1G head flow numbers and intake designs...long

[JET]

You are forgetting one thing. If you get more peak torque at a higher RPM, it is still better. You can always run shorter gears, which will give you more torque to the ground. The bad part about higher RPM is that our cars don't like to shift above 9k and you must have a worked tranny to shift decent above 8k. As you guys may not know, we do have stroker versions of our engines, 2.34l. They have been around for many years, but have not caught on real well. Some people do run them, but they are that much harder on the drivetrain from all the extra torque.

 

[fiveliterfrenzy]

Oh that's right, i forgot about the fragile nature of most AWD systems. Well, you could do what a guy i know in Cali did to his 3kGT and just flip that motor front and center, and feed the power through a porsche 928 GTS transaxle.

 

[snox135]

Originally posted by Polk
OK everybody, I have some more flow data on the 1G head. Now this one is pretty much a race ported head. I will start off with everything that was done with the stock one has been done here as well. Example: ¾” radius entry. #3 intake runner and so on. All tested @ 28” of water

Now I want everyone to realize one thing…..WE ARE NOT RACING FLOW-BENCHES…. The numbers that I am posting just show the characteristics of different manifolds and how they react in different applications. Just because this intake shows to outdo another does not mean that it will be right with your combination. Many of DSMers have ran good times with stock intakes. Marco at Magnus ran a very low ten second pass with a stock head. But one thing you have to remember.. Efficiency means power.


4G63 level 4 head. 1mm over valves, no intake, ¾ radius entry

Lift CFM
.050 60.38
.100 106.30
.150 161.19
.200 187.97
.250 241.11
.300 270.10
.350 298.19
.400 309.45
.450 320.31
Now I kept on flowing it past this lift to just see what this thing could do.
.500 334.25
.550 345.98
.600 357.32
.650 365.21
.700 374.46 Now that should give some of the V8 guys nightmares.



Same head with 4” tapered runner 240 cubic inch plenum
Lift CFM
.050 58.46
.100 101.35
.150 147.94
.200 210.84
.250 226.48
.300 259.33
.350 282.48
.400 298.19
.450 307.60

How did the 4" tapered runner 240 cubic " plenum flow more than no intake at .200 lift?

 

[JayHass]

Originally posted by snox135
How did the 4" tapered runner 240 cubic " plenum flow more than no intake at .200 lift?

Probably a resonance effect. Much like a CAI on a NA car.

 

[Guerillah]

This info is off the mr2 board. There is a lot of controversy on the the mr2 board right now with runner size hurting power if sized too large which the quy in the quote below thinks they all are. What do some of you guys who design intake manifolds think of what he said (Polk, etc..)?

quote:
--------------------------------------------------------------------------------
Originally posted by Takumi
dginter001- What would be the optimal mainfold for the 300-350 hp range 3SGTE, in your opinion?
--------------------------------------------------------------------------------

It depends on valve diameter, cam duration and turbo size but I'll make some assumtions based on some popular combinations.

Runner Area

First of all, the runner *area* is largely a function of the valve area. For a relatively stock cylinder head with stock intake valves (33.5mm), I would say that 80 percent of valve area would be a good target.

With 33.5mm, we have an area of (pi*r^2):

pi*(33.5/2)^2 = 881.4mm^2

But we have two valves, so 881.4 x 2 = 1762.8mm^2

Take 80 percent and we come up to 1410.3mm^2

If we want to find a round pipe diameter, we have to go backwards through pi*r^2...

2*sqrt(1410.3/pi) = 42.4mm

This is slightly more than 1-5/8" of inner diameter (the pipe OD will definitely be larger). For reference, the Trueleo manifold has 2.5" runners which probably function like a manifold with a runner length of zero (i.e. - they are plenums that bolt to the head).

If the runner has to be curved, then it would probably be safe to run 1-3/4" runners. Ideally, it would probably be best to have a straight runner of 1-7/8" at the plenum while tapering to 1-5/8" at the port. Tapered runners have shown a noticeable gain over the conventional straight runner and are finally making their way into production cars.

Go slightly larger for an optimized port with oversized valves...

Runner Length

The runner length affects the RPM at which the tuning peak is most effective. In most cases, the runner length is tuned to coincide with the engine's natural torque peak because the tuning is most effective at this point. Sometimes the runners are tuned to peak elsewhere in order to flatten things out.

The rule of thumb is to use 7 inches @ 10,000rpm (from the back of the valve to the plenum) and add 1.7 inches for each 1000rpm below this (or subtract for above). So for a 3SGTE, a manifold tuned for the engine's natural torque peak around 5krpm will yield a runner length of 15.5". Getting more aggressive would probably bring this down to the 10" - 14" range. These numbers include the length to the back of the valve so the actual manifold would be a couple inches (EDIT: a few inches) shorter.

...

Darren


Last edited by dginter001 on April 23rd, 2003 at 04:48 PM

 

[Polk]

Guys sorry for not updating this in a long time. We have been way too busy the past few months for me to do any research.

I do have a few other things in the works. As soon as we get a little caught up at the shop I will share some more info.

Thanks
Polk

 

[DaTurboTalon]

Originally posted by Motohead1


If i ever have the money somday I would like to adapt this to a SBC 383 (destroked 400)

I dont think any of you care but a 383 is typically a STROKED 350 using a 350 block and a 400 crank. This is probably one of the most popular motors around right now.

Although you can make a 383 by destroking a 400 with a 350 crank, and boring the 400 block .060 over which requires a EXPENCIVE block to do safely. So this 2nd type of 383 is very rare.

 

[Guerillah]

Here is a flow bench of a stock head off of a 2nd gen 3S-GTE (MR2).

You must be logged in to view this image or video.

 

[MNGSX]

Originally posted by DaTurboTalon


I dont think any of you care but a 383 is typically a STROKED 350 using a 350 block and a 400 crank. This is probably one of the most popular motors around right now.

Although you can make a 383 by destroking a 400 with a 350 crank, and boring the 400 block .060 over which requires a EXPENCIVE block to do safely. So this 2nd type of 383 is very rare.

The most common destroked 400 is a 377. Just a 350 crank in a 400 block. Depending on overbore you can hit 383 ci with it too.
It is still refered to as a 377 by most people even if bored a bit. That way people know what crank is in it.

 

[MNGSX]

Back to flow benhcing intakes.

What about runner angle?

Take plastic wedge shaped spacers and use them to alter the angle of the intake runner relative the intake port. Start at perpendicular work downward angle wise seeing if flow increases. Then flip the same spacers over to tilt it in the same graduations upward while benching it. 0 (perpendicular) - (down) + (up)... -15, -10, -5, 0, 5, 10, 15

There has to be a sweet spot for the runner angle.

 

[AWDBurn]

Originally posted by Motohead1


Honda will probly be the first they suposidly have a 1.5L motor with a CRV head and the main issew is seal longevity. Same problem everyone is having. But your right if big three would jump in it would have been here by now. Imagine spinning any engine upwards of 12,000+ rpm. O well i can dream.

If you want that high of RPMs, I would invest in a wankle engine. Rotary engines are fundamentally masterminded for high rpms.

 

[madnezpr51]

Great info on the flow numbers on the head ans the manifolds.

I was wondering if you could put the flow numbers for the exhaust port. stock 1G head and a ported head.

If its possible I would like it if its possible is just something I would want to know.....just curiosity!!!!

 

[turbo2litre.com]

I can't wait to see the stock 2g head flow numbers....

 

[Violater101]

Well, its been like 5 months since the last post ...not sure if we ever will see them posted

 

[na90dsm]

THREAD RESURECTION


Where are the 2G Head Flow Numbers

 

[lambertvr4]

I will talk to Polk next week about this. He should have my 2G head back from getting CNCed any time so he could flow that one. Not sure if he has a stocker laying around though.

 

[BOOSTIN21]

i think alot of people are going to be surprised with the flow of the 2g head, there should be a SMIM and 1g head vs. SMIM and 2g head. alot of you will be surprised. lets just say i bought a 2g head for my 1990 Tsi AWD

 

[kgtalon95]

2g head on a 90?? Please explain, is the extra power coming from the smaller ports, ie..air velocity. Most of us are in the dark here

 

[NDgsx]

Port shape and velocity. The 2G intake port will flow more air on the short side radius as the air doesn't come up over a hump before hitting the valve, it's a much more direct shot.

 

[lambertvr4]

I prefer to let Polk explain, but I'm building a 6-bolt for my 95 Talon and sticking with the 2G head for more than one reason. We'll see what the flow numbers have to say. Stock size valves, ported to the size of a 1G.

 

[kgtalon95]

wow, I didn't know that! I haven't even touched my internals yet, but i'm sure my day will come...after I get a degree and can feed my boost addiction

 

[gsx951]

I prefer to let Polk explain, but I'm building a 6-bolt for my 95 Talon and sticking with the 2G head for more than one reason. We'll see what the flow numbers have to say. Stock size valves, ported to the size of a 1G.

Better yet, the try the dyno because it shows you what a flow bench can't.
The flow bench is an interesting benchmark but it doesn't factor in velocity.

 

[BOOSTIN21]

Port shape and velocity. The 2G intake port will flow more air on the short side radius as the air doesn't come up over a hump before hitting the valve, it's a much more direct shot.

Exactly... See moxt people think that the 1g head flows more, well in an instance that is true, the reason for this are the more aggressive cams, intake manifold, and TB, but lets say you replaced these then on a 2g head, it would flow more. A 2g head with proper porting will outflow a 1g head with porting due to the port angle of the valve.

 

[NDgsx]

Yup, then if you really want to get serious and port it correctly take material off of the roof. Depending on how much you remove you may have to weld up the injector bosses and move the injectors back into the manifold runners.

 

[kgtalon95]

Anybody know were I can find a cheap 2g bare head??