I have been working on making an intake manifold for our all motor cars. The issue with the VR6 motors is that the available log manifolds are all designed for high boost. I know there are some issues to take into account when building a manifold fo an all motor car.

Let me know your input... I have the general idea but we are very limited in our engine bay for room/fitment so I am trying to weigh all available options. I don't think making one to large is an issue because there just isn't that kind of room to work with in the engine bay. We can stand to take a any loss in low end because even in stock form this motor produce a lot of torque. Where our motors are at now we keep gaining torque with minimal whp gain.

Any help/insight/thoughts are appreciated.

The motor we are working with is a 2792cc 2.8L engine.

Thanks.


Modified by billyVR6 at 6:37 PM 7/29/2004

 

Hmm, im not sure not sure of the acual formula off the top of my head, but where exactly will this engine redline? You need to design a manifold that will let the engine breathe well where it likes to make power, ex. short runners for high rpm useage, long swoopy ones for low end torque. It sounds like you know this basic info already though. I have a few good references ill check out and get back to you.

 

That would be great...

Yeah, we do not need torque at all... I am actually hoping that these larger cams that I am about to set up take some away. We are concerend with top end... well, lets say 5K on up just because out motors do not rev to 9K like most Honda engines. We make peak power just around 6100-6200 RPM, shift points for the way the motors are currently set up are at 6600-6800 RPM.

It would be nice to get the power band up in ther 7K area...

As of right now my car's fuel cut is at 7200rpm... from peak power output to the cut the motor falls off from 194whp to about 168whp. I am not really looking for just "peak" numbers as I know they will be minimal.... I want to see the power extend out in a broader curve with less of a drop off.

Bill

 

you are in pa... do you know who joe aragona is? i believe that he built the vw motor that michelle costa just won an nhra comp race with(??)... they are working on a water-cooled vw all-motor car as well.

one thing you might do is find somebody with the engine analyzer pro software, i believe that it will calculate some intake manifold dimensions... as well as exhaust tube diameters and lengths, etc... but you'll have to feed it exact headflow numbers in order to get accurate results.

 

how do those Schrick variable manifolds work ? aren;t they pretty good with their cams ? just curious, been years since i've looked at VWs

greg

 

From what i understand is they work failry well, but theres an all to common torque dip that occurs when using them.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by danimal &raquo;</TD></TR><TR><TD CLASS="quote">you are in pa... do you know who joe aragona is? i believe that he built the vw motor that michelle costa just won an nhra comp race with(??)... they are working on a water-cooled vw all-motor car as well.

one thing you might do is find somebody with the engine analyzer pro software, i believe that it will calculate some intake manifold dimensions... as well as exhaust tube diameters and lengths, etc... but you'll have to feed it exact headflow numbers in order to get accurate results.</TD></TR></TABLE>

I have never heard of Joe Aragona or Michelle Coste, any info? I am very into water cooled VW drag racing the only person that I am aware of that have anything competitive is Nate Romero and his 1994 20/20 Corrado... I don't even thing he does NHRA though more focused on NOPI, IDRC and Battle.

Flow numbers are not a problem for our cylinders heads at the shop. The engine analyzer is a good thought and sounds like a nice winter project to be able to get all the correct data. Get this though... because of the design of our head there have been a few cases were better flow number heads made less whp than heads with a bit lower flow numbers.

Bill

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CHEETAH &raquo;</TD></TR><TR><TD CLASS="quote">how do those Schrick variable manifolds work ? aren;t they pretty good with their cams ? just curious, been years since i've looked at VWs

greg</TD></TR></TABLE>

Well, the VGi ....I think it has it's flaws and is very expensive @ $1500-$1750 new. The VGi will produce torque but very minimal whp up top. Here is the deal with the torque it produces... it has a about a 20-22 wht gain at at 3800-4200 RPM (depends on how you set the crossover)... and that gain spikes up real quick in a very short RPM area. That is fine for daily driving I guess.

The big thing that everyone totally overlooks is that after the "spike" you lose power. A few people have claimed that they have stuck the flaps wide open and the manifold reacted close to an OEM manifold with a bit if a whp gain at peak. I am about to find out because we got a busted VGi coming into the shop... the plans are to clear out the guts of the intake and run it open.

What I do like about the VGi is that the throttle body neck is waaaay less restrictive over the modified OEM and or Euro manifolds that we are currently running. We'll see....

Bill

 

here is some info on joe aragona, i believe the all-motor vw deal he is working on is for a guy with the last name of wolfe, maybe joe has already designed an intake manifold:

http://www.competitionplus.com....html
http://www.jitterbugracing.com/IMS.html

those better h.p. numbers with less flow seem to indicate better port velocity? some head porters like looking at the flow numbers at mid-lift, because that's where you might see more air flow because of better port velocity... engine analyzer pro should reflect those numbers with better power figures.

bottom line is that motors are air pumps, you gotta be able to feed a motor x amount of air to make x amount of h.p.

your 6100-6200 rpm for peak power indicates that you might need a lot more airflow for that huge 2.8L displacement... unless it's a camshaft/intake bug that's limiting the flow?

post the peak headflow number and it's associated lift, with the inches of water it was tested at, and i'll run the math to see where the limitations are.


Modified by danimal at 9:33 AM 7/30/2004

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by danimal &raquo;</TD></TR><TR><TD CLASS="quote">those better h.p. numbers with less flow seem to indicate better port velocity?</TD></TR></TABLE>

Yes sir... you hit the nail on the head.

As for Joe Aragona... all of that is Air Cooled VW Drag Racing, totally different beast all together. If the guy you are thinking has the last name of Wolfe then it is most likely Paul Wolfe who is into both Watercooled (had a 10 sec Rabbit years ago) as well as the Air Cooled drag race circuit. What rang a bell was the Jitterbug link, that is a very active and dedicated Air Cooled website.

As for the cams... the stock motor produces peak at 5800, the motor does respond well to certain cams sets. I pretty much have the largest available cam that you can run on a hydro lifter set up that is waiting to go in the car.... it is supposed to make an averageof 8-10 more "peak" whp than the aftermarket set I have now... should have those results in about two weeks so we'll see.

I can get flow numbers from the head that is actually on my car the next time it gets torn down.

I know the idea and all the theory... I guess I was more looking to hear from you guys on what manifolds you have seen work on your motors, why one was better than the other, etc., etc. You know what I mean? Like what would make the Edlebrock better than the current JG or vice versa.
Stacks in the plenum, different radius runner inlets, etc., etc.

Thanks for the input, keep it coming.

Bill

 

you better go re-read those links about joe aragona, he's worked on all kinds of motors! he is not just an aircooled vw guy.

the wolfe i'm talking about is the brother of the jitterbug racing site creator, we could be talking about the same guy, but it sounds like you haven't heard about his new project? joe can give you the details.

there is also some general manifold info on the web, maybe http://www.grapeaperacing.com?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by danimal &raquo;</TD></TR><TR><TD CLASS="quote">you better go re-read those links about joe aragona, he's worked on all kinds of motors! he is not just an aircooled vw guy.</TD></TR></TABLE>

I gotcha... I did just skim it all because I was at work at the time.
The air cooled comments I made were just in reference to all the bug/air cooled motors on the links. That Subaru engine set up on that one Altered is interesting.
Thanks for the links.


Billy


Modified by billyVR6 at 10:42 PM 7/30/2004