525SC Weiand 177 On A 454 MAG in Formula 242LS
03-25-2011, 04:29 PM
#11
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Summit or jegs carry the kit to change out the blower input shaft to keyed. Thats what I did. Then you can run any pulley made. If you want smaller splined pulleys though I have some I could measure and see if they'd work for you. I think the were 2.75" OD. Also on the ignition module you may be able to get away with the 24* tbolt but your idle in and out of gear around dock will suck (stalling) and my opinion is your all in advance will be too much and may cause detonation. 525scs had a much lower comp ratio than you have. The 14* v6 module allows you to run 30* all in (safe) and a healthy 16* idling. Works good that way.
03-25-2011, 08:39 PM
#12
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Blue Thunder, not to take away from Century Ultra, but if you've got a matched pair of pulley's at 2.75" for splined shafts I'd be interested. Maybe send me a PM with your number and we can talk about it. Unless Century Ultra takes them first.
03-26-2011, 01:40 AM
#13
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Summit or jegs carry the kit to change out the blower input shaft to keyed. Thats what I did. Then you can run any pulley made. If you want smaller splined pulleys though I have some I could measure and see if they'd work for you. I think the were 2.75" OD. Also on the ignition module you may be able to get away with the 24* tbolt but your idle in and out of gear around dock will suck (stalling) and my opinion is your all in advance will be too much and may cause detonation. 525scs had a much lower comp ratio than you have. The 14* v6 module allows you to run 30* all in (safe) and a healthy 16* idling. Works good that way.
I was suggesting to run a smaller lower pulley to reduce boost slightly. Since the 525SC is 7.5:1 and has 5.5# of boost and his engine is 8.75:1, a 1# boost reduction would reduce his overall effective compression ratio and get it close to the same effective comp ratio as the 525SC.
03-26-2011, 06:27 AM
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I measured the pulleys and they are actually 3" pulleys. PM me if you would like them. I also have the splined shafts that go with them.
You can surely start with the V-8 modules century and switch to v-6 modules as I did to improve manners if necessary. You really shouldn't go over 30* all in timing with your higher comp and iron heads. Plus you would gain zilch in performance between 30 and 32*. So you'll need to set the base at 6*. One other thing you should do is buy a new balancer. Older balancers can slip giving you a false timing setting. Too much timing will melt your pistons fast on a high compression blower engine. btdt.
You can surely start with the V-8 modules century and switch to v-6 modules as I did to improve manners if necessary. You really shouldn't go over 30* all in timing with your higher comp and iron heads. Plus you would gain zilch in performance between 30 and 32*. So you'll need to set the base at 6*. One other thing you should do is buy a new balancer. Older balancers can slip giving you a false timing setting. Too much timing will melt your pistons fast on a high compression blower engine. btdt.
03-26-2011, 06:12 PM
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Thanks everyone very helpful! I just checked and the blower I have already has been converted to the keyed shaft. I didn't know the difference when I bought it that the factory merc blowers had a splined shaft. I also measured the pulley I got with it. The blower currently has a 10 groove 3" pulley on it. The guy also gave me a 6 groove 2.75" blower pulley and a 6 groove 7" crank pulley. Looks like I need a pulley or two to reduce boost. Do I need a 10 groove or doesn't it matter if its 6 or 10? The tensioner pulley is obviously 10 groove. If anyone has a pulley(s) they want to sell please let me know. Thanks again!
03-26-2011, 07:11 PM
#18
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Use the 10 groove. The belt will grab better and not slip.
IMO, the pulleys you have will make too much boost for you. The 3.0" upper and 7" lower is 2.33:1 overdriven and will make about 7# of boost.
You ideally want about a 3.5 upper and 6.5 lower which should make a little less than 5# of boost. It will create less heat by spinning the blower slower and will also reduce the chance of detonation.
If its a 525SC blower, then you need to use a Dominator Carb to fit it. A 1050 is bigger than you really need and biger than the 525SC needed, but it will work fine.
I would guess you will be about 475hp or so.
IMO, the pulleys you have will make too much boost for you. The 3.0" upper and 7" lower is 2.33:1 overdriven and will make about 7# of boost.
You ideally want about a 3.5 upper and 6.5 lower which should make a little less than 5# of boost. It will create less heat by spinning the blower slower and will also reduce the chance of detonation.
If its a 525SC blower, then you need to use a Dominator Carb to fit it. A 1050 is bigger than you really need and biger than the 525SC needed, but it will work fine.
I would guess you will be about 475hp or so.
03-29-2011, 01:05 AM
#20
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The fuel pump will be fine for the power you are going to make. Unless you want to start spending a ton more money, I wouldn't worry about getting different heads. You could get some mild porting done on you stock heads and have the combustion chambers enlarged to about 120cc. That bring the CR down to about 8.5.
