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So what are the street/trail results? There are all kinds of german "sport luxury" cars with higher HP (and lower torque) that get killed off the line by my 93 upcountry ZJ
RR refuses to make the pulley. Sprintex is mailing me a 50mm and 54mm. I'm going to start looking for a dyno soon and get each of the 58, 54, and 50mm pulleys tested.
Just spent the past few days troubleshooting oxygenated brake lines to find out that since I converted to rear disc brakes with a D44 that I have to disable the ABS by pulling the fuses and relay. 84oz of DOT3 later that is.
I bet Sprintex sends the wrong ones. They might have the wrong mounting. Hopefully not.
Could just pull off your pulley and send it to Pulley Boys as they will make one.
I bet Sprintex sends the wrong ones. They might have the wrong mounting. Hopefully not.
Could just pull off your pulley and send it to Pulley Boys as they will make one.
I would like to think it's the right one. I had to make it well known it wasn't the one with 4 bolts on the face of it. At least one of them should be right and I'll get to play with that one while I wait on the other one to arrive.
They won't be plug and play though. Going to need to shim'em up.
I got the correct pulleys... but I realized changing it takes more than just a simple allen wrench. They're mailing me the tool I need. Will be here Friday'ish, assuming it doesn't go through Baltimore.
I got the new pulley on. Getting a consistent 4.7-5.5lbs at WoT. Me rikey.
Damn AC clutch is chattering again. Every time I remove the belt it acts up and I need to recharge it. I have a leak somewhere that's magically connected via an interdimensional vortex to my serpentine. Anyone found a way to fix that yet?
The 50mm.
I got it on there and started cranking with some red loctite on the bolt... then it bottomed out before even contacting the pulley at which point I realized the bolt needed to be shortened. I thought I was ph*cked for sure.
After I took the SC off and brased the rotors with a poolstick covered with a microfiber towel I was surprised at how easily it was to get out.
Ended up cutting a little over a quarter inch off of it and not loctiting the bolt this time. The shims and pulley got the red stuff of course. There's no belt slippage despite the thing was annodized black. THere's wearing off though. I can tell it accelerates with less pedal and maintains cruise at a slightly lower RPM than before. I'm always watching my gauges like a hawk.
I think I'm going to go take it for a spin on the interstate and see if it's under boost cruising at 65 and how much easier it is to pass.
It jumped around from 4.7 to 5.5 the other day on regular 45-55 MPH roads at 90~ degrees.
On the interstate today it frequently hit 6.2 at WOT while cruising at 60-70 MPH. Mostly was doing 5.3-5.7.
You have to hit 11-12 in colder weather conditions at sea level, at your peak. 15% difference in displacement doesn't make up for double the boost. Otherwise 11-12 is normal weather and you make more in cold weather, and I doubt that.
Last edited by CoffeeCommando; 05-17-2015 at 02:21 PM.
You have to hit 11-12 in colder weather conditions at sea level, at your peak. 15% difference in displacement doesn't make up for double the boost. Otherwise 11-12 is normal weather and you make more in cold weather, and I doubt that.
We've been thru the numbers before. It is not just 15% less displacement engine equates to only 15% more boost. That is just Wrong.
49mm SC pulley on let's use 62 CI displacement SC will put out 409.58 CI air/1 engine cycle. 1 engine cycle of a stock 4.0L will take in 242 CI. The pressure ratio is 409.58/242= 1.6925.
50mm SC pulley on let's use 62 CI displacement SC will put out 401.57 CI air/1 engine cycle. 1 engine cycle of a stroker 4.6L will take in 280 CI. The pressure ratio is 401.57/280= 1.434.
The 50mm SC pulley vs. a 49mm pulley is costing you about 0.5 pound boost. A 68mm TB vs. 70mm TB maybe another 0.5 pound boost. Restrictive air intake another 0.5-1.0 pound boost. Open element air filter sucking hot less dense engine compartment air will increase IATs and decrease power.
So the real comparison is the Pressure Ratio difference, 0.6925 additional air vs. 0.434. That is where the difference is between the 4.0L and the 4.6L. It is not just 15%, it is like 59.5% more pressure ratio for the 4.0L 49mm vs. the 4.6L 50mm.
So 0.6925 x 16= 11.07 pounds boost with 70mm TB and restrictive stock head and cam and
0.434 x 16 = 6.9 pounds boost but with only a 68mm TB and better than stock flowing head and mild cam, all will decrease boost some to 6.2 pounds boost. WOW that number sounds familiar.
The numbers make sense and support the findings- 4.0L with 49mm SC pulley, 70mm TB, stock head and cam can make 11 pounds boost. 4.6L with a 50mm SC pulley, 68mm TB and better flowing head and mild cam can make 6.2 pounds of boost.
It's not a pissing match on who makes more boost, it is just the facts.
Cold day, more dense air, slightly more boost. Sea level vs. elevation, slightly more boost.
Remember, Boost is really a measurement of back pressure going into the engine. Same for same, A more restrictive and smaller displacement engine will have more boost than a freer flowing engine and bigger displacement. More boost does not necessarily mean more power. Big valve ported head and cam will decrease boost 1-2 pounds but make more power.
It has been so long, what are you doing for tuning again? What injectors? timing retard? Controller? IATs?
Last edited by CobraMarty; 05-18-2015 at 04:37 AM.
04-14-2015, 01:13 AM
