Turbobricks Forums

Turbobricks Forums (https://forums.turbobricks.com/index.php)
-   performance & modifications (https://forums.turbobricks.com/forumdisplay.php?f=13)
-   -   Cam and I built one of these David Vizard budget flow benches (https://forums.turbobricks.com/showthread.php?t=364714)

shoestring 06-21-2022 02:17 PM

Cam and I built one of these David Vizard budget flow benches
 
So the way these benches work is that you hook up a shop vac (the nuttiest one you have) to a "cylinder" that the head sits on, and there's a capillary tube that feeds a manometer. Ours has 80 inches of water in it. You run the vac, open the valve to say 0.300" and read the number. Say it pulls the water to the 30" mark. We started at 40" (80" in a U-shape is 40" per leg), so it's pulling 10" of water times 2 (there's 2 legs of the manometer) for a total of 20". You do some mods and remeasure. Well this time it only pulls say 9" for a total of 18. There's an obvious improvement here because the capillary tube which is located in the cylinder is seeing less vacuum (more air is cruising past the valve). It's not 10% in this example because there's some square roots involves and stuff but that's not really important and not a good idea to focus on.

And while I can't tell you exact flow numbers (because we don't know them), I can tell you that for a fact the B21F intake outflows the B230F intake by a fair margin. The head used was the one off of our LeMons car which has some bowl and valve/valve seat work but is a stock 44mm valve. There is ZERO chamber work on this head, but it is cut about 2.25mm below stock 146.1mm spec and they measure between 44 and 44.5cc.

So here's the real flow result of the head off of our LeMons race car that has the standard 44mm intake valve with a multi-angle valve job and bowl work, and a 38mm exhaust valve, also with multi-angle valve job and bowl work, some of which includes filling the long side turn. As measured at 28" on a Superflow at R&L Engines, Dover, NH:

LIFT--------INTAKE CFM---------INTAKE W/MANIFOLD & TB-------EXHAUST
0.050..............24.1........................... ...23.5.............................23.8
0.100..............52.5........................... ...49.0.............................48.5
0.150..............77.0........................... ...76.5.............................67.2
0.200............102.9............................ ..97.0.............................82.5
0.250............125.2............................ 113.8.............................91.2
0.300............148.8............................ 125.7............................100.2
0.350............163.9............................ 134.0............................107.1
0.400............168.2............................ 141.0............................111.3
0.450............171.9............................ 144.0............................114.5
0.500............173.9............................ 142.0............................116.7
0.550............175.2............................ 142.0............................117.8
0.600............175.6............................ 141.9............................118.2


As I've posted a million times before, we make 144 whp with this head and a K cam. This is not the EXACT intake and throttle body we use, but they are all stock, unmodified pieces.

Also note that this head has a 38mm exhaust valve with a strong amount of bowl work but doesn't flow a lick more than a stock valve on a stock port! Why? Valve shrouding. Again, I can't tell you exactly how much of a gain in flow it is, but I can tell you it's a LOT.

Ask away, I just wanted to get this put up, I've been sitting on the info for a little bit. the only thing I've been able to do with the intake that's worth a crap is grind out the throttle body stud bosses that get in the way of the #1 and #2 runners in the plenum. You've got to take them all the way off, like on the opposite side, and it's going to expose the studs, so you may need to pull the studs and do some vacuum-leak prevention with some sealer or something. Those bosses make a bunch of turbulence at higher (>0.300") valve lifts and removing them helps alleviate this.

This flow test also answers the question I've had as to why Volvo cams are ground either single pattern or with a little more intake lobe: they need it. There's a 75% "rule" (let's call it a guideline) for exhaust-to-intake relationship. This is lobe-to-lobe, not just a single lift point, so hopefully you have a calculus person in your house like I do. If you've got less than 75% exhaust flow compared to the intake, you need more exhaust lift/timing. The opposite is true if you have more than 75%: you need to crutch the intake. BMW S54 is a good example.

DON"T CRUCIFY ME OVER THE PREVIOUS STATEMENTS, obviously it's not necessarily that simple. It's merely meant as a conversation starter.

DISCUSS.

dl242gt 06-21-2022 03:42 PM

I had that restrictive efi intake tested when my cylinder head was modified. The efi intake took a large amount of flow away from the intake flow. After reading your post it makes sense to me that the exhaust with the 38mm valve didn't show as much improvement as I expected. I had a 405 head improved with stock valves and the 531 head got the 38mm exhaust with the same flow work. I forget the numbers but it wasn't that much more flow. It's in the spreadsheet that Gary made up.

Edit:That home brew flow bench is neat. Nice work!

122power 06-21-2022 04:42 PM

Can you expand on the exh valve shrouding comment? Said it flows same but then say it flows more?
So a stock exh port flows same as a bowl worked one, but deshrouding it made all the difference i take it?

redblockpowered 06-21-2022 04:54 PM

Affirmative. And a bigger valve in the same chamber is even more shrouded.

shoestring 06-21-2022 05:04 PM

Sure. I've had both a completely stock 530 head and then the above head professionally flowed. Same shop, same machine. The above head has an oversized 38mm exhaust valve as compared to the stock 35mm, with corresponding throat and bowl work done under the 38mm valve to take advantage. These heads have nearly identical exhaust port flow numbers, within a couple cfm at each point.

So what does that tell us? It says that the valve and throat area aren't the restriction. If you look at a picture of the combustion chamber of a 530 head, the chamber walls wrap pretty tightly around the exhaust valve for a good portion of its diameter. The only direction the exhaust gases can really get out is from the inside of the chamber. With the larger valve, the problem actually gets worse because because the diameter of the valve is closer to the walls of the combustion chamber.

We've observed that even on a stock head, no valve job, no port work under the valve, nothing, that exhaust flow improves SIGNIFICANTLY if you deshroud the valve: expose more of the diameter of the valve seat to escaping exhaust gases. Obviously, you can't go all the way around, but you can probably double the available area. Please don't read that as doubling flow.

My thought is that when we deshroud the valve, exhaust flow is going to jump a bunch. Like a Brady Bunch.

This is why I test and measure. I learned a long time ago that just because I did something doesn't mean I made it better.

Harlard 06-21-2022 05:57 PM

I like this. Looking forward to moar testing.

122power 06-21-2022 06:24 PM

Plus with a bigger valve you lose velocity and need to gain a lot of flow to get better or break even per se. Ive used a flow bench and once you use one you kinda dont wanna port anything without one after knowing what you find out. I need to make a homeade one though. What were your thoughts on the flow performance one?

MikeSr. 06-21-2022 07:02 PM

I’ve always wondered why, when this method only infers flow by measuring pressure drop- why doesn’t someone adapt an AMM to directly measure airflow

shoestring 06-21-2022 10:23 PM

Quote:

Originally Posted by 122power (Post 6271934)
What were your thoughts on the flow performance one?

It's more than the 14.99 I spent building this one? Honestly if I were to get to the point where I was really trying to port heads rather than just kind of a "let's see if this actually works" thing, it would be in the budget.

shoestring 06-21-2022 10:25 PM

Quote:

Originally Posted by MikeSr. (Post 6271948)
I’ve always wondered why, when this method only infers flow by measuring pressure drop- why doesn’t someone adapt an AMM to directly measure airflow

This is a wicked idea, but you would have to know the exact relationship of air mass to voltage, which I do not. Maybe Cam does.

redblockpowered 06-22-2022 12:28 AM

I have a TON of pictures of all this. Let's start with the bench itself:

We start by drawing air through the side of the "bore", like this:

https://i.imgur.com/nOWjekJl.jpg

This is PVC pipe with a tube epoxied in and a cap on the bottom held in with caulk.

Along with a wooden head mounting structure, like so:

https://i.imgur.com/nfE93fVl.jpg

A foam head gasket type thing completes the package:

https://i.imgur.com/pEDVlwVl.jpg

Along with a 96mm bore adapter 3D printed by my friend Zack:

https://i.imgur.com/VUvLyUKl.jpg

Valve control is handled by a screw on the stem of the valve, which is installed with a test valve spring, like so:

https://i.imgur.com/DB8ZZAml.jpg

The initial version measures pressure drop through the spark plug hole with the hose from a compression tester threaded in. To my surprise this does not leak.
The complete apparatus, V1:

https://i.imgur.com/C1DLK05l.jpg

There are some issues with the first version. There are a few small leaks which were easy to sort out. Most importantly, correlation is awful, the flow seems to hit a hard cut around .250" lift which doesn't match any big boy flow test of any 530 intake port I have ever seen. We made a few revisions before figuring it out.

First, the hose adapter was eliminated and the tubing was smushed directly into the spark plug hole:

https://i.imgur.com/ILLXYxPl.jpg

This seemed to do nothing at all at first. So we figured there was some quirk to drawing air from the side of the "bore" and carried on cutting a hole in the bench. This was confirmed by a test wherein the head was flipped on the wooden board and flowed more air in one orientation than the other.

Bench access hole:

https://i.imgur.com/brRcSe2l.jpg

So the vacuum could move air from the bottom:

https://i.imgur.com/tdIgbbal.jpg

A typical V1 flow test showing stalling far before an as-cast port is done gaining flow:

https://i.imgur.com/50DwhlHl.jpg

The unit is inches of water, but it's indicated inches of water on the hanging manometer so the actual water column height is given by 2*41-X where X is the number I have written down here. Very straight forward.

During another test while we were feeling annoyed by our lack of progress I decided to just keep jamming the tube into the bore. The result? More flow!

We ended up repurposing the tube in the side as a sort of "pressure chamber", where the manometer inlet now lives. It seems that the previous location was too turbulent for proper measurement of airflow in the port. Correlation much better now.

Stiggy Pop 06-22-2022 03:33 PM

that definitely looks like a basement in Swampscott (said affectionately)

shoestring 06-22-2022 03:45 PM

Quote:

Originally Posted by Stiggy Pop (Post 6272100)
that definitely looks like a basement in Swampscott (said affectionately)

Oh man is it ever

Harlard 06-22-2022 04:24 PM

Massachusetts joke noted.

bobxyz 06-22-2022 06:38 PM

Cool project! May it provide many hours of entertainment and head scratching. :lol:

Quote:

Originally Posted by shoestring (Post 6271989)
Quote:

Originally Posted by MikeSr. (Post 6271948)
I’ve always wondered why, when this method only infers flow by measuring pressure drop- why doesn’t someone adapt an AMM to directly measure airflow

This is a wicked idea, but you would have to know the exact relationship of air mass to voltage, which I do not. Maybe Cam does.

There are some sparse Bosch AMM (aka MAF) datasheets at: https://ipdown.net/documents.html

redblockpowered 06-22-2022 08:10 PM

It's been an incredible distraction so far.

edit: And the basement's just as damp as you'd imagine.

Swedbrick 06-23-2022 07:55 AM

I might need to build one of those with a MAF for the new garage, after I finish my other 10 projects that is:-P

As for the porting, I collected this in my 530 porting folder and always wondered how this could be one of the better flowing heads. Any future plans to also test intake valve sizes?
https://i.imgur.com/vMoAqtql.jpg

shoestring 06-23-2022 12:41 PM

Quote:

Originally Posted by Swedbrick (Post 6272191)
Any future plans to also test intake valve sizes?
https://i.imgur.com/vMoAqtql.jpg

Dude I wish I could tell you that we have the means to do that. Unfortunately we would have to send the head out to have that done. It's now extremely clear to me that it's the intake side, not the exhaust, that needs all the help it can get, because of the manifold.

It looks like KG Trimning offers an intake valve with a reduced stem size (from the picture). Anybody know about/have experience with this or something similar?

I'm also going to look into a flap wheel on a flexible shaft to see what can be done with these intake runners in the manifold. Where it's a dry intake I'm hoping I can pick up a little something if I make them smooooottttthhhhhhh....

I don't know. I do know that I'm kinda reinventing the wheel here and none of this will surprise most people.

Harlard 06-23-2022 01:07 PM

You could just ditch the stock intake manifold. You could have a port that moves 400 CFM; it’s still going to suck through a straw.

culberro 06-23-2022 01:33 PM

Quote:

Originally Posted by shoestring (Post 6272246)
Dude I wish I could tell you that we have the means to do that. Unfortunately we would have to send the head out to have that done. It's now extremely clear to me that it's the intake side, not the exhaust, that needs all the help it can get, because of the manifold.

It looks like KG Trimning offers an intake valve with a reduced stem size (from the picture). Anybody know about/have experience with this or something similar?

I'm also going to look into a flap wheel on a flexible shaft to see what can be done with these intake runners in the manifold. Where it's a dry intake I'm hoping I can pick up a little something if I make them smooooottttthhhhhhh....

I don't know. I do know that I'm kinda reinventing the wheel here and none of this will surprise most people.

From a strength perspective, there shouldn't be any issues with the undercut valves (reduced stem). I've ran ~52mm diameter valves with 8mm/6.5mm stems at a lot of revs without issues (pushrod V8). They can help with flow, or they can hurt... but you've got the tool to figure that out!

If you need to get deep inside the intake, a 6" long extended shaft burr is the way to go. I'll send you some links for some reasonably priced ones. They can easily get out of control, but with practice and brown shorts you'll get the hang of them. I also have a bunch of extended sanding mandrels as well, very helpful!

But really I'd look at another intake manifold, unless you're realllllly working on a budget.

shoestring 06-23-2022 02:04 PM

If I had tig skills and a tig, this would be a done deal. Also, the projects we have going now require OE reliability: Cam's got to be able to drive his 944 daily, and my buddy's 244 has to have probably 4-5 days a week out of it, 3 seasons, and be able to go a couple hundred miles from home without a hitch. That means that ALL the stuff that goes along with the performance aspect has to be bulletproof. You could almost say that the performance aspect is among the last things to consider. Sounds goofy, I know, but it's self-imposed restrictions like this that force us to think harder. When I was a kid we had cars that had wires running everywhere and exhaust leaks and stuff like that, but we had time to mess with them all the time and never went more than 30 miles from the house.

Harlard 06-23-2022 02:09 PM

The Swedes have zero complaints about these: https://shop.klracing.se/sv/artiklar...m-spjall-.html

shoestring 06-23-2022 02:24 PM

We might have an appropriate application for this.

culberro 06-23-2022 02:27 PM

I'm not sure what you have for a welder, but you can do decent work with a spool gun and a mig with aluminum. It definitely takes practice, but it's a much lower barrier to enter with.

There's not a lot of material in the stock b230f intake runners, and the injector boss area is a big (the biggest?) restriction there. Even the cheap welded KL Racing intake is 2mm larger in diameter at the port flange (40.5mm vs 38.5mm with the intakes I have here).

redblockpowered 06-23-2022 02:46 PM

Intake manifold swap seems outside of the scope of this (my) project. I like the cast KL one, the work and expense required is probably not worthwhile at this power level.

Depends on how in the weeds a ported B230F manifold still is, I suppose.

Either way you still have a Volvo 8V head.

Harlard 06-23-2022 03:05 PM

Just for what it's worth, your power ceiling without a turbo will be about 160 whp.

I'm assuming this is NA for some reason.

redblockpowered 06-23-2022 03:13 PM

There are a few project cars this here flowbench research applies to, one of which is NA.

My 940 - this is just my normal car that I use to get places
Racecar - for lemons racing
Dad's friend's 244 - fast weekend car

Different solutions make sense for each.

culberro 06-23-2022 04:32 PM

Quote:

Originally Posted by redblockpowered (Post 6272287)
Intake manifold swap seems outside of the scope of this (my) project. I like the cast KL one, the work and expense required is probably not worthwhile at this power level.

Depends on how in the weeds a ported B230F manifold still is, I suppose.

Either way you still have a Volvo 8V head.

So klr142s General Leif makes like 155whp (so assuming about 180 crank) with a modified k-jet intake (bigger tb, and some smoothing I believe).

That same engine, head, and camshaft combo will usually make 220 crank hp with ITBs or DCOEs. So that's a significant amount of power on the table with just the induction side.

A well warmed over 8v head can still do 260+ crank hp...

shoestring 06-23-2022 06:07 PM

Quote:

Originally Posted by culberro (Post 6272285)
I'm not sure what you have for a welder, but you can do decent work with a spool gun and a mig with aluminum. It definitely takes practice, but it's a much lower barrier to enter with.

We've got a Miller 211, so that's not the bottleneck.

culberro 06-23-2022 06:12 PM

Quote:

Originally Posted by shoestring (Post 6272338)
We've got a Miller 211, so that's not the bottleneck.

Zap zap

redblockpowered 06-23-2022 06:49 PM

My project = my car. Oops. Highly doubt I'll be touching 160 whp suction engine power (as they say) in the 940. In addition, welded up modded B230 intake is much less objectionable on a race car.

Harlard 06-23-2022 11:49 PM

Do as you wish, but bothering with that intake manifold is an abject waste of time and consumables.

Swedbrick 06-24-2022 10:34 AM

Quote:

Originally Posted by shoestring (Post 6272246)
Dude I wish I could tell you that we have the means to do that. Unfortunately we would have to send the head out to have that done. It's now extremely clear to me that it's the intake side, not the exhaust, that needs all the help it can get, because of the manifold.

I'd think you'd be able to spend some time there with a dremel continously checking as you go to get it done. The big problem would be the new pistons you need to get it to work.

As for the intake barring finding a suitable 2.0-2.5L stock manifold from another brand, the b21f setup appears to be the way to go.

crogthomas 06-24-2022 04:09 PM

Interesting stuff. Nice job.
I built my own flow bench a few years ago too. What surprised me is that it was really simple to do and it can be really accurate too. You've done the hard work. All you would need to do to measure actual flow rates is add a orifice of a known size between the head and the vacuum source with another manometer across it. You can either calculate the flow rate of the orifice, or get it measured on a known bench, then every pressure drop you measure across your head can be related to that orifice using a simple equation.
An AMM is a nice idea, but really difficult to calibrate. Manometers are very accurate. They are what would be used in a lab to calibrate flow devices anyway, so they only lose out in terms of user friendliness.

I think you did the right thing to reposition the manometer to the bore adaptor. The spark plug hole will be experiencing air flow across it, but you really need the manometer to be in relatively still air, to measure the pressure drop across the head as a whole. The larger you can make the chamber immediately under the bore adaptor the better. I used a 1m length of 4" soil pipe which seemed work well, but a large diameter drum of some sort would be better.

I can back up your findings about inlet manifolds. On a B230 530 head at 12mm valve lift I got about 138 CFM@28"H2O with a plasticine flow smoother on the inlet to give the best case scenario for that type of head. With the standard B230 inlet manifold added on that dropped to 120 CFM@28"H2O.

redblockpowered 10-06-2022 01:11 AM

Quote:

Originally Posted by Harlard (Post 6272381)
Do as you wish, but bothering with that intake manifold is an abject waste of time and consumables.

Here are the results of an abject waste of time and consumables:

First, the racecar head came back and we had a better way to calibrate the flow bench instead of assuming all the stock ports flowed the same. This revealed that all the prior numbers were fairly optimistic, which I believe because it all seemed a little too easy.

Next we flow tested the B230 and B21 manifolds on a stock port. No restriction noted for either.

What gives? Turns out it'd probably help if you plugged all the ports on the manifold...

After this our stock port and stock B230F manifold threw down these absolutely putrid numbers:

.050" 19.6
.100" 51.7
.150" 80.3
.200" 105.1
.250" 118.4
.300" 126.3
.350" 130.4
.400" 124.7
.450" 124.7
.500" 124.7
.550" 126.3
.600" 127.1

So, not much more flow than the exhaust port. Awesome.

Esmth donated this B230F manifold which got cut up and eventually ported in the name of science:

https://i.imgur.com/ebkpovIl.jpg

First thing to note is all the nasty bosses in the plenum area. Those got cut off and the runner entry got smoothed particularly on the short side. Cylinder 1 and cylinder 3 are especially impacted by the throttle body stud bosses, one of which was good for some 8 cfm at peak on its own (I forget which, I think #1)

https://i.imgur.com/b5Uq9ncl.jpg

The injector bosses on the B230F manifold can be slimmed down considerably although this made only a small difference in our tests.

https://i.imgur.com/UuIKh24l.jpg

The big ticket seemed to be in widening the runner near the port entry, particularly on the long side.

https://i.imgur.com/DPBtaVnl.jpg

Fortunately for me my dad took good notes of what the final product ended up being, in the name of repeatability:

https://i.imgur.com/3AHCGVCl.jpg

And I made this little tool, which you can have the STL file for if you ask nicely (or tell me where I should upload it):

https://i.imgur.com/rDX9N2Kl.jpg

The narrow end goes in the injector boss area once porting is complete, and the wide end goes into the widest part of the runner until the notch is no longer visible. Here it is, not going, plus the first few layers got too squashed:

https://i.imgur.com/UuIKh24l.jpg

and of course the final results, before and after:

.050" 20.4 20.8
.100" 50.7 51.2
.150" 79.1 79.7
.200" 103.0 104.4
.250" 120.7 121.5
.300" 134.6 135.5
.350" 144.4 147.1 +1.9% (gainz not worth noting up to this point)
.400" 147.1 154.7 +5.2%
.450" 149.0 160.7 +7.8%
.500" 149.9 163.7 +9.2%
.550" 149.9 157.7 +5.2%
.600" 150.9 157.7 +4.5%

redblockpowered 10-06-2022 01:30 AM

Oh, and the port with no manifold:

.050" 21.6
.100" 53.7
.150" 84.6
.200" 112.4
.250" 135.5
.300" 152.8
.350" 166.9
.400" 166.9
.450" 166.9
.500" 171.1
.550" 173.3
.600" 175.5

The smart folks on speed-talk.com seem to suggest an expected loss of around 1% per tenth of an inch of valve lift with the intake system installed no matter what. We didn't test the B21 manifold on this port but on a stock port it came in around a 10% loss at worst. Significant improvement over the B230 manifold

Also worth reading:
https://www.motortrend.com/how-to/hr...ifold-porting/

Harlard 10-06-2022 04:40 AM

Glad you’re generating data-backed insights on the topic! Genuinely interesting couple of posts.

Still sticking to my hot take on the B230 manifold being poo, however :-P

linuxman51 10-06-2022 12:10 PM

cool!

esmth 10-06-2022 12:15 PM

If I am reading this right, there doesn't seem to be much of a benefit porting the manifold with any of the stock smaller cams below like 10.5mm intake lift? M, T, A, B?

Harlard 10-06-2022 12:35 PM

Quote:

Originally Posted by esmth (Post 6290405)
If I am reading this right, there doesn't seem to be much of a benefit porting the manifold with any of the stock smaller cams below like 10.5mm intake lift? M, T, A, B?

My conclusion here is: if you have to keep it, porting it does not hurt at all.

shoestring 10-06-2022 12:39 PM

Quote:

Originally Posted by Harlard (Post 6290333)
Still sticking to my hot take on the B230 manifold being poo, however :-P

And you would be correct.

redblockpowered 10-06-2022 01:01 PM

I was impressed with the results of the turd polishing effort.

shoestring 10-06-2022 01:15 PM

Quote:

Originally Posted by redblockpowered (Post 6290314)
and of course the final results, before and after:

.050" 20.4 20.8
.100" 50.7 51.2
.150" 79.1 79.7
.200" 103.0 104.4
.250" 120.7 121.5
.300" 134.6 135.5
.350" 144.4 147.1 +1.9% (gainz not worth noting up to this point)
.400" 147.1 154.7 +5.2%
.450" 149.0 160.7 +7.8%
.500" 149.9 163.7 +9.2%
.550" 149.9 157.7 +5.2%
.600" 150.9 157.7 +4.5%

For clarification, these are the final results on the prepared head, not the stock one. They also include a couple of changes we made after we were able to flowbench the entire intake system, some of which were significant in their own right. It's Cam's thread so I'll let him tell you what we did.

What I got out of this is a couple of things:

First is that when Volvo made the...performance? variant B230FX, they knew the intake was doodoo for this purpose knew the cam would need to crutch the intake. Hence the infamous VX, with the V intake lobe and smaller X exhaust lobe. I asked my machinist (R&L Engines in Dover, NH) about the 75% exhaust to intake flow relationship (Google it if you're unaware). There's lots of internet conflict on this and while it makes sense to me, what do I know? Anyway, I asked if was a real thing and was assured that it absolutely is a real GUIDELINE, not necessarily a rule.

Second is that air is heavy and hates to turn corners, wherever they are. Wherever you can help it through port efficiency rather than port volume will help.

Finally, when you're REALLY TRYING HARD to improve performance, you really need to pull yourself back and see the package as a whole, from where air first enters your influence to when it returns to atmosphere. It's easy to look at it as a combination of individual pieces, but that might not get you the best result.

In short it took us probably 6 months to figure out that we could get about a 20% improvement in the intake system. Knowing what we know now, I took this opportunity to order a custom cam from Jones Cams in Denver for this engine. We'll let you know how that goes...next Summer.

culberro 10-06-2022 01:47 PM

Quote:

Originally Posted by redblockpowered (Post 6290415)
I was impressed with the results of the turd polishing effort.

And you should be! I think you're developing a well balanced system.

Quote:

Originally Posted by shoestring (Post 6290417)
In short it took us probably 6 months to figure out that we could get about a 20% improvement in the intake system. Knowing what we know now, I took this opportunity to order a custom cam from Jones Cams in Denver for this engine. We'll let you know how that goes...next Summer.

And a 20% increase is SOLID as a system. When I port a head and then someone says they're using the stock manifold I just ask "then why am I porting the head????"

That cam should be a very nice setup for you. I don't know how aggressive the ramps are, but I hope you're getting something that's less pointy than a VX :)


All times are GMT -4. The time now is 08:30 PM.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2022, vBulletin Solutions Inc.