Hi. Newbie here.
I've had a quick look around but couldn't find any info i'm after.
I've picked up 2 SC14 s/c's and want to know if the serpentine harmonic balancer off a later model 6 like an EF will fit onto an Alloy head 250 x-flow. The pulleys are the main hurdle at the moment as i don't really want to go with a gilmer setup ( i still might need to go this way to get the proper ratio, just want it working first). Any other info regarding fitting of these would be apprieciated.
can't help you with the swap of harmonic balancers but if I recall from my 250's there are threaded holes in the front of standard balancer which you could use to secure a blower drive pulley. Also be careful on the blowers to correctly support the input shaft, this is a weakness which you need to address. also keep in mind belt whip will destroy even correctly supported blowers.
am interested in hearing how you go with this. have fitted one to an eb falcon but found it ran out of puff around 3500rpm, think it heated the air to a point where thermal inefficiency took over volumetric efficiency gains.
These blowers need lots of belt wrap if you are using 2 with a very long sepentine belt. Using a VN V6 commodore power steering pulley should get you a ~1.4:1 overdrive ratio then all you have to do is machine an extra groove into the blower pulleys. Try mounting it to your existing harmonic balencer. My friend was going to do this on a hemi 6 using an alloy motor plate. We worked out that at the above drive ratio the blowers would THEORETICALLY support ~400fwhp and give ~12psi. He canned the idea after not having enough spare time to make the plate and the questionable strength of a 300,000km+ motor which had bore lips when the head was off last.
Thanks for the replies. Yeah i've done a little research on these s/c's and found out that in theory i could spin 1 to 12000 rpm and will give 7 psi but this would be heating it air too much and at that speed. Over 11k the resin coating on the rotors will start to break down. Thats why i'm going for 2 and hopefully do upto 10 psi at slower rotor speed.
Belt whip? i'm assuming you mean when the clutch engages and it has to spin up to speed. I was going to run them full time to avoid this prob even though it would have been kinda cool to just flick a switch for extra grunt.
I did forget about the bolt holes in the harmonic balancer, i'll look into that option as well as the time gets closer although would be neater and better balanced with just a balancer swap, just need to buy a MIG welder first then the project can get going.
Firstly i want to try a blow thru carb system (pressurised box). Main reason for blow thru is that these s/c were not designed to run fuel through them and will be the least costly, plus i can run an intercooler this way too. If i can't get it going right or even if i do and decide to chase some extra grunt i'll go EFI but i'll give it a good go with the carb first.
[QUOTE=Jewboy] Belt whip? i'm assuming you mean when the clutch engages and it has to spin up to speed. I was going to run them full time to avoid this prob even though it would have been kinda cool to just flick a switch for extra grunt.
Actually belt whip occurs on street cars where throttle is opened and closed regularly. This also stresses blower as rotating inertia is constantly being fought both accelerating and decelerating) If you can get a look at some of the older street setups on gm etc rootes blowers you will quite often notice they have quite a few extra idler pulleys than the racing setups you most commonly see. This is to reduce belt whip. If you watch the drags you will also notice they often fling belts when backing off and reapplying throttle mid pass, I am led to believe this is partly due to belt whip.
Hope this helps as its something I know very little about.
Yeah after reading about needing a fair amount of belt wrap i was going to use an idler close by to try and get close to 3/4 coverage on the pulley.
ebxr8240, I saw that on another post but i'm going for a carb in a box setup as i'm want to try and be more hands on on this project. I'm not after show quality since you haven't seen this car. I'm hoping that with all my effort going into it i'll have it done with minimun cost, upto $1500. The 2 s/c's only cost $200ea, Of course if i need to buy a gilmer setup and intercooler this will blow the budget and i'm not including the cost of the MIG welder.
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