How can you tell which you have? I have a custom build engine...is there something to look for on the engine itself that will tell you?
thanks!
thanks!
4 bolt vs 2 bolt main
- Thread starter 98stangv8
- Start date
technically iron are 4 bolt main, and aluminum are 6 bolt main. the cross bolts are main bolts.
ok...with that, maybe you can help some. I am in the process of getting a Vortech V2, SQ installed...I have a 302 stroker with forged internals, Kellogg Crank...and the owner asked me how many bolt main I had.....I want to run approx 10-12 lbs of boost...he said that may be too much with a "2 bolt main"
any thoughts?
Thanks!
any thoughts?
Thanks!
CobraRed_96_GT
Active Member
He's talking about the main bolts you'd use studs for. Ours have two main bolts and 2 side bolts. You have 2 main bolts. But the side bolts are what go first not the mains if im not mistaken.
My thoughts are that he has no idea what he's talking about. His still got 302 OHV on his brain, not Modular OHC. I've seen guys run into the 600hp range with the stock nodular iron crank and 2V GT block and others running well into the 600-900hp range with the forged crank and 2V GT block, so that should be the least of your worries. The rods and pistons will go long before the crank or block does. The 6-bold mains are nice if you're going to be running a lot of sustained RPM, but for most applications, they're overkill.
98COBRA281
10 Year Member
10-12 lbs is fine on a stock bottom end, with a forged motor, you could prolly run up to about 700+hp
+1 on the guy thinking its a 302 pushrod motor.....
twogts4us
15 Year Member
Wait, the shop owner who is installing this SC for you doesn't know about mod motors? No offense, but why on earth did you pick him to do your install?
The 4.6L mod motor (ALL of em) have cross bolted main caps.
The 4.6L mod motor (ALL of em) have cross bolted main caps.
find another engine builder, he thinks you have a 5.0 ohv engine. Stock SOHC 2v engines have 4 bolt main and the DOHC 4v blocks have 6 bolts.
Thanks guys...this was a schmuck that worked there...not the owner...the owner is legit...this guy I guess just didn't have a clue..
Ok...to further the question...since you guys aced this questions..
I know this has been asked over with a stock engine..but with the forged internals on my build...how many pounds of boost would you say are safe to run with the Vortech?
How many pounds can I go until I have to upgrade the rib pulley system?
Thanks!
Ok...to further the question...since you guys aced this questions..
I know this has been asked over with a stock engine..but with the forged internals on my build...how many pounds of boost would you say are safe to run with the Vortech?
How many pounds can I go until I have to upgrade the rib pulley system?
Thanks!
CobraRed_96_GT
Active Member
I don't quite know the specs. Have they been posted? Cobra crank? ARP main studs? Stock side main bolts? ARP headstuds? What type of pistons? Dish?
It's not an issue of PSI. Cuz one guy making 12psi with ported heads/LT's/blower cams will surely make more power in most cases than the guy with 14-15psi stock heads and manifolds. PSI is a measure of resistance, not flow.
Compression is the deciding factor of how much power you'll be able to run on pump gas, or how much you'll need to pull timing. Generally a forged shortblock should have no problems supporting a 6 rib kit vortech. But theirs random factors like getting any detonation on mahle 4032 grade pistons where it doesnt take much power to break.
The amount of "boost" you'll be able to run will depend on the quality of your fuel and your ability to keep your air charge temperatures cool.
With 91-octane in your tank and no after cooling you'll probably be limited to 10-12psi.
Add race gas, water methanol injection, and/or an A/A or A/W intercooler and you'll be able to push it a lot harder without pulling so much timing.
Remember....boost figures should be used as a rough reference only. Airflow is what you're after. Boost is a measure of restriction on the intake side. A car seeing a lot of boost on the gauge may not necessarily be seeing a lot of airflow. Port and polish your heads and open up your intake and exhaust system and your "boost" pressure will drop, but your power levels will go up.
As far as pulley conversion....don't quote me on this, but I'm under the impression that guys are swapping out to 8-rib pulleys at about a 3.20" blower pulley. There are ways around it though. Increasing the diameter of your crankshaft pulley will also spin your blower faster (increasing boost) while allowing you to stick with the 6-rib configuration.
Realistically though, most guys even with forged internals don't push things much past the 425-475hp range with the S-Trim.....especially with a street car. That seems to be the limit of their designed efficiency range and you've also started reaching the limit of your stock fuel system. I've seen one example push it as high as 650hp on a fairly wild engine combination, but at that point you're running the blower waaaay out of its efficiency range, and shortening its lifespan dramatically. Not to mention you’re going to require an extensive and expensive revamp of your fuel and ignition system.
Thanks guys...here are the specs right now:
9.8:1 compression
9cc dished pistons
Manley rods/pistons, Kellogg Crank
VT stage 2 heads , p&p
PI intake
ARP studs
custom grind conservative cam...was ground for a possible blower later from MPH
I think I got it all in there...does that provide any new insight over what gearbanger stated?
At what point do you have to upgrade exhaust to 3" pipes? What power levels?
Thanks for the help!
9.8:1 compression
9cc dished pistons
Manley rods/pistons, Kellogg Crank
VT stage 2 heads , p&p
PI intake
ARP studs
custom grind conservative cam...was ground for a possible blower later from MPH
I think I got it all in there...does that provide any new insight over what gearbanger stated?
At what point do you have to upgrade exhaust to 3" pipes? What power levels?
Thanks for the help!
CobraRed_96_GT
Active Member
+1. Fuel system and type of fuel. I'd recommend some race gas added to 91 13psi and over on 9.8:1. May need a SCT BIg Air from pegging out a LMAF 90mm around 450-475rwhp.
If it was me and I didn't want to buy all that stuff I'd stop at when the 90mm maxed. That way you could still use a S-trim, maybe a single focus pump for cheap and a cheap MAF. Otherwise I'd say buy a T-trim or Novi 2k and actually build some power. You'll need to be pulling timing and running more octane than most to hit high boost - although 9.8:1 isn't too hard to work with.
cool...thanks for the great info...I am just looking to keep this on and use it for a long time...didn't want to put too much into the motor and ruin it..
Could I go with a single focus pump now, or would I need to run a dual setup?
Will a single pump push enough for 400+rwhp?
Thanks!
How about exhaust...when you do need to go up to 3" pipes?
