Twin Turbo Small block Chevy

[BrendellaJet]

I've got a jet boat that needs an engine, and happen to have a fresh small block chevy crate motor thats been sitting a few years.
Playing around on ebay and ran across some small block chevy turbo headers, and some turbos for under $500 bucks.
Im not looking to set the world on fire, but would be cool to put the small block in the boat and make enough power for the boat to haul ass.
Object here is to keep it simple, under budget, and go fast. Not sure whats in the motor, but I know it has a 4 bolt bottom end. Im willing to change out the rod bolts for some ARP's and throw in some forged pistons to help make sure it lives(and make sure the compression is turbo friendly. I was thinking I could go blow through and just run one carb(using one of those Centrifugal hats), but If I need to do a draw through setup thats ok.
How much power can I make and still have this be reliable? Pump gas is a requirement.

[IMPATIENT 1]

500hp otta be safe if the crank is forged, gonna be a cool project, go for it! keep us in pics to;) i've always wanted to build a turbo'd, nitrous fed 433sbc and put it in a race weight cp tunnel:D

[BrendellaJet]

500? Thats not enough to make me want to do it. I was thinking 650 ish would be a good goal...I guess the cubic inches would limit me...

[Budweiser]

I'm not a pro, but I've spent a lot of time investigating on line and reading tech articles on the issue. 500HP would be a boring goal, you could easily achieve that without forced induction (although it would be over 6000RPM). 500 wouldn't be too exciting either. I'd say you're on the right track, 650 to 750 would be easily attainable on pump gas with a 350 small block, granted you have the right parts... Forged crank, rods, pistons, good cylinder heads, intercooler... I'll put up some links later (for info)
-Seth-

[BrendellaJet]

I dont know if the crank is forged, I kind of doubt it but maybe I got lucky. Motor has like 250 miles on it max, so I dont want to take the crank out. Trying to keep this a budget deal. Rods are stock chevy, so I'll upgrade those to some Scats or something similar and new pistons too. Heads will be iron, big valves, need to check the casting #.
Intercoolers look to be cheap. I bet I could find a nice aluminum water to air and run some of the jet water through it to keep the intake air chilled. So far I see $1500 bucks or so to make this happen(if that), just need to find a quality set of turbos thats not gonna fall apart like so many that I've read about from ebay...This might be kinda fun:D

[GAWnCA]

I dont know if the crank is forged, I kind of doubt it but maybe I got lucky. Motor has like 250 miles on it max, so I dont want to take the crank out. Trying to keep this a budget deal. Rods are stock chevy, so I'll upgrade those to some Scats or something similar and new pistons too. Heads will be iron, big valves, need to check the casting #.
Intercoolers look to be cheap. I bet I could find a nice aluminum water to air and run some of the jet water through it to keep the intake air chilled. So far I see $1500 bucks or so to make this happen(if that), just need to find a quality set of turbos thats not gonna fall apart like so many that I've read about from ebay...This might be kinda fun:D
Hey, I'm thinking about doing the same thing. I've got a buddy in Ohio who says by shopping the junk yards (wrecking yards) you can pick turbos at a pretty good price. I've got my eye on a 350 4 bolt motor and a small ski boat. Maybe we can build and compare together. I've got to get my Miller done first.

[IMPATIENT 1]

Hey, I'm thinking about doing the same thing. I've got a buddy in Ohio who says by shopping the junk yards (wrecking yards) you can pick turbos at a pretty good price. I've got my eye on a 350 4 bolt motor and a small ski boat. Maybe we can build and compare together. I've got to get my Miller done first.
look for older 6.5 turbo deisel gm trucks. the turbo on them could easliy be fitted and made to work on a gas motor. pair of them could put out way over 20lbs of boost. the wastegates are attached as well , the inlets are flat enough to easily make header collector plates. i've got a low milage 6.5 turbo i held onto thru the yrs. "just in case":D i know some guys here local that are doin some wild things with turbo'd straight 6's , old school gm and the new gm i-6 motors. had me thinking about a turbo sbc sanger flat bottom project,lol.

[GAWnCA]

look for older 6.5 turbo deisel gm trucks. the turbo on them could easliy be fitted and made to work on a gas motor. pair of them could put out way over 20lbs of boost. the wastegates are attached as well , the inlets are flat enough to easily make header collector plates. i've got a low milage 6.5 turbo i held onto thru the yrs. "just in case":D i know some guys here local that are doin some wild things with turbo'd straight 6's , old school gm and the new gm i-6 motors. had me thinking about a turbo sbc sanger flat bottom project,lol.
I'll bet the whine of the turbos would turn a few heads as they wind up. I'll ask my bud what they are using on their hot rods. He has sent me some photos and some of the plumbing they put into hooking up the turbos, would give a plumber and a muffler shop nightmares!! :D

[GAWnCA]

Bump

[BrendellaJet]

So will it be okay to make this a blow thru setup? I've read its probably better to draw thru the carbs, but this way I only need one. I wonder how much that would limit the power potential in the range I am shooting for???

[GAWnCA]

So will it be okay to make this a blow thru setup? I've read its probably better to draw thru the carbs, but this way I only need one. I wonder how much that would limit the power potential in the range I am shooting for???
Here's a link from buddy Chris sent to me about turbo charging a motor in boats.
http://www.horsepowerconnection.com/CustomersCars/JeffMacy.htm
I think twins would be really cool, though.

[BrendellaJet]

Thats a cool boat. The turbo setup isn't as compact as Im envisioning, but proof of the power potential. He has no intercooler either.

[Unchained]

If you use any OEM turbos you will not be able to go with a draw though setup as the turbos will not have a vacuum seal. The only way you're going to get a turbo with a vacuum seal is from an aftermarket turbo company like Turbonetics.

[Bow Tie Omega]

Then I guess it will be a blow thru. I think it is a cool idea. What if it did work....A real low budget twin turbo small block. It would definetely turn some heads.

[IMPATIENT 1]

If you use any OEM turbos you will not be able to go with a draw though setup as the turbos will not have a vacuum seal. The only way you're going to get a turbo with a vacuum seal is from an aftermarket turbo company like Turbonetics.
mark, do you think the ol 6.5 turbo's would work well on a blow thru box? just curious, still learning turbo set-ups and it'd be a neat project to build a low budget , high boost set-up with some if they'd worked. the turbo's on the 6.5's are garrett with pressured oil, and have oil returns. the exhaust plate would be easy to fab up too. the 1 single turbo makes 14-16lbs of boost on a 6.5l oil burner. the wastegate on it is vaccum actuated but it has a lever so i bet i could find something to control it.

[IMPATIENT 1]

Then I guess it will be a blow thru. I think it is a cool idea. What if it did work....A real low budget twin turbo small block. It would definetely turn some heads.
if ya got the parts, there's plenty of very knowledgeable turbo guys here to help ya set-up. sure be neat man! i would build a short block with hbeams, forged pistons, forged crank before i tried though, turbo's put out big boost.

[Bow Tie Omega]

if ya got the parts, there's plenty of very knowledgeable turbo guys here to help ya set-up. sure be neat man! i would build a short block with hbeams, forged pistons, forged crank before i tried though, turbo's put out big boost.
That kind of takes away from the whole idea of being low budget though. I know for a fact he does not want another $20,000 motor, he aready has one of those in his 21 footer. The small block is going to be for his Brendella. The nice thing about the turbo application, the motor is already under load at RPM by the time the turbos get going. I have been doing some reading as well and there are guys all over the country running twin turbo applications in essentially stock 350 Chevys that have close to 100,000 miles on them that are racing just about every weekend. It all comes down to how aggressive you want to get. Obviously this is a boat application and there are different issues to tend to. But the one thing the car application I referenced above shows, is that the stock engine , with the exception of forged pistons is durable enough to handle a mild twin turbo set up for an extended period of time. It will be interesting to see what happens when he gets a little more aggressive. He is not going to get crazy with the boost, he has already told me that. I do think he wants to get to the 600-650 hp range, and that is not conservative either. If he was to find a nice forged crank though for a kiler deal, he might consider it.
It will be interesting to see what happens, that is for sure.

[BOOGEYMAN]

http://www.horsepowerconnection.com/CustomersCars/JeffMacy.htm
Thats Brian Maceys site, great guy to deal with on turbo parts!!
Want to know what a stock 350 2 blot block with cast pistons, stock rods, cast crank and junk irons heads heads can make??? Follow this link to find out!
http://www.theturboforums.com/smf/index.php?topic=61219.0
Thats my boy Marty's ride and write up, it was also in Car craft this summer. Junk $300 long block with tpi, twin stock turbos of out grand nationals and a sniff of spray. Makes 1,000 hp at the crank and has been alive for 3 years now! Thats about 7,000 street miles countless runs at the track and around 100 dyno pulls.
Its like I always tell everyone...."if you dont rattle it they live for a long time!!"
Travis

[IMPATIENT 1]

very interesting links guys! keep em coming, i'm trying to absorb all this i can, apply it someday.
i've also herd a few guys here on this site that make big hp on essentially stock sbc's. i'm sure it can be done, i just wouldn't personally try in a boat cause a bad day inside the motor could put the boat on the bottom. i've seen motors shoot piston skirts almost thru a stringer, gives me the shivers to think what'd happened it it went down instead of sideways;)

[GAWnCA]

very interesting links guys! keep em coming, i'm trying to absorb all this i can, apply it someday.
i've also herd a few guys here on this site that make big hp on essentially stock sbc's. i'm sure it can be done, i just wouldn't personally try in a boat cause a bad day inside the motor could put the boat on the bottom. i've seen motors shoot piston skirts almost thru a stringer, gives me the shivers to think what'd happened it it went down instead of sideways;)
A bad day inside a motor in anything can be very hazardous to your health no matter what it's in. A front end of a car exploding in your face isn't much fun either. I've seen pistons go through a block in a car and land many yards away. At least in a boat it's all behind you. :D :D :D

[FSTFBDY]

Thats Brian Maceys site, great guy to deal with on turbo parts!!
Want to know what a stock 350 2 blot block with cast pistons, stock rods, cast crank and junk irons heads heads can make??? Follow this link to find out!
http://www.theturboforums.com/smf/index.php?topic=61219.0
Thats my boy Marty's ride and write up, it was also in Car craft this summer. Junk $300 long block with tpi, twin stock turbos of out grand nationals and a sniff of spray. Makes 1,000 hp at the crank and has been alive for 3 years now! Thats about 7,000 street miles countless runs at the track and around 100 dyno pulls.
Its like I always tell everyone...."if you dont rattle it they live for a long time!!"
Travis
Travis,
Funny you just posted that link. I had to register here just to chime in. That is one of the most impressive cars around. Ive been on that site for awhile also. Ive been e-mailing back and forth with GAWnCA on the turbos boat idea and this post came up. He e-mailed me asking some info and I told him to check out that link and to post it here for anybody else who might want to see it.
And then I refresh this post to see if any new info has popped up and low and behold you say just what i was gonna have him post.
You dont need expensive parts unless you plan to spin the thing to 8grand or more. You dont need the best flowing heads/intake for a boosted setup.
If you have to rebuilt or are building a motor at bet put some forged piston in if your on a budget.

[GAWnCA]

Welcome aboard and I hope we can learn from you as well. This is a great bunch who love to learn and teach.

[BOOGEYMAN]

Ya Marty's car and thread on that forum is making its way around the world it seems like!! He makes all that power all un 6,000 rpm as well.
Travis

[FSTFBDY]

Travis,
Reading some of you post I noticed a something wrong.
Marty is Running TE44's not stock GN T3's
Its a 350 Junk yard motor
487x heads, Custom Cam
Aftermarket TPI Base and with Stock Runners (was then how he has AS&M Runners) with a Holly 950 commander for tuning.
Still as said its a stock rods/pistons/crank/block SBC pushing 700+ RWHP with 22psi boost and a 75 shot of giggle juice.
Well worth the 88 pages of ready over on the turbo forums.

[FSTFBDY]

Thanks Greg. I'm sure I'll lurke here more them post. (being in Ohio not much water around except the lakes which I'm not on too much at all.) I miss the FLA beach.
Anyways, Im chime in now and them when I think I can add some info. You got me wanting a little 16ft project hot rod boat now. I have a perfect 350 sitting here ready for a turbo setup have in the corner.

[BOOGEYMAN]

Travis,
Reading some of you post I noticed a something wrong.
Marty is Running TE44's not stock GN T3's
Its a 350 Junk yard motor
487x heads, Custom Cam
Aftermarket TPI Base and with Stock Runners (was then how he has AS&M Runners) with a Holly 950 commander for tuning.
Still as said its a stock rods/pistons/crank/block SBC pushing 700+ RWHP with 22psi boost and a 75 shot of giggle juice.
Well worth the 88 pages of ready over on the turbo forums.
Thats correct he started with the stock gns and then went with the te44's....didnt gain a whole lot with them but yes did make the switch.
Marty has put in his two weeks notice at the dyno shop and opted to go work for himself instead. Wich is perfect because he will be starting my my headers for my jet for the twins in a couple weeks...:)
Travis

[FSTFBDY]

Marty has put in his two weeks notice at the dyno shop and opted to go work for himself instead. Wich is perfect because he will be starting my my headers for my jet for the twins in a couple weeks...:)
Travis
Sweet, Can't wait to see what he comes up with for it. Should be nice.

[Unchained]

mark, do you think the ol 6.5 turbo's would work well on a blow thru box? just curious, still learning turbo set-ups and it'd be a neat project to build a low budget , high boost set-up with some if they'd worked. the turbo's on the 6.5's are garrett with pressured oil, and have oil returns. the exhaust plate would be easy to fab up too. the 1 single turbo makes 14-16lbs of boost on a 6.5l oil burner. the wastegate on it is vaccum actuated but it has a lever so i bet i could find something to control it.
I used to think that precise sizing of the turbo was of the utmost importance.
Then I saw in Turbo & Hi-tech performance mag where they had a GT45 Master Power turbo on a little 4 banger and made 800+ hp with it. I was going to upsize to two GT45's for my 540 CI. That's a huge difference in turbo size to CI of engine, So a way oversize turbo(s) can still work, maybe that's how they get down to that 1:1 back pressure to boost pressure ratio.
I'd say that a couple of turbos from a Pickup truck diesel would be good to try on a gas engine that will turn twice (or more) the rpm.
With the TV77 Garrett turbos I use, one does a big Mack truck diesel and I have two on my gas engine. I would not call them oversize at all. The boost hits like a sledgehammer.
Putting a diesel turbo on a gas engine is going to cause an excess oil pressure problem. I had to restrict the fitting at the turbo to .070 orifice and that may still be too big. They can blow oil through into the compressor housing and then it goes through the motor. I found this out by looking at some photos of the boat running by at WOT.
Look at the smoke coming out of the pipes in this pic,
http://www.***boat.com/image_center/data/500/holeshot3.jpg
Brian Macy has a huge knowledge of turbos and EFI systems.
I've never bought anything from him but talked to him on the phone several times. He was real helpful.
I was skeptical of blow through carb setups but theres no denying the huge power they are getting out of them now. I saw some prices of $ 1200. for a carb that was prepared for that use. That seems excessive to me.
I read that a turbo setup has less mechanical stresses on the rotating assy. than a blower setup putting out the same boost. I believe it is because of the back pressure present during the exhaust stroke. The crank and rods always stay loaded.

[BrendellaJet]

The stock 350 in the T/A on the turbo forums is fockin sick. I just finished going through the first 18 pages and am pumped to make this thing a reality. A fresh motor with good rods & pistons should be doable. I cant believe he is boosting 22 lbs!!!!

[FSTFBDY]

The stock 350 in the T/A on the turbo forums is fockin sick. I just finished going through the first 18 pages and am pumped to make this thing a reality. A fresh motor with good rods & pistons should be doable. I cant believe he is boosting 22 lbs!!!!
uuhuuu, I give that link out alot.
makes me wonder why I spend $ on a callies 3.75 racemaster crank, callies rods and custom made JE turbo pistons. (building a 383 Lt1 for 20psi)
could have saved some $ and got a few junkyard motors to blow up..lol

[BrendellaJet]

What do you guys think about these headers for this build?http://cgi.ebay.com/ebaymotors/Chevy-Short-Small-block-V8-T3-Turbo-Header-Manifold_W0QQcmdZViewItemQQcategoryZ33742QQihZ017Q QitemZ270184298010QQrdZ1QQsspagenameZWDVW
Can anyone recommend a good turbo to use? I prefer to buy off of ebay(something new) Are there any of them there that aren't junk?

[FSTFBDY]

What do you guys think about these headers for this build?http://cgi.ebay.com/ebaymotors/Chevy-Short-Small-block-V8-T3-Turbo-Header-Manifold_W0QQcmdZViewItemQQcategoryZ33742QQihZ017Q QitemZ270184298010QQrdZ1QQsspagenameZWDVW
Can anyone recommend a good turbo to use? I prefer to buy off of ebay(something new) Are there any of them there that aren't junk?
Your gonna get hammered with the "THOSE ARE CHINEESE JUNK" headers stay far away.
Well I'll tell you 1st hand I made a few of my own turbo setups. and got tired of all the people sayin how those are junk because of the import headers cracking etc. So I bought the ones you just linked to right from the manufacture in china.
They are Of nice quality. HEAVY duty feeling and good looking welds. Yes they could have used a larger filler rod for a biger weld but if you make some turbo supports you should have no problem at all.
THEY ARE NOT 304 Stainless as they say on ebay they are 301. but for the price I guess you cant go wrong. If they last a year you got your $ out of them. They just reweld them if they do crack.
Unless you can fab and weld yourself Id say go for it. Same goes for the Ebay turbos.
Id say find Two HOLSET HX40's for HX35's that would easily get your your 600+ HP goal.

[GAWnCA]

Chris, Would they be good enough to get things going and then upgrade to better later on, or is this like a dog chasing its tail?

[BrendellaJet]

Your gonna get hammered with the "THOSE ARE CHINEESE JUNK" headers stay far away.
Well I'll tell you 1st hand I made a few of my own turbo setups. and got tired of all the people sayin how those are junk because of the import headers cracking etc. So I bought the ones you just linked to right from the manufacture in china.
They are Of nice quality. HEAVY duty feeling and good looking welds. Yes they could have used a larger filler rod for a biger weld but if you make some turbo supports you should have no problem at all.
THEY ARE NOT 304 Stainless as they say on ebay they are 301. but for the price I guess you cant go wrong. If they last a year you got your $ out of them. They just reweld them if they do crack.
Unless you can fab and weld yourself Id say go for it. Same goes for the Ebay turbos.
Id say find Two HOLSET HX40's for HX35's that would easily get your your 600+ HP goal.
Yeah, figured they were japcrap, but the pics do look pretty good, and like you said, for the money cant really go wrong. Thanks for the reply.

[Unchained]

http://www.miketurboinc.com/specials.htm
http://www.theturboforums.com/smf/index.php?topic=74174.0

[FSTFBDY]

Id say they would hold up for awhile if you support the turbos off the front of them also. I WOULD NOT just let them hang off the front. ESP in a boat.
Unchained posted 2 good links also. MP70's would be nice. a single S400 would be bad ass.
I need to do more reading up on boat stuff. what predicts the RPM range of a boat? (the sweet spot your at most of the time with a boat) I know its gonna be different then a car.

[BrendellaJet]

Id say they would hold up for awhile if you support the turbos off the front of them also. I WOULD NOT just let them hang off the front. ESP in a boat.
Unchained posted 2 good links also. MP70's would be nice. a single S400 would be bad ass.
I need to do more reading up on boat stuff. what predicts the RPM range of a boat? (the sweet spot your at most of the time with a boat) I know its gonna be different then a car.
In my case, the jet will be the limiting factor in turning rpms. To give you an idea, my 548 Chevy makes 800 NA HP @ 6000 rpm, and I can turn my A impeller(considered a big impeller, a B is smaller, C smaller yet, AA is the biggest) 5800 RPM...With the turbo deal I hope to be able to turn 5300 on a B impeller or thereabouts.
In other boats there are gears and propellers that will determine RPM.

[FSTFBDY]

So you want to swap to a smaller impeller? I'll guess smaller is better? less rotational mass?? more velocity?? Again Im a total newb to HOW/what works with boats. I understand the jet/impeller concept. Just dont know how the jet is the factor in rpms.
So say I used my 383 LT1 with large single turbo and the motor spins to 6800 RPM the JET would still be the limiting factor is say reving past 5300 rpm?

[Bow Tie Omega]

So you want to swap to a smaller impeller? I'll guess smaller is better? less rotational mass?? more velocity?? Again Im a total newb to HOW/what works with boats. I understand the jet/impeller concept. Just dont know how the jet is the factor in rpms.
So say I used my 383 LT1 with large single turbo and the motor spins to 6800 RPM the JET would still be the limiting factor is say reving past 5300 rpm?
The jet is the transmission/rear end so to speak, it is the load placed on the motor. Changing an impeller is like changing rear end gears. Each is going to have a different effect on the motor. That is about as simple as I can explain it. I hope that helps

[FSTFBDY]

I figured it was kinda something like that. any good links to read more on it.
:idea: mmm, that makes a few more questions pop in my head but I don't want to hijack this thread so Im off to hit the search button.

[BrendellaJet]

You can change impellers, or trim one if its too big. Or just throw more boost at it until you reach the desired RPM.
When trimming impellers, you decrease the amount of thrust the impeller can generate, but also decrease its mass, allowing more R's.
Now, where to find some cheap, but quality turbos? Part of this project was to be budget oriented. Spending $500 on each turbo is more than I want to spend, especially considering the motor wont receive a lot of attention. It is fresh and will get forged pistons & and maybe a nice set of rods, and a new cam:D but those can be had for pretty cheap. I may have to rethink and spend the coin to get a quality set of turbos unless someone has an idea on where to get some for a good price. It looks like the ebay deals are pretty hit or miss. Its the "miss" part that has me worried. I have a paddle in the boat, but I dont want to have to use it.
My wife is going to kill me if this turns into another project.

[GAWnCA]

My wife is going to kill me if this turns into another project.
Just buy her a new toy that will keep her busy! :D :D :D

[Bow Tie Omega]

Just buy her a new toy that will keep her busy! :D :D :D
COACH:D...Oh shiot, never mind, one of those bags is as much as a turbo

[v-drive]

You can change impellers, or trim one if its too big. Or just throw more boost at it until you reach the desired RPM.
When trimming impellers, you decrease the amount of thrust the impeller can generate, but also decrease its mass, allowing more R's.
Now, where to find some cheap, but quality turbos? Part of this project was to be budget oriented. Spending $500 on each turbo is more than I want to spend, especially considering the motor wont receive a lot of attention. It is fresh and will get forged pistons & and maybe a nice set of rods, and a new cam:D but those can be had for pretty cheap. I may have to rethink and spend the coin to get a quality set of turbos unless someone has an idea on where to get some for a good price. It looks like the ebay deals are pretty hit or miss. Its the "miss" part that has me worried. I have a paddle in the boat, but I dont want to have to use it.My wife is going to kill me if this turns into another project.
Your wife wouldn't say a word to you about it. She would however put it in her memory bank and use it at a later date. Very smart woman. Now get this thing movin. pop

[ck7684]

I was gonna add twin turbos to my '84 vette...had the crossfire injection engine...was gonna piece the setup together from a couple turbos from the chrysler 2.2 turbo motors and other assorted production car parts...never got off the ground though...

[GAWnCA]

I was gonna add twin turbos to my '84 vette...had the crossfire injection engine...was gonna piece the setup together from a couple turbos from the chrysler 2.2 turbo motors and other assorted production car parts...never got off the ground though...
So CK, do you still have the turbos? Where did you get the turbos and at what cost?