3.4 twin charged

I didn't read everything.

Fic6 is good. Ran straight Sc, twin charged and now just turbo on it.

Just got a Fic 8. Has a boost controller, and more logging capabilities.

I would honestly say just go turbo. If 3.4 liter, Gt3582r with .82 housing. Fmic, 3" exhaust and 440cc injectors with Aem 340 pump. Amazing.

 

If you want my fic6 I'm willing to sell it after I get my 8 ironed out.

 

What was twincharged like?

 

Very responsive. 13psi at about 1200 rpm wot. Burn out city. Useless in sand, very embarrassing. Just digs holes in 4x4. Choked out up top, even with SC bypass open.
It would need a built engine and a gt4294 turbo with e85/high octane to thrive.
Honestly just pick one or the other. Save the money and headache.
Sc bolts on so easy.
Turbo is more intricate, but will make more power overall.
Be realistic with your wants and needs, especially in this economy.

 

Wouldn't the gt4294 be inefficient if compounding at all times? say ratio of 2 is being used (total of ~25 psi if sc is 7lb)

How much #/min of air would the 3.4 run at say 18 or 25 psi of boost?

Also when always compounding, the sc cant restrict, so was the intake being the restriction that choked the engine or the wastegate?

 

@Torspd !!

 

You could probably run a larger turbo even. I ran a gt4202r and a built ct15b on my compound 1jz vvti. 40psi total on e85. Very braud power band, but it really needed to go to 50 or 60 to really get into the efficiency range. More than the map sensor and stock engine could handle. Got bored and sold it to get into trucks.

The SC basically turns the 3.4 into a 5 liter. It was spooling my 35r way too quick even with the largest exhaust housing. Going with a larger turbo would spread the power band out and make it more usable. You would want a turbo that can move alot of air at a low psi to keep the compound psi down. With a built engine you could run more psi, I'm still on a stock engine so 13 was has high as I went.
Another problem with our roots type SC is there is no intercooler. This could be combated with meth or e85, but that's just one more thing to run out of. Being a off road rig e85 doesn't make sense simply for mpgs and availability. A dedicated city or strip vehicle could take advantage here.

 

IU=ll be selling a 3.4 sc here soon why not do two super chargers! hahhaha

in all seriousness im interested to see what comes of it!

 

that set-up brings tears to me eyes ... man....!

 

From what I saw, F1 cars would run small boost through small turbos. Small exhaust housings and giant intake housings. They just used gigantic east gates so that when they hit high rpm it didn’t restrict airflow.

Highest I’ve heard of someone running consistently is now the 20 psi. Was 18 on customtacos. I was also looking at the bottom of our 2nd gen housings and wondering if we could put a water to air inter cooler in there? Looking from the bottom and sliding one in like an air filter where it is square? Would need a broken housing for a donor for this

 

Also because of the supercharger, it doesn’t completely act like a 5l. It has less back pressure than boost and that affects cam overlap. On twincharged it’s probably best to run a cam for supercharging because of the larger boost than back pressure is closer to running sc’d.

 

Cutting into the supercharger here:


And sliding in a water to air intercooler. Though I dont know if the manifold after it would be sufficiently large to even the pressure to the cylinders.

I imagine it kinda like the 4.0 SC, it would almost look like sliding in an air filter with water hoses attached and bolting it on

Also: what angle would be best? angled with more volume after the cooler or with the runners to the cylinders immediately after? Or somewhere in between?

 

Also need to remember that cams are cams. All cams are boost cams. All adding boost does to a cam, is increase the torque throughout the rev range. Boost should not affect the shape of the curve. Check Richard Holdener's youtube channel - it's quite fascinating https://www.youtube.com/channel/UC8uf_zVTV63l1-uRSx6XbnQ

 

my point was that valve overlap on a supercharging cam will be larger to allow all of the exhaust to leave and keep the cylinder cool. Also more duration and less lift? A cam for a turbo should have less valve overlap because the back pressure is typically more than the boost made into the intake. I only say this as we can’t change overlap on our cams because it’s together by the gear in the center, not belt driven on the outside. (Custom cam to do so?) at that point it’s probably on a forged bottom end and doing 30+ psi

 

overlap is a great idea for keeping exhaust flow high to help with turbo spool, but im wondering if it's precisely necessary with a twin charged setup

 

It would be better. At some point our cams are definitely choking the engine

 

This is an engine with a low potential for HP though without a significant portion of bottom end work and almost zero aftermarket support for power parts, I think you'd go down a unique and expensive road doing much more than boost and a tune. Can't really even fine degree the exhaust cams or intake cams on this engine.

 

It would be some very custom cams if you converted to belt driven for both, exhaust cam would be turning the other way. And yes, a very custom road. Custom girdle as well I would think, custom arp rod bolts and custom rods and perhaps pistons, 7.0:1 pistons? Custom arp head studs in the stronger metal they use. At that point, would it be worth designing a set of custom heads?

 

holy shit thats low compression I'd think 9.0:1 would be fine given the quench design of the head haha. Electronics and knock mitigation have come a long way since the late 80s and early 90s, we don't have to rely on crazy low compression for boost safety anymore, which is good cause no one wants a torqueless truck engine that has trouble spooling its turbo. Shoot my BMW somehow gets away with 10.2:1 compression and 21psi.

 

Yeah was just thinking very low and going for stupid hp and putting the engine into something else, like a kit car and making 1200hp. Though that low is probably too much. We have 9.6:1 as it is, yeah?