New benchmark for stock-type heads!

[VadersV6]

Nice work. Maybe you go to corral.net once in awhile? My user handle is 32VHEMIJR, and most of my posts were in the SVT/DOHC forum. My research showed something different with forced induction and plenum volume. half the displacement of the engine works great if the runner entries are located properly. The response will be much quicker, and the bottom-mid of the curve will be stronger due to the lack of a pressure sink. Big volume is ok on race duty engines that spend their lives above 5000rpm, but otherwise, the reversion wave effect is greatly softened and dampened out with too much plenum volume. The returning wave wont bounce off the air mass in the plenum. It will more or less dissipate. into the plenum, and will have far less strength when it returns to the valve.

 

[Alky V6]

Nice work. Maybe you go to corral.net once in awhile? My user handle is 32VHEMIJR, and most of my posts were in the SVT/DOHC forum. My research showed something different with forced induction and plenum volume. half the displacement of the engine works great if the runner entries are located properly. The response will be much quicker, and the bottom-mid of the curve will be stronger due to the lack of a pressure sink. Big volume is ok on race duty engines that spend their lives above 5000rpm, but otherwise, the reversion wave effect is greatly softened and dampened out with too much plenum volume. The returning wave wont bounce off the air mass in the plenum. It will more or less dissipate. into the plenum, and will have far less strength when it returns to the valve.

In essence turning a large single plenum intake system into more of an IR intake system. Which would fit nicely with an engine configured to run in the upper rpm range.

 

[Ed Valvo]

SGRIM,
There have been iron head 109 blocks turning 7000 RPM. Some of the ole Oregon boys roughly 8-10 years ago, specifically Terry Ryan, were running 10's at 130 mph and spinning the engine pretty high. This was before everyone was running girdles, GN1's, roller cams, FAST, Axcel, Extender chips, etc.... Just plain ole 7th and 8th injectors that he manually activated depending on what his state of tune required. Kinda funny watching a guy going down the track with his eyes on the EGT gauge. You'd think he would look down the track to steer. Where is he now anyway??

 

[turbofabricator]

SGRIM,
There have been iron head 109 blocks turning 7000 RPM. Some of the ole Oregon boys roughly 8-10 years ago, specifically Terry Ryan, were running 10's at 130 mph and spinning the engine pretty high. This was before everyone was running girdles, GN1's, roller cams, FAST, Axcel, Extender chips, etc.... Just plain ole 7th and 8th injectors that he manually activated depending on what his state of tune required. Kinda funny watching a guy going down the track with his eyes on the EGT gauge. You'd think he would look down the track to steer. Where is he now anyway??

Here he is: Terry Ryan's Performance Specialties Great guy to know. Alot of fun to hang with and talk engines. He's a real easy going guy, with out an ounce of "attitude" in him.

 

[turbofabricator]

Here's the other manifold for the 5.4 4 valve. Both are avilable. Sorry for the hi-jack. This should really be it's own thread.

 

[GNVYUS 1]

Turbofab, what no velocity stacks?? :tongue:

You and Vader need to hook up for a killer GN intake, I am sure you guys could find a much better product than the ported stocker for guys with bigger heads.

Still no post on the $$ for 300cfm TA heads??

 

[Three77]

What do you guys think about the smaller intake port/higher velocity theory?

I've always wanted to play around with a 4cyl head to test it out. I understand the idea, just wanted to know if anyone has actually done it and what the results were.

 

[turbofabricator]

What do you guys think about the smaller intake port/higher velocity theory?

I've always wanted to play around with a 4cyl head to test it out. I understand the idea, just wanted to know if anyone has actually done it and what the results were.

Small ports have no place in a turbo engine. The larger you can make the port without sacrificing low lift flow numbers, the more peak power it'll make. Years ago David Vizard completely removed the port dividers in a SBC head. (the wall between the shared ports on the intake side) and said it picked up measurable power when turbocharged. (I forgot the actual number) Not really needed today with the heads that are available for the SBC. But port volume is VERY important on a turbo head, especially with port EFI. With a small port and a turbo you risk the velocity reaching port stall, and that would be bad. Some theorize that the air becomes super sonic, though I don't think that has ever been validated. There's alot of info on this topic here: General Engine Tech :: Speed Talk - Auto Racing Forum You can spend HOURS reading everyones theories, only to feel dumber than when you started. Darrin Morgan posts on there all the time. He is the cheif R&D cylinder head guy at Reher Morrison. He has a WEALTH of knowledge that he shares. Just when you think you have the answer to some airflow issues, you end up back at square one! Just read up on stuff, and try SOMETHING and then make adjustments as you go.

 

[Nick Micale]

Turbofab, what no velocity stacks?? :tongue:

.....Still no post on the $$ for 300cfm TA heads??

Since all the heads, and engines, we do are to customer's specs, we do not have a published price list.

There are various levels of port work, different valves and springs and other variables that affect the final price.

We are always happy to quote a price so please contact me by direct e-mail or phone to discuss your particulars.

 

[Alky V6]

I hear ya Nick. Good work.

 

[ijames]

My research has me thinking that a plenum volume needs to be 2.75 timed the displacement of the engine. That's why I built my plenum box the size I did. Our 3.8's need 2.75 gallons of plenum volume. (in theory) They come from the factory with nothing near that. I haven't measured it, but might have to now just for grins. Building a manifold with 12-14" runners is kinda challenging with hood space being like it is. I will tinker with the idea, thoug and see what I come up with. So, a three gallon plenum and 13" runners............I'm on it..... soon.

How about a cross-ram style, like those early Dodge's with each carburetor over the opposite wheel? Come off each head with almost horizontal runners and two plenums, one above each valve cover. Makes it two 3-cylinders, and hard to adjust the valves unless you make it easy to unbolt each plenum from the runners, but should clear the hood and give you the runner length you want. Perfect for twin turbos, or just put a Y in the uppipe from the intercooler. The runners will be about as tall as an injector so the fuel rails can bolt down flat to the top of the upper runners with the injectors reaching down to the lower runners just before the intake flange. Maybe open the driver's side throttle body with the normal throttle cable and use a "slave" cable to operate the other throttle body so no linkage adjustments if you just lay the passenger plenum to the side to remove the valve cover.

 

[DGC]

Cosidering your TA headers for next step in build. I appreciate all the information at your web site, but would like to ask what gains I might expect on GN1 stock ported heads from Tom, with the TAs versus stock. Price point is a bit high, but I am trying to do it right and only once.
Thanks, DGC

 

[VadersV6]

next post..

 

[VadersV6]

Small ports have no place in a turbo engine. The larger you can make the port without sacrificing low lift flow numbers, the more peak power it'll make. Years ago David Vizard completely removed the port dividers in a SBC head. (the wall between the shared ports on the intake side) and said it picked up measurable power when turbocharged. (I forgot the actual number) Not really needed today with the heads that are available for the SBC. But port volume is VERY important on a turbo head, especially with port EFI. With a small port and a turbo you risk the velocity reaching port stall, and that would be bad. Some theorize that the air becomes super sonic, though I don't think that has ever been validated. There's alot of info on this topic here: General Engine Tech :: Speed Talk - Auto Racing Forum You can spend HOURS reading everyones theories, only to feel dumber than when you started. Darrin Morgan posts on there all the time. He is the cheif R&D cylinder head guy at Reher Morrison. He has a WEALTH of knowledge that he shares. Just when you think you have the answer to some airflow issues, you end up back at square one! Just read up on stuff, and try SOMETHING and then make adjustments as you go.

The cross sectional area will determine when the charge reaches sonic speed. Some people say it doesnt, but that contradicts all the info out there. By removing the divider, the velocity has dropped significantly, which raises the rpm where the air charge reaches sonic and cant go any faster...by a huge margin. Choose cross sectional area to determine where you want torque to peak. Do the math to find out where the hp should peak with that peak torque rpm number, and then choose the correct runner length which will provide the passive supercharging, or resonant tuning, in the range between peak torque rpm and 1000rpm above peak hp rpm. Half the swept volume of all the cylinders is what you want on a street motor. Ever added a plenum spacer on a buick and noticed you didnt gain anything? Not talking about the RJC thing....it didnt improve because its already too large. The only benefit of a huge plenum is to equalize the pressure and flow pattern at the inlet of all the runners. Its a band aid for a poorly designed intake where some runners draw more air than others. Took me many years of work to figure this stuff out. And its not a bunch of crap just swiped off the internet. Its all info I found first hand on the dyno.

 

[turbofabricator]

Its all info I found first hand on the dyno.

BUT!.............."We don't race dyno's". ('course you've NEVER heard THAT before )

I'd love to talk intake/head design with you in another thread. Now, back to the new heads making BIG flow numbers.........

 

[SloGN]

The only benefit of a huge plenum is to equalize the pressure and flow pattern at the inlet of all the runners. Its a band aid for a poorly designed intake where some runners draw more air than others. Took me many years of work to figure this stuff out. And its not a bunch of crap just swiped off the internet. Its all info I found first hand on the dyno.

i have oftened wondered about plenum volume before. To me i would think that a larger plenum would allow the larger area to have a less of a vac pull on it when the valve cracks open. so the vac would have a larger area to act on instead of thru the TB and filter set-up.

 

[SloGN]

BUT!.............."We don't race dyno's". ('course you've NEVER heard THAT before )

I'd love to talk intake/head design with you in another thread. Now, back to the new heads making BIG flow numbers.........

Big flow #'s don't win races either

 

[turbofabricator]

Big flow #'s don't win races either

True.......in my world, cutting a good light wins more races than extreme power does. But then again, running someone down with HIGH mph is always more fun than letting them try and catch you. Now, I need to make the "tree-reader" that all those Comp guys use. :biggrin: