I built this motor last year, 1995 lightning 351w, with the pistons that came with it,,the motor was a multy port fuel injection, ,,,that i did not get,,,so i put a edelbrock manifold with a 700dp on it,,,,turns out its only got 8 to 1 compression,or less,,,,runs fine up to about 4200 rpm, 43 mph,,,out of the hole is great, but no top end...i found a new t5 turbo , and a throtle body fuel injection kit,,in the garage,,,and thought it might solve my problems
any thoughts, or pics would be great

allso noted that some turbo builds have the fuel system before the turbo, and some after the turbo. What is the differance

cam is a comp cam
35-242-3
grind fw xe268h-10
valve lift .510 .512
duration @ .050 224 231
lobe sep 110

will that work

16ft sidewinder jet boat

thanks for any input

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depending on what you turbine you go with , a bigger turbine you can get away with a smaller lobe separation(like what you have) , small turbine you will want to go with a 114 to avoid reversion

what are the big and small measurements of the compressor and turbine wheels??

as far as fuel I think your talking about draw though and blow though

if going blow though you will want to find a single plane intake

some guys have made eddy carbs work for blow through but most use a holley double pumper

 

Close to 68 and 58mm ,,,,,the # on the turbo are,,,j84,,,,then on the inside of the intake side,,,5327-579, 5615, k27-015, hj,,,,if you know what that means,,,,,I just googled these #'s......is this a cheap china knock-off,,,,should i use it???? Or should i go back to plan [a] and take the MOTOR APART and put the proper pistons in??? {flat top} to build up the compression, and forget the turbo,,,as per thread#1

THE HOLE REASON FOR THE TURBO THOUGHT, IS THAT I PUT THE LOW COMPRESSION PISTONS IN MOTOR, THAT CAME WITH IT,,,,NOT THINKING,,,,,NOW THERES NO TOP END

I WOULD REALLY LIKE TO TURBO THIS BOAT, JUST BECAUSE OF THE COOLNESS OF IT,,,BUT IF THIS TURBO IS GOING TO F-UP ,,IT COULD THROW PARTS INTO MY INTAKE,,,THAT WOULD NOT BE NICE

i have a torker 2 manifold
i have both eddy and a holley 700 dp
have a carb hat
EVEN HAVE A FORD Y PIPE

 

My first impression is there is something else not right...... What was the original powerplant, and how did it perform with it? A compression bump will give you more hp, and work better with your cam, but typically its only like 2% per point of compression. The engine runs like it should? Good compression? Was the cam degreed when installed?

 

so the 68/58 is the compressor??

you could get a gt45 that would work ok on that engine for about 300.00 new online

or if you have a little to spend id go with a something that had a 75mm compressor inducer

 

ok cool,,,the motor idles great, reves right up, 5500rpm for 1/4 sec,,, sounds great,,,but under pressure or in the water,,i only get 4200rpm,,,,this is a used motor that i had machined to 30 over, crank too,,new bearings and piston rings,,,,pistons came with the motor are deep dish, 10cc, the cam was put in straight up,,,no advance or retard,,,electrical timming 34deg total

at 4100rpm, the throttle is a little more then half,,only the two barrles,, 4 barrles or full open only gives 200 more rpm
I THINK ITS THE LACK OF COMPRESSION

 

Have you VERIFIED TDC on the balancer? And the marks on the timing gears? Sure sounds like retarded timing, either cam or ignition.

 

Thanks rick
i think you may be right. there is something that is not right in there..
by "timing gears" do you mean timing chain marks...
i'm going to pull the motor this spring...
after some reserch, i found the turbo that i have here, is a chinese knock off..5 out of 10 dont make it past 100 hours,,,
i don't want that going through my motor..
while the motor is out, i want to ......full wet and dry compression test,,,cc the combustion chamber, that i think is over 100cc's,,,and get that down to about 70cc's with some new flat top pistons..
the 100cc's means about 7-1 compression,,70cc's will bring it up to about 9.6-1cr
but this is what i have now...

bore 4.030
stroke 3.5
head vol. 60cc c90e heads
piston dish -10cc
piston to deck 0.041
gasket 0.035??

that works out to about 9.5-1 compression,,,,,am i right...that should be just about perfect for 91 octane
by the way,,,this is in a jet boat,,,so its like a 3000rpm stall converter
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the timing chain gear on the crank, can go on three differant ways....circle, square, dimond,,i put it at the circle, which i thought is straight up,,,the others are 6 deg advance and retarded...

 

I've seen this happen before is why I'm asking, did you line up the CORRECT mark (for the circle) with the upper gear? 7:1 compression? A 76 or 80 mm GT45 or a pair of GT35s would wake that baby RIGHT UP!!!

 

http://www.summitracing.com/expertadviceandnews/calcsandtools/compression-calculator

I have you figured at about 9.5:1 compression using the above numbers

 

found these pics from my build
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I'm back,,,,got the motor out. And did the compression test while the motor was hanging on the chain,,,,,,all below 100 psi,,wet and dry,,,so i tried a differant compression gauge,,,same thing,,,all below 100 psi,,wet and dry,,,,
so next i cc'ed the combustion chamber,,,plugs out, #1 tdc, motor tillted, plug hole up top,,,,102cc's,,,,,too much,,,,i was hoppin for 70
but this all sound good for a turbo,,,,can someone school me on blow and draw,,,i know its after and before, but what are the draw backs of each,,,or bonasess? Of each,,,,again i have a hatt, t5 turbo, and a bunch of exhaust piping,,,,THANKS FOR YOUR KNOWLEDGE

 

Blow-through is really the only way to go...

 

please explain why?????
i'm tring to learn it all

 

You don't need a huge carb to supply enough fuel/air to support a lot of horsepower, a 650~750 is enough to supply well over 1000 hp in blow-thru configuration, it would take at least a Dominator as a draw-thru. For most applications, it takes special seals to cope with fuel going through the turbo. On top of that, blow-thru is MUCH easier to package,

 

ok cool,, what size pipe should i use from exhaust manifold to turbo,,,and do i have to use a intercooler?????
yesterday i pulled the timing chain cover, and found a worn out chain,,,over half inch play,,,i'll replace that too

 

That means your cam timing was retarded, moving the power band upward, probably up past where that jet drive would let your little motor spin, most of those boats had big blocks,

 

k,,thanks rick,,,i will think some more on this,,,and let you know as i go

 

so i got a new timimg set,,,,man is it nice and tight,,, so if it put the timing chain on in the 4deg advance,,,would that bring the power band down lower,,,more useable range
today i'm figuring out a DIY leak down tester