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Discussion Starter #1
What gear ratios are you guys running?
I've done some searching but people without blowers swear to use 3.73's, but I've heard of guys running 4.30's with boost...
With the new job, I'm looking at getting PI heads with a 6psi AED and gears, TC of course too.
I don't plan on forging it anytime soon, so 6 PSI is going to stay.

I would like 4.10's, but I have no experience even driving in a Boosted of any type car.
 

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3.73's are common everywhere, not just on boosted cars. I've heard boosted people swear by and swear at anything 4.10 or taller. I say it's up to what your needs are. For a daily driver, you might wanna max at 3.73. If it's a racer, go wild.

That's just my opinion, though...
 

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i'm naturally aspirated with +108,000 miles running 4.10's with no issue. gas mileage is around 20 on the highway running 89/90 octane ethanol with a s275/60 r15 rear tire
 

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According to AED's website:

How much boost do I get and when ?

allen-superchargers.com/faq said:
The use of an Eaton (positive displacement blower) allows an almost constant boost level over the entire engine speed range. The centrifugal kits ramp up boost as engine speed rises, and are thus rated as a maximum. The average amount of available boost with a positive displacement blower is therefore higher even with a lower peak boost rating, and translates to a better driving and quicker vehicle. It also does not require the use of lower gears to keep the engine "in boost".
Don't know if that answers your question, but it makes sense to me.
Its seems the gears you want would depend on whether you're using a roots blower, or a centrifugal type blower, and of course your personal tastes.
 

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02 Explorer Pioneer
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I think 3.73 would be a good compromise but what do I know I am still running 3.27's with a roots
 

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I've got a lot more modifications and am moving a lot more air than your average out of the box AED set up but as it is even the stock 3.27's don't feel all that bad. I've got 3.73's sitting in a box in my bedroom, waiting to go in, but i'm already able to blow the tires off through first and second gear from a dead stop.

Since you're going with the Positive Displacement blower and have the benefit of the PI head swaps 10.4:1 compression ratio (which will improve low level torque numbers) I'd think 3.73's would be plenty for you're car. 4.10-4.30's would be better for a centrifugal style blower.
 

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3.73's here...wouldn't have it any other way for a street/strip car.

Most AED cars make gobs of torque down low so over gearing is not required. My car made 355 RWTQ at 2,500 rpm and 380 RWTQ at 3,200 rpm.

Using 4.10's is overkill on an AED car unless it's for the strip only.

A-Train
 

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I am running 4.10's outback. But I do have a manual trans. At the track I have to run out 4th gear with the shift light blaring. My car made 360 horse at the wheels. my car tops out at 112mph in 4th, and into 5th I go. I plan on stepping down to 3.73's when I put in my new engine....whenever that happens.
 

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Well i just sold my Truck yesterday for $3000. So looks like i will be ordering my TEA heads this week.

My Engine project has been a slow assembly..lol. So far I have the shortblock built.
-93 teksid alumium block, torque plate bored .020" over
-forged Cobra crank
-fed Mog race rod and main bearings
-Manley H-beam rods
-JE Forged 9.5:1 pistons
-ARP main bolts
-ARP 2000 rod bolts
-FRPP high volume oil pump, SHM billet pump gears
-Mark8 oil pan
-ARP head studs
-Meizer electric water pump
-PI coolant tube
-VT Stage 3 blower cams

The heads like I said are going to be Total engine Airfows, fully ported & assembled with comp springs, stainless cut valves, bronze valve guides, and better keepers. I have to order those this week, get a few more gaskets and bolt the heads on and shes ready to go. Chris
 

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Beer and Cheese
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7,386 Posts
Sounds fun, this motor will be with the Vortech?

I see you have the MSD DIS-4 from your sig, just a warning, they go out and fail with out warning. I'd buy a adapter plug and keep it in the glove box if your ever in the middle of no where.
 

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MaleWhore
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3.73...they work great with my pi-vortech....
 

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Sounds fun, this motor will be with the Vortech?

I see you have the MSD DIS-4 from your sig, just a warning, they go out and fail with out warning. I'd buy a adapter plug and keep it in the glove box if your ever in the middle of no where.

funny you mention this. I bought the unit new and one of the channels were bad right off the bat. the mailled me a whole new unit with another wire harness and install kit. I have two of te plugs, one in the glove box and one in the tool box at home. I only bought the MSD box, because I kept having issues with spark blow out. Chris
 
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