Competition marine engine

[Diesel Freak]

Take a look at this!!!!



Might be something to try and mirror with the 12 valve, but add 200-300 HP to it at 4000 RPM



http://www.gce.cummins.com/mce/mce_QSB/assets/Fr91632.pdf

 

[RJaeken]

on plane is totally different than what it takes to get there. Before you are up out of the water, drag is huge.



A blown 540 chev big Block will crank out of the hole like a scalded cat... that is because it has the low end responce (assisted by the blower) to get the prop spinning, and lift the boat. You need some crazy fast spooling turbos to get this kind of responce from a diesel. Dont forget to factor in the added 200-300 pounds of engine.



What is the final drive ratio behind the 540? What prop are you running?



A good running B series with 600 crank HP will prolly have about 2/3 the rpm range of even a mild big block (as you know 600 HP is mild for a blown big block), so your out drive and prop will have to match.

Actually, I am the boatbuilder (www.raffshore.com)



We have build a billet alu step up gearbox from 1:2, this to make an RPM range from 1200 to 8000 rpm. Also this way we devide the massive torque to save the drive unit. We want to use a bravo style drive (IMCO). I have acces to whatever prop or gearratio I want.



The cummins isn't so much heavier then the BB blown chevy + on the water every wheight is devided by 4.



Al this we have covered, also the massive water to air intercooler is currently being welded.



At first I was discussing this with a very known porsche engine builder here in Europe. They are doing 3. 6 twin turbo's with 700HP+. As he is my friend I asked his advice, showed him some twin turbo setup's from the ATS, Piers and BD websites, and then he came up with the 2 parallel turbo's...



I really want to go true with this because petrol here is very expensive. If I can get this thing running I will sell boats and engines.



Lot's of people tell me that twin parallel has been tried and tested but I cannot find anything on all the cummins forums about this.

 

[Diesel Freak]

well, give it a shot. who knows, you may indeeed prove the naysayers wrong.



If you do use the GT30R, start with the smallest exhaust housing you can find, then go up from there. Intercooling will be the key to keeping EGT at useable levels with 45 PSI of boost. With twin GT30 turbos, you should be able to shed enough heat with the intercoolers to use all the available 90 lbm/minute they can provide. Gotta love that unlimited heat sink of the ocean!!!



The big reason Compound turbos are used on Cummins Land based vehicles is that intercooling is not as effective, and we want to use high boost pressures to overcome that drawback.

 

[Forrest Nearing]

horrible idea IMHO... compounds are so much more efficient...



your turbo guru doesn't sound like a DIESEL guru IMHO

 

[Diesel Freak]

hey do you know this guy?



Arto Lehikoinen: Product Manager, Measuring Instruments, PEREL OY

 

[Diesel Freak]

horrible idea IMHO... compounds are so much more efficient...



your turbo guru doesn't sound like a DIESEL guru IMHO

if the guy can do it, more power to him.



if he can get air temp out of the intercoolers back to ambient or below (quite possible when using sea water as the heat sink), it is possible. The density ratio will be there!!!!



A density ratio of 4:1 can support almost 500 HP with EGT < 1200F

 

[RJaeken]

no, don't know him, why?



To forrest : you are right, he is not a diesel guru...



but, I am the most impossible guy, I always want something that others haven't. That was the main reason to start building boats.



So nobody has any contacts about these parallel stuf?



Also, although a GT30 is mayby the same seize as a HX35, with the smallest exhaust housing they should be OK.



And It would look cool.

And I can use 2 3cil exhaust housings, which will be easier To make watercooled if I ever want to make a pleasure boat.

 

[RJaeken]

Oh yeah, I am open to other turbo options, mayby twin K24's?

 

[Diesel Freak]

no, don't know him, why?



To forrest : you are right, he is not a diesel guru...



but, I am the most impossible guy, I always want something that others haven't. That was the main reason to start building boats.



So nobody has any contacts about these parallel stuf?



Also, although a GT30 is mayby the same seize as a HX35, with the smallest exhaust housing they should be OK.



And It would look cool.

And I can use 2 3cil exhaust housings, which will be easier To make watercooled if I ever want to make a pleasure boat.

Just currious... . someone over in your neck of the woods that was asking about turbo stuff a while back.



About the exhaust housings... . I really do not know if they will work, you may only be able to get 15-20 psi of boost out of the thing (if you are lucky). Remember that you are deviding the exhaust energy in half, and trying to drive turbo the same basic size of the stocker with it.



Just don't want you spending all that money on a pair of turbos, and then not being able to get them to spool worth a darn.

 

[Diesel Freak]

Oh yeah, I am open to other turbo options, mayby twin K24's?

not gonna do it!!!



YOU NEED 45 PSI OF BOOST AT AMBIENT TEMP (70F OR LESS) under full load

 

[Forrest Nearing]

the reason I mention being a diesel gurus is that most gasser guys can't wrap their heads around the fact that our engines don't flow air for squat!!!



they need BOOST!!!!!!!



and a single turbo just doesn't cut it... especially under continuous load...



you can make nice numbers on a big single (I'm shooting for 600+rwhp on a single) but EGT's are HIGH



just run compound twins and enjoy!!

 

[Diesel Freak]

yep, he would be better off with a mild set of compound twins... since we know it can be done that way.

 

[RJaeken]

the reason I mention being a diesel gurus is that most gasser guys can't wrap their heads around the fact that our engines don't flow air for squat!!!



they need BOOST!!!!!!!



and a single turbo just doesn't cut it... especially under continuous load...



you can make nice numbers on a big single (I'm shooting for 600+rwhp on a single) but EGT's are HIGH



just run compound twins and enjoy!!

I was just checking out your pictures, what turbo's are you running? (or planning on running)



Also, I see combo's of HX35 or HX40 with HT3B. Why would a 40 combo make more boost then the 35?



The 35 should spool faster and when the wast gate opens it's the big one doing all the work, correct?

 

[Forrest Nearing]

the turbos work together...



I'm going with a 66mm single... it will run hotter, but it will make some good numbers, and I have NO time to tinker anymore



a lot of kits use a larger top turbo to prevent choking the engine off, but yes, I'm a fan of a smaller (HX35) top w/ a big wastegate...