Boosted slant?

-
Killer6 said:
I've watched SS 396 Chevelles run a 16 flat in the qtr., same as My "Killer6"......
Click to expand...
That would be some hurt feelins to get outrun by a slant 6 in a big block Chevelle. lol
 
RustyRatRod said:
That would be some hurt feelins to get outrun by a slant 6 in a big block Chevelle. lol
Click to expand...
My buddy had a '75(?) NOVA 4bbl/4spd/350, won the Street-class bracket championship that year at Keystone, beat Him 3 out of 3 on Hunter stretch one nite, getting that car moving on a cool country road at night ain't the same as a clean & prepped track....lololol!!
 
Jim_1975_.jpg

That one....
 
Jonnylightening said:
I was under the assumption that all 2bbl slant intakes were super six??. Either way shooting for 3-350hp at around 10-12psi. More is always better though!
Click to expand...
That boost level is gonna take E85/Water-Meth inj./Intercooler, one of those 3, 7-8psi is pushing it w/o any of those. There's a big difference in 300 & 350hp, boost can get You there sure enough, but the piston that lives @7psi may not @12psi for sure. You can look at what the PowerNation mill did, but it ain't a cheapo build, so what are You in for$$$$?
 
Killer6 said:
That boost level is gonna take E85/Water-Meth inj./Intercooler, one of those 3, 7-8psi is pushing it w/o any of those. There's a big difference in 300 & 350hp, boost can get You there sure enough, but the piston that lives @7psi may not @12psi for sure. You can look at what the PowerNation mill did, but it ain't a cheapo build, so what are You in for$$$$?
Click to expand...
I wouldn't think those boost levels would be pushing it for a slant with stock compression. They normally blueprint down in the 7s. Perfect for forced induction.
 
MadScientistMat said:
Many of the aluminum slant six manifolds had leakage issues, although if it doesn't leak under vacuum, it won't leak under boost.

Cast iron super six manifolds will not have leakage issues, but welding port injector bungs if you go EFI would be a challenge. I also would be concerned with a TBI about fuel distribution issues, although it may work. It may also be possible to prep a BBD (or two barrel Holley, probably more info about those) for blow through use.
Click to expand...
Yeah, I'd never use the factory 2pc. Super6 intake, iron or DC/MP cast Al-U-minimum only. Welding bungs in an iron intake isn't needed, they can be brazed in, or drilled & tapped for threaded bungs....OP is planning on Sniper(TBI), so moot at the moment..
 
Killer6 said:
Yeah, I'd never use the factory 2pc. Super6 intake......
Click to expand...
Why? Most of the defective ones have been out of the system for a long time. There was a TSB on them I believe and most got replaced. I have one that had I pressure tested that's excellent. I like them. They are light as a feather.
 
RustyRatRod said:
That would be some hurt feelins to get outrun by a slant 6 in a big block Chevelle. lol
Click to expand...
A few years ago I went to a "street legal" night at Gainesville Raceway. First run was heads up against a 61 full size Chevy with a 350 and B&M blower (beautiful car). My car was a 66 Barracuda, with a 170 slant six. I had him at the 1/8 mile, and he got me by about a 1/2 fender at the 1/4. He couldn't believe all I had was a 170 slant six (on spray). Went a 12.905 at 101.85 mph. At 3250 lbs and thru mufflers.
 
RustyRatRod said:
Why? Most of the defective ones have been out of the system for a long time. There was a TSB on them I believe and most got replaced. I have one that had I pressure tested that's excellent. I like them. They are light as a feather.
Click to expand...
Because I can't tell the difference between one that was replaced under warranty and one that wasn't just by looking at it, and having worked at a few dealerships, many folks don't get their car serviced there & ignore snail-mail, e-mail, & even messages on the freakin' dashboard that there is a recall/campaign that is safety related.
Some folks just drive, I'm betting there are tons of Tecata airbags ready to frag an unsuspecting passenger right now, even tho' it's been all over the news & a major story for several years.
I like 'em too, but the thought of a pressurized backfire splitting one in two or whatever doesn't appeal to Me, for the 15.5lbs it saves over the iron one I just wouldn't w/o a high-pressure test or just re-welded w/a TIG.
Then there's the carb base, it has a big scallop between the mounting holes on the valve cover side, actually slightly undercutting the BBD gasket shape, I had to epoxy fill&file that in just to put the bigger 2245 Holley on the K6.
Just food for thought, in both the iron & 2pc Al I opened the base to an oval.
 
Charrlie_S said:
A few years ago I went to a "street legal" night at Gainesville Raceway. First run was heads up against a 61 full size Chevy with a 350 and B&M blower (beautiful car). My car was a 66 Barracuda, with a 170 slant six. I had him at the 1/8 mile, and he got me by about a 1/2 fender at the 1/4. He couldn't believe all I had was a 170 slant six (on spray). Went a 12.905 at 101.85 mph. At 3250 lbs and thru mufflers.
Click to expand...
Now that's a cool story!
 
I will say 5-7psi really wakes a slant up! I will also say so far mine has had No issues with that level and more ( on a fairly safe tune ). Even with .120 off the block, Stock pistons with some new rings and bearings. I wanted to put it together on the cheap before spending the money on fancy pistons or anything else. No methanol just a water to air intercooler. I have no doubt this thing would live a long life at 5-7psi maybe even a little more. unfortunately I will be building another short block sooner than wanted. this block has a crack in the water jacket and all the JB weld and sealer doesn't seem to want to hold anymore. I will also add I should have done this 15 years ago! when I first started collecting the parts to do it and was talked out of it.
 
Can that crack in the block be blam d on the turbo?
 
You say that you're running an intercooler, so can I assume you are running blow thru and not draw thru? I'm planning at least initially to get it running on a 318 BBD carb so I was looking to start out with draw thru. 5-7 psi was about what I had in mind. Are you running a stock cam? I had mine reground, Oregon cams took care of what I was after, but I hope the cam I picked will be alright with boost. I know it has no overlap, otherwise it's what would have been considered an "rv cam" back in the 80s-90s, you don't hear cams called that anymore. It definitely isn't anything radical.
I want to run the BBD that I have if possible because it's an nos carb that I bought a couple of years ago, and only has a couple of hours on it since I took it out of the box. Genuine NOS, not chinesium.
 
NoCar340 said:
Not all 2V Slants were necessarily branded as Super Sixes, but they're virtually identical other than the manifold material. My '78 ex-USAF D200 4-door had a cast-iron 2V manifold but no "Super" designation on it. Everything interchanged with Super Six Volare parts, so to me it was a Super Six. There wasn't much super about it in a 6,500lb truck, though.

The limiting factor won't be the intake manifold, it'll be the cylinder head, especially on a Slant larger than a 170. Oversized valves and porting are time and money well spent, particularly with forced induction. Intake manifold (boost) pressure is a measure of the resistance to airflow. In other words, the PSI reading is simply telling you how much air is not moving through the engine. You'll flow more with a ported/valved head and 12PSI than you will with 15PSI and a 100% stock casting. More air through the engine = more fuel burned = more power. It's no different than natural aspiration, really, except now there's pressure at the valve when it opens rather than a vacuum being generated by piston movement.

Similarly, on the exhaust side, the factory manifold will not be the major restriction--it'll be the turbo. The lower the backpressure after the turbo--the exhaust system--the greater the pressure differential across the turbine wheel. Less pressure after the turbine = quicker spool times/less lag. There is no such thing as "good" exhaust backpressure with a turbocharger.

Just like water, electricity, and human nature, any resistance is exacerbated by increased pressure. This is true on both the intake and exhaust sides.

"Street Turbocharging" by Mark Warner is an excellent resource on this subject. It might not be as entertaining as reading internet forums, but the advice is consistent and solid instead of conflicting opinions. It's well worth the price and a couple of full read-throughs to fully digest it. There's a heck of a lot more to forced induction than just hangin' a turbo on the engine and calling it a day (especially regarding ignition timing). Learning the hard way is a lot more expensive than a book and a few nights' worth of reading.
Click to expand...
Excellent post.
@Jonnylightening whatever the intake does na it will do with boost, just more of it. If it’s got longer runners, it will make more torque both na and on boost than one that doesn’t. If it’s got short runners it will make more up top than one that’s longer.
 
block was cracked before boost was added. I missed it when the block was cleaned and milled ( should have saw it ) think it froze at some point.

I have multiport fuel injection on it. i knew I could control each cylinders injector that way.
it has a cam, probably more duration than ideal but it is working pretty good. 465 lift 220 [email protected]
 
Don't know the numbers of the cam I have in mine duration wise off the top of my head, have the sheet in the house by the desktop computer
All I know of hand is I have a Oregon cams 819 in there right now. I hope if I decided to go thru with the turbo it'll work. I remember when I was building this engine (long thread both on here and the /6 forum from about 2 years ago) people were saying I should use one with a different lobe sep angle (wider) than an but I'm hoping that for my purposes what I have now will suffice.
Just curious where your block is cracked.
I built a 63 /6 about 30 years ago and only found out it's block was cracked horizontally, a little above the oil pan rail and right behind the PS pump a crack about 3" long. Had no idea until it was all back together and running again. Then it started to seep when engine was hot and radiator was under pressure. I wasn't happy. But that was also the car that I totalled 700 miles after I put that engine into.
I wound up pulling the head and putting it onto my dad's car and the freshly rebuilt (albeit cracked) short block went to the junkyard with the crinkled body
 
I'm not completely sure I'm gonna add a turbo to my current/6 project, or not, yet. It's just an idea I'm toying with in my head at this point. It runs as is, I'm onto bodywork at the moment, and if I do decide to add the turbo it'll be after I rack some miles onto it as is for now.
 
A turbo will multiply the NA power of all cams, will a wider LSA make more power over narrow possibility is it gonna be huge difference probably not.
 
You must log in or register to reply here.
-

Back
Top