Finally finished

[AaronGTR]

That's cool. I'll have to pick up a can and try it. And I didn't say you were disagreeing with me. I just wanted to point that out for anyone's benefit was all.

[SofaKingWeToddDid]

you dont need to weld it with a MIG. JBWeld is sufficient for any cause.

[Joseph Upson]

A finely tuned wire speed for your welding power setting will not create much spatter to clean up, just a nice harmonious phiz as the steel is being laid down under shielding gas. I have used the anti-spatter stuff before but it was only necessary with the flux cored wire I was told by a pro to use when welding on cast iron, it worked very well.

What's with all the "metal sphagetti" Midnight, looks good but the shortest distance between two points with good contours is best between the cylinder heads and the turbo. You're just showing off. Nice work.

What kind of turbo are you using? 60-1

[IsaacHayes]

I wonder too about the headers going into a turbo. Most say won't help since the turbo is a restriction... Perhaps at high RPM you have momentum from the turbo spinning and exhaust going that there isn't TOO bad of a restriction and there might actually be some savaging going on near the collector...

[MidnightriderZ24]

haha, joseph, kinda true. kinda for show, but 7500 rpm's they should flow damn good. the turbo is a holset hx40 "pro wheeled", it has a billet 62mm compressor wheel. 16cm exhaust housing. ive seen dsm's making 650 awhp++ on these. my goal is around 500-550 whp.

[AaronGTR]

I think it depends on your boost level. I've heard decently sized log manifolds will work for most turbo setups and moderate boost levels. I've also heard though that for higher boost headers which flow better will make more power than logs. More boost=more exhaust coming out. I've also heard header style mani's, especially if they have equal length primaries, help properly time the exhaust pulses to spool the turbine faster. Of course, that's pretty hard to design in a sideways mounted fwd v6 engine bay.

[MidnightriderZ24]

which is why my rear header isnt as complicated. the front header is longer due to the fact that the crossover pipe coming off it is shorter, compared to the rear header. either way it looks sweet. itll look sweet ceramic coated too!

[Joseph Upson]

Headers should be used no doubt, I just wasn't expecting to see so much tubing, are you ADHD :-). Glad to see someone is making progress. It will be a few more months before I can get back to mine. I'm aiming for about the same power level and will be switching from a twin setup to a single turbo for more simplicity and dependability because once I'm miles away from home I can't afford a break down. I'm also upping the compression ratio to about 11:1 given how knock resistant it is on mid grade fuel without the water meth injection installed (slight knock at 8psi in a very lean spot). I'm trying to achieve high efficiency and power for hopefully well over 30 mpg with the 6 speed.

What size turbine A/R are you running? and what are you using for engine management? Code59 has been worked out for DIS ignition finally.


I came up with a T72 followed by a T70 as the best efficiency compressor for the 3.9L and about 1.32 for the turbine A/R. I considered chevy rods but I've read a lot of positive things about the stock powder medal rods and didn't want to break the bank since switching to them would add ~$800 in rods, machining and offset grinding the crank to add the .110 increase in stroke to put the piston back within .010" of the stock location. Currently I'm looking at about $350 for balancing with the LS1 pistons and installing .927 wrist pin bushings, plus the planned upgrade parts from W-T, head studs, etc..

[IsaacHayes]

I'd leave compression alone if it does good where it's at, that way you don't have to run premium all the time with boost, or meth. We can only get 91 here. Is there an LS1 piston that keeps stock compression on the 3900 but forged?

[Joseph Upson]

I'd leave compression alone if it does good where it's at, that way you don't have to run premium all the time with boost, or meth. We can only get 91 here. Is there an LS1 piston that keeps stock compression on the 3900 but forged?

I'm running mid grade mix at about 90 octane maybe so with proper tuning I still have room for compression increase without having to run premium. I'm running the mix as a precautionary measure until its tuned. I barely got 1 deg of knock retard at 8 psi in an extreme lean point on the fuel map so there is room for an increase. I guess the cylinder head design, oil squirters and intercooler are really doing their job. I also try to keep engine temps below 190 deg.

My LS1 pistons are forged and most of the aftermarket is forged. I saw several different options and there were some that were very close to stock, however the ones I purchased were the best deal at less than $400 shipped complete with rings. They are the same diameter as stock but 9 cc instead of 18 cc dish. Don't want to clog up Midnights thread with my madness so I'll stop now.

[MidnightriderZ24]

no adhd, not that i know of....ha. exhaust size is comparable to a 1.10 a/r. but the turbine is designed for slow cold diesel exhaust. in reality its prob around a .82 a/r. i didnt know anyone got the code59 figured out, news to me. i was planning on running megasquirt 2, but if this code is working i might look into that. for fuel i plan on using e85, due to its EVERYWHERE here in wisconsin!

[gectek]

wanna go ride bikes?

[3400-95-Modified]

You should change the title to this topic....

because you know as well as I do, its never finished

[MidnightriderZ24]

You should change the title to this topic....

because you know as well as I do, its never finished

this is true. very true.

[torq455]

finished is a relative term...meaning you are finished with the project that you started, and got it working. refinement is another thing.