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Stock Intake Manifold Modifying?

prove_it

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Jul 3, 2008
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That Hawyer manifold is huge! Nice gains though. massive increase in power all over the place.
 

Ralli380Gvr4

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^^^
Yeah and they offer a lifetime warranty /ubbthreads/images/graemlins/smile.gif

Quoting 381gvr4:
Trust me, I'm in the same boat. $250 would be the highest I think I would go. I have seen SMIM, like magnus for about that price range, used on epay..... Who knows, he may not respond to the discount. I'll update when I hear back. /ubbthreads/images/graemlins/dunno.gif


Cool man, let me know what you find out.
 

381gvr4

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Quoting 381gvr4:
Trust me, I'm in the same boat. $250 would be the highest I think I would go. I have seen SMIM, like magnus for about that price range, used on epay..... Who knows, he may not respond to the discount. I'll update when I hear back. /ubbthreads/images/graemlins/dunno.gif



NO GO ON GROUP BUY! $440 IT IS FOR EXTRUDE HONE...... Anyone else know of local shops that do extrude honing??? FFWD is not the ONLY ones. EH has been used by hotroders for decades!!!
 
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H05TYL

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Quoting belize1334:
I'm still intrigued by the idea of running Cyclone runners w/ a SMIM plenum. Since the butterfly valves are built into the 3rd section of the manifold (that bolts to the head) you could just disassemble it at that point and then build a SM plenum with normal runners that then bolts to the cyclone runners right before the head. You could then have velocity stacks and all that jazz in the plenum and still make use of the butterfly actuated secondaries.



Ditto.

Another option (if you can find one) would be an AMG galant manifold, same runners/cyclone but the plenum is approx 33% larger.
 

mean_green

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Park City, MT 59063
Yeah I'm looking into a business that might be able to do a group deal or even one at a time. I'll let everyone know for sure. Could work out awesome I'm not looking to make moneyz.

-Alan
 

belize1334

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I was thinking more along the lines of starting from scratch w/ the plenum...but that's pretty damn cool too. I may have to have him build one of those for me once I get everything else nailed down (which will probably be never).
 

Ralli380Gvr4

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I remember drooling over that manifold in the for sale section. Would there be a benefit to keep the cyclone system or ditching it when using something like Curt's modified manifold?
 

prove_it

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You'd still use the cyclone butterflies to improve the low end respond and torque curve. With a larger plenium though, you'll increase the top end and that's it. The cyclone manifold would stay the exact same, just with a bigger plenium for high end air flow. It's really the best of both worlds, now if only he could built a taper plenium instead, maybe make for better flow, and better cylinder distribution.

*edit: forgot to ask, but when increasing the size of the plenium with a cyclone manifold would the runner opening time change? I know most cars on the dyno like to have the butterflies open around 4100, but would a larger plenium shift that number higher?
 
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curtis

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May 4, 2003
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Clarksville TN
If some one wants a plenum done just yell. I've got alot going on and want be a 2 day quick turnaround. The first one I made (from Garfield's link above) was put it up for sale and don't know if its still available or not. /ubbthreads/images/graemlins/dunno.gif

But to add to the threads above. A 2nd gen intake want fit on a first gen head with out leaking on the outside edges. I can take pictures if anyone needs to see. I have 2 2nd gen intakes in the shop with plenum's cut off just haven't got to the building stage yet.


Now my two cents

tapered plenums are BS might be good for 20 inches of vaccum to zero but you have to remember under boost the plenum is a pressurized vessel. Air will flow and feed the head as long as the intake isn't a restriction it want create back pressure. Cross sectional area is very important and rapid changes in shape are very important as well thats why aftermarket pieces that go from round to square don't perform as well as the ones that are square to square like the hawver manifold. Plenium shape is also important but the tappered ones that perform well are over sized at the entrance from the throttle body and the T-body is angled to keep the turbulence away from the ports as the new air enter the plenum and keeps from hitting the air that is returning from the closed intake valve. Remember this air is heated and flowing at the speed of sound. You can research tuned intake manifolds and heimholtz ram effect to understand more. Theres a million pages of info on this stuff.

For example my old IC pipes I had 3 inch pipes that used a transition coupler to 2.5 into the t body. I took it out and drove it and then after I got hoem. removed the 2.5 tube and cut the flange and elbow off then took a 3 inch tube and cut it lengthwise and took large t bolt clamps and made a cone welded it up and cut to lenght then drove the car. I lost 2.5 psi of boost....Its because the transition was a huge back pressure point.



Now something I've always wanted to try is take the cross sectional area of the t body and then multiply by the amount of boost in bar to get a total na comparison...... lets say you get 30 sq inches so if you get a tube the same od as the ID of the throttle body and the same length of the plenum. Then chuck the tube in a mill and cut out a slit from one end to another and make the slits total area 30 sq inches then insert in the plenum and weld into place. What this will do is give the air coming out of the runners clean air to flow through and the new fresh air a easy passage to the port wanting to ingest air without a bunch of turbulence. But angle of exit would be important and maybe it would be better to have the air entering the port from the lower quadrant of the slit or the rear. /ubbthreads/images/graemlins/dunno.gif Only way to test would be to have a way to turn the tube after its inserted and make dyno pull after dyno pull. I bet theres gains to be made there but maybe very insignificant


I have a cyclone manifold here with boost activated controller if someone wants it I may sell it. I'm in the process of my own design right now and need some serious cnc time to finish it. Kind of been waiting on finding some blocks of aluminum.

If anyone has 2 6x3x22 pieces of 6061T6 yell. /ubbthreads/images/graemlins/devil.gif
 

prove_it

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Curtis:

You will always make my brain hurt with your incredible knowledge. This is why I am on this forum. Thanks for the info, I feel safer sending you my manifold to redesign. Keep it up!
 

Ralli380Gvr4

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Did all AMG intake manifold's come with the cyclone system?
2709_3mg.jpg

amgintakemanifold.jpg

I'm sure theses would be nearly impossible to obtain but I'm curious what the result would be on a mild street set-up.
 
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Quoting prove_it:
You'd still use the cyclone butterflies to improve the low end respond and torque curve. With a larger plenium though, you'll increase the top end and that's it. The cyclone manifold would stay the exact same, just with a bigger plenium for high end air flow. It's really the best of both worlds, now if only he could built a taper plenium instead, maybe make for better flow, and better cylinder distribution.

*edit: forgot to ask, but when increasing the size of the plenium with a cyclone manifold would the runner opening time change? I know most cars on the dyno like to have the butterflies open around 4100, but would a larger plenium shift that number higher?



Theoretically, yes. The larger plenum in this case is using the same "floor" of the IM, just "raising the roof" to increase the volume. What this does is increase the distance between the runner opening and the opposite wall, changing the amount of time it takes for a pressure wave bouncing off a closed valve to travel up the runner and ricochet off the opposite wall and then back down the runner, cramming an extra bit of air into the cylinder. I bet if you threw that manifold on the dyno and did back to back pulls with the butterflies open and butterflies closed, you'd see a different ideal crossover point compared to a stock cyclone IM.
 

prove_it

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Sioux Falls, SD
I completly forgot I asked that, thanks! I was thinking along the same lines too. Just wanted more more expert advice.
 
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