You know my cam specs

Cold start idle is around 40kpa at 1150rpm and IAC wide open at 310. Warm idle is around 700rpm and 50kpa with IAC at ~70.

Yea my theory is the IAC is just small for this size engine with decent vacuum...not sure why everybody elses setup doesnt do the same thing though. I would call it the throttle body, but my nick williams TB did the same thing.

So how do you control idle rpm? Just with spark?

The entrance or exit?

Its definitely IAC. Notice early in the video when I put my finger over the port momentarily and the noise stops? The PCV is vented to atmosphere. See above for IAC counts.

Yep, decided to keep it going instead of making another one for the blower build. I guess the second setup for this truck if you just count turbo or blower....but for the truck, went through 3 turbos and now this blower, and had some engine parts replaced along the way.

By the way, you need to call your twin and harass him for not setting up a meet this year.

 

You still need that measurement?

Any other measurements you need.

 

Looks good all back together Richard, street truck

 

4 3/4in center to center on the idlers.

 

I'd smooth and port both the inlet and outlet if the IAC area. If they air can go through there more smoothly, shouldn't be as loud. My old KB blower was same way at first start too.

 

Yea I know the cam specs... lol.

I was just pointing to the fact that I knew that mild of a cam with 402" would pull huge vacuum. I thought this would be your issue. that is a LOT of vac!!!

I'd bet you dont need anywhere near that much RPM at idle cold while pulling that much vacuum. Its a 'sweetheart' cam... i'd be looking to near stock idle RPM values. Back it down to say 950 and see if the problem goes away a little.

 

what size pulley do you have on the blower and how much boost are you getting?

 

Looks like the whipple bracket has the idlers about 4.25" apart, which explains why I cant get the 2 big pullies on there. Oh well, they wont match since I have to use the metco one on the right to clear the bracket, so much for symmetry.

Ill try porting the IAC entrance, couldnt hurt I suppose. I wonder if the 8.1L used the same IAC valve, seeing as how its a huge engine I didnt know if it would have a bigger one. Yea I probably could lower the cold idle rpm some...

I got to work on the HD tensioner some, since I got everything else working I may as well change it up and try to break it again. Heres the issue with using it and why I was asking so many questions to the Maggie guys:


It obviously needs to come way out so I had some spacers/shims made in 3/8", 1/8", and 1/16" (which I dont have yet) to see if I could get it right. I had holes drilled along the edge that lines up with the tensioner pin and are every 36 degrees to give some adjustability. Really this means any tensioner that shares that bolt circle can now be used.


Eventually I am going to get some 5/16" rod to pin them all together and into the accessory bracket so they dont rotate, but for now a sacrificed 5/16" bolt works just fine. I plan to weld them together once I finalize what I need.






And here it is installed,





A lesson I learned is to actually measure where the belt rides on each pulley vs where the end of the pulley is since some of them have thicker flanges. Based on using a steel straight edge and measuring to the belt, I have the alternator, tensioner, and crank within half a millimeter, and the blower pulley to those within probably 1mm. I got lazy and didnt check the PS pump to that since it has a lot of thrust clearance.

Also here are the results of some testing on the tensioners I did, thought it would be good to put here too.




I should start selling a kit to convert whipples to 8rib since so many of these parts are custom

Oh and the pulley on there is a 2.9" and should be around 13psi or so.

 

Nice work man. Go let it eat now!

 

Solid work! Thanks for the tensioner data too!

Can't wait to hear how it runs!!