion residuals.
Either engine can benefit from increased flow that corresponds with a larger cylinder bore, but a larger bore is also greater surface area that can have greater tendency for detonation.
I am a firm believer in starting with a clean slate with a new engine build. You will have less compromises and you end result will be more favorable. And you can continue to enjoy your current engine, new heads or not.
Cheers,
Joe
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At what psi should you o ring??! I was always told above 12. I will also be staying with MLS head gaskets. And am currently studed.
"RTCP"
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Haven't played with nitrous too much, but it would seem to me that a blower deal would be way more consistent. By consistent I mean it is simpler to get Stoichiometric numbers under almost any weather condition and altitude.
I would push for aluminum heads and reverse the water flow (heads first).
I have always heard the 12lbs. rule as well, although what would it hurt to do it at lower boost numbers? (answer;, nothing but the wallet)... :sly:
The thing I dislike most about nitrous is that it just seems so temporary to me. But then again, you have to realize that I came up through the marathon world, our junk had to run for an hour at a time at a setting of balls out. Not just a handful of seconds. Makes it a different game all together.
JMHO
GT
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Another factor torque lines?!? Do nitrous motors compare to a roots??
"RTCP"
No... IMHO the roots will have a torque curve that falls off as the engine speed gets passed a certain point. Because the faster the blower spins, the more HP it requires. IMHO perfect for a jet application, because you don't want to spin a whole bunch of RPM to begin with. (debatable, but I wont go there right now).
As for the nitrous deal, you are only limited by the volume/bottle pressure. So it's really an unfair contest, the N2o dealio will only sustain it's performance as long as the system charge will keep up. Cold bottle/weather, less performance/sustained bottle pressure. The blower however can run back to back to back runs, even in a hot lap situation, especially if you injected it on alcohol... 8)
GT
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No... IMHO the roots will have a torque curve that falls off as the engine speed gets passed a certain point. Because the faster the blower spins, the more HP it requires. IMHO perfect for a jet application, because you don't want to spin a whole bunch of RPM to begin with. (debatable, but I wont go there right now).
As for the nitrous deal, you are only limited by the volume/bottle pressure. So it's really an unfair contest, the N2o dealio will only sustain it's performance as long as the system charge will keep up. Cold bottle/weather, less performance/sustained bottle pressure. The blower however can run back to back to back runs, even in a hot lap situation, especially if you injected it on alcohol... 8)
GT
That is some good info! Thanks GT. I think I might just keep the blower. I'm pretty set to just change heads and maybe stroke it to a 496. And I'm with you on O ringing. If its appart might as well do it right. I'm not really looking to run more than 10lbs and not sure if didn't hi helix I could get any more efficient power. And plans are to also add a intercooler. I'm looking to get around 950-1000hp. I will also be running a AB impeller. All I'm looking for is to give a couple guys a run. I know ill never be the fastest but I also don't wanna have my a$$ handed to me every time lol
"RTCP"
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That is some good info! Thanks GT. I think I might just keep the blower. I'm pretty set to just change heads and maybe stroke it to a 496. And I'm with you on O ringing. If its appart might as well do it right. I'm not really looking to run more than 10lbs and not sure if didn't hi helix I could get any more efficient power. And plans are to also add a intercooler. I'm looking to get around 950-1000hp. I will also be running a AB impeller. All I'm looking for is to give a couple guys a run. I know ill never be the fastest but I also don't wanna have my a$$ handed to me every time lol
"RTCP"
When I took my blower to be freshened up at Littlefield, they would not consider a hi-helix for a gasoline application. Alcohol only :(
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When I took my blower to be freshened up at Littlefield, they would not consider a hi-helix for a gasoline application. Alcohol only :(
Ya I heard the same thing. I know of a few drags guys that have done it on gas but it appears to be a drag only application. 👎
"RTCP"
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When I took my blower to be freshened up at Littlefield, they would not consider a hi-helix for a gasoline application. Alcohol only :(
I would say an HH would be OK with extensive bowl work and detailing and a properly set up shoe and loader. Once the hull moves five feet, I would call the HH issues moot.
Then again, may just be me.
We got to play with a custom high lift impeller years ago, all I remember is the bowl pressures were higher at lower RPM and fell off at speed (I read into that to be severe cavitation). The HH impellers increase the torque demand in the middle, (read; more bite).
I am still not sold on the idea of High Helix impellers. Seems to be some majorly contradicting results floating around out there.
Load it, straighten it and control the restriction on the nozzle, that is where the science is. JMHO
Make sure the impeller is enhanced for the given RPM and that the bowl reflects the same enhancements and it negates anything an HH can do..... Hope I didn't strike a nerve.
GT
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Hi-helix rotors require a new case and possibly a new manifold. Rotors have side strips to facilitate rotor to rotor sealing for alcohol and are clearanced tighter. I hear that the side strips create too much heat in a gas application.
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I would say an HH would be OK with extensive bowl work and detailing and a properly set up shoe and loader. Once the hull moves five feet, I would call the HH issues moot.
Then again, may just be me.
We got to play with a custom high lift impeller years ago, all I remember is the bowl pressures were higher at lower RPM and fell off at speed (I read into that to be severe cavitation). The HH impellers increase the torque demand in the middle, (read; more bite).
I am still not sold on the idea of High Helix impellers. Seems to be some majorly contradicting results floating around out there.
Load it, straighten it and control the restriction on the nozzle, that is where the science is. JMHO
Make sure the impeller is enhanced for the given RPM and that the bowl reflects the same enhancements and it negates anything an HH can do..... Hope I didn't strike a nerve.
GT
I thought he was talking about a hi-helix blower where the rotors have a 120 degree twist instead of the standard GMC 60 degree twist.
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I thought he was talking about a hi-helix blower where the rotors have a 120 degree twist instead of the standard GMC 60 degree twist.
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Just reread the post... maybe, I failed English... LOL
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I would say an HH would be OK with extensive bowl work and detailing and a properly set up shoe and loader. Once the hull moves five feet, I would call the HH issues moot.
Then again, may just be me.
We got to play with a custom high lift impeller years ago, all I remember is the bowl pressures were higher at lower RPM and fell off at speed (I read into that to be severe cavitation). The HH impellers increase the torque demand in the middle, (read; more bite).
I am still not sold on the idea of High Helix impellers. Seems to be some majorly contradicting results floating around out there.
Load it, straighten it and control the restriction on the nozzle, that is where the science is. JMHO
Make sure the impeller is enhanced for the given RPM and that the bowl reflects the same enhancements and it negates anything an HH can do..... Hope I didn't strike a nerve.
GT
I believe me and joe were talking about blowers. And for pump I have a full kilt built MPD - Double drilled bowl and droop, ss AB impeller, inducer, AQ shaft, fully detailed bowl, droop, blue insert, back cut shoe, ride plate, and of course loader. Guy I bought boat from spent many hrs with jack setting up, and takes a set ok for a river boat.
"RTCP"
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I believe me and joe were talking about blowers. And for pump I have a full kilt built MPD -ss AB impeller, inducer, AQ shaft, fully detailed bowl, droop, insert, back cut shoe and of course loader. Guy I bought boat from spent many hrs with jack setting up, and takes a set ok for a river boat.
"RTCP"
1000 HP on a AB will be spooky.... ;)
As for Blowers, you definitely don't need to go HH, unless of course my injected on alcohol comment got you to thinking... :sly:
I have a friend that did some time with BDS, at that time, hard anodizing and billet rotors were all the rage... Things have not changed much in the GM huffer world...
How many RPM are thinking you will need to run? I can tell you that everything will run out of steam above 6,200...
GT
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1000 HP on a AB will be spooky.... ;)
As for Blowers, you definitely don't need to go HH, unless of course my injected on alcohol comment got you to thinking... :sly:
I have a friend that did some time with BDS, at that time, hard anodizing and billet rotors were all the rage... Things have not changed much in the GM huffer world...
How many RPM are thinking you will need to run? I can tell you that everything will run out of steam above 6,200...
GT
I completely agree on 6200. My boat runs hard up to about 5900 -90 mph right now and then the mph slowly creeps after that. Would you recommend a impeller change or I am thinking the added hp with heads, ect will get me through that.
"RTCP"
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Which heads are you thinking? Im not sure you will see an increase in HP from just the head change. You might even lose HP if you don't step up the overdrive. Just going to a larger head with no other changes will cause a drop in boost as it is a greater volume to fill. Aluminum heads lose a lot of combustion chamber heat. There is also some debate that the boost will drop with better flowing heads. There is also a rigidity factor that is preventing me from switching to aluminium. My engine with iron heads rarely changes lash settings compared to my friend's engine with aluminum heads. I am really curious of your outcome. I have never had the opportunity to run multiple sets of heads on the same engine.
I have a friend who worked at Pfaff Racing Engines when a customer ordered two blower engines and told them to design the whole program. The decision to build one with their standard head (for the application) and one with an aggressive (LARGE) port size was made. The engine with the large heads was down on power and responsiveness.
Hmmmm, how much do you want for your Merlins?
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Which heads are you thinking? Im not sure you will see an increase in HP from just the head change. You might even lose HP if you don't step up the overdrive. Just going to a larger head with no other changes will cause a drop in boost as it is a greater volume to fill. Aluminum heads lose a lot of combustion chamber heat. There is also some debate that the boost will drop with better flowing heads. There is also a rigidity factor that is preventing me from switching to aluminium. My engine with iron heads rarely changes lash settings compared to my friend's engine with aluminum heads. I am really curious of your outcome. I have never had the opportunity to run multiple sets of heads on the same engine.
I have a friend who worked at Pfaff Racing Engines when a customer ordered two blower engines and told them to design the whole program. The decision to build one with their standard head (for the application) and one with an aggressive (LARGE) port size was made. The engine with the large heads was down on power and responsiveness.
Hmmmm, how much do you want for your Merlins?
Oh you guys are killing me! I was thinking of some darts or afrs. And I'm sure added flow will make me step up overdrive. My current set up is 50/57 14%. So I do have a lil room but not much unless I get a bigger blower.
"RTCP"
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12.3% overdriven?
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12.3% overdriven?
I showed 14% on pulley chart. I am running 8mm pulleys
"RTCP"
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I showed 14% on pulley chart. I am running 8mm pulleys
"RTCP"
I came up with 14% too....
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Big on bottom = 14:1 over
Little on bottom =12.3:1 under....
GT
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Divide the drivER by the drivEN!
I will never forget that now
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Big on bottom = 14:1 over
Little on bottom =12.3:1 under....
GT
Would you say max overdriven with an intercooler and running 110 and a 8-71 before it becomes inefficient??
"RTCP"
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Would you say max overdriven with an intercooler and running 110 and a 8-71 before it becomes inefficient??
"RTCP"
First off, what motor? The same 468? An 8-71 turning 14% over I would think would make way more than 8PSI, closer to double that.... Then again, I could be FOS.
It is my personal opinion that the blower should be spun as slow as possible while giving you the boost you desire.
The efficiency drops like a turd into an outhouse when you get much higher than 25%, I would call that a point at which a larger blower is needed.
I dunno, probably every case is different, but something sounds funny.... To me anyway....
GT
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First off, what motor? The same 468? An 8-71 turning 14% over I would think would make way more than 8PSI, closer to double that.... Then again, I could be FOS.
It is my personal opinion that the blower should be spun as slow as possible while giving you the boost you desire.
The efficiency drops like a turd into an outhouse when you get much higher than 25%, I would call that a point at which a larger blower is needed.
I dunno, probably every case is different, but something sounds funny.... To me anyway....
GT
I have a Blower Shop blower with non stripped rotors. Might be in need of a service?!?!?
"RTCP"
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I have a Blower Shop blower with non stripped rotors.
"RTCP"
With a non stripped set up, the efficiency takes a poo earlier.... I still think that somehow you are short on pressure..
Any idea what camshaft?
GT
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With a non stripped set up, the efficiency takes a poo earlier.... I still think that somehow you are short on pressure..
Any idea what camshaft?
GT
I have no idea of lift, ect. Only thing guy told me is it's a clay smith and a is a solid cam. That is another reason why I'm kinda wanting to tear it down to see what's inside. I know it's a 4 bolt and has arp rod bolts based on putting a timing cover on to take a peek. And does have forged pistons.
"RTCP"
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Having your blower tightened up will make a huge difference. Without strips, you have clearance between the rotors and housing which translates into a lot of leakage. Contact Littlefield, Mooningham, Hampton, or your favorite "race" blower shop and have them clearance it for gasoline. Mert Littlefield has always treated me very well and since his passing, Littlefield Blowers still treats me very good, even though I am a nobody.
I'm willing to bet that you will have a whole new animal on your hands.
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Having your blower tightened up will make a huge difference. Without strips, you have clearance between the rotors and housing which translates into a lot of leakage. Contact Littlefield, Mooningham, Hampton, or your favorite "race" blower shop and have them clearance it for gasoline. Mert Littlefield has always treated me very well and since his passing, Littlefield Blowers still treats me very good, even though I am a nobody.
I'm willing to bet that you will have a whole new animal on your hands.
With you on littlefield, my dad has bought a couple blowers there and always sends them there to get serviced. I will probably be in contact with them in 2 weeks after TPM. And if your out there joe and wanna go for a ride let me know.
"RTCP"
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Having your blower tightened up will make a huge difference. Without strips, you have clearance between the rotors and housing which translates into a lot of leakage. Contact Littlefield, Mooningham, Hampton, or your favorite "race" blower shop and have them clearance it for gasoline. Mert Littlefield has always treated me very well and since his passing, Littlefield Blowers still treats me very good, even though I am a nobody.
I'm willing to bet that you will have a whole new animal on your hands.
Totally agree.
Literally the only people I have ever dealt with when it came to blowers was Blower Drive Service (BDS) in Whittier. That being said, I have never heard anything but good coming from Littlefield.
I would be willing to bet your current blower is pretty tired and ready for some help. According to my calculations, even without teflon, you should be well into the 12 PSI range at 6,000 RPM. If Clay Smith did your camshaft, I would doubt seriously that there is a whole bunch of unnecessary lift on the intake side. So unless you have puny carburetors, I would say I think I know where some of your budget needs to go.
GT
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Totally agree.
Literally the only people I have ever dealt with when it came to blowers was Blower Drive Service (BDS) in Whittier. That being said, I have never heard anything but good coming from Littlefield.
I would be willing to bet your current blower is pretty tired and ready for some help. According to my calculations, even without teflon, you should be well into the 12 PSI range at 6,000 RPM. If Clay Smith did your camshaft, I would doubt seriously that there is a whole bunch of unnecessary lift on the intake side. So unless you have puny carburetors, I would say I think I know where some of your budget needs to go.
GT
Currently running 850's. so I doubt that is the issue. But I will send blower in and start with that. And should probably buy a couple pulleys as well. Thanks guys I think I'm headed in the right direction.
"RTCP"
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And if your out there joe and wanna go for a ride let me know.
"RTCP"
I will be and I WANT!
Looking forward!
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Totally agree.
Literally the only people I have ever dealt with when it came to blowers was Blower Drive Service (BDS) in Whittier. That being said, I have never heard anything but good coming from Littlefield.
I would be willing to bet your current blower is pretty tired and ready for some help. According to my calculations, even without teflon, you should be well into the 12 PSI range at 6,000 RPM. If Clay Smith did your camshaft, I would doubt seriously that there is a whole bunch of unnecessary lift on the intake side. So unless you have puny carburetors, I would say I think I know where some of your budget needs to go.
GT
Currently running 850's. so I doubt that is the issue. But I will send blower in and start with that. And should probably buy a couple pulleys as well. Thanks guys I think I'm headed in the right direction.
"RTCP"
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I will be and I WANT!
Looking forward!
👍👍 you got it bud!!
"RTCP"
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Sweet!
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If it wasn't a 6 hour drive for me I would go to the TPM. Tried to get my buddy interested enough to fly down, but he has some sort of "thing" his wife wanted him to do LOL...
GT
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If it wasn't a 6 hour drive for me I would go to the TPM. Tried to get my buddy interested enough to fly down, but he has some sort of "thing" his wife wanted him to do LOL...
GT
Well same to you GT! I knew you were a lil ways away but if you end up making it down we can go for a hot lap.
"RTCP"
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Just out of curiousity,, I was watching the build of this boat as it came together thru pics u were posting, and ur iron Merlin's looked like oval ports? Am I wrong? I'd never build a pressure motor with ovals.. :banghead: kinda shooting urself in the foot, IMHO,,
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Not talkin shit, at all, I know the boat runs hard,, just an observation of part selection.. :thumbup:
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Just out of curiousity,, I was watching the build of this boat as it came together thru pics u were posting, and ur iron Merlin's looked like oval ports? Am I wrong? I'd never build a pressure motor with ovals.. :banghead: kinda shooting urself in the foot, IMHO,,
I did not build the motor. That's why I am wanting to do a head change.
"RTCP"