202ci intake manifold ideas

[steve cowan]

a new side project
200ci inline 6 with 12port head and intake manifold.
Looking for feedback if this intake/plenum idea will work,carbs undecided so can adapt 2 x 2 barrel carbs or 2 x 4 barrel holleys.
The end game is around 450 hp with progressive nitrous fogger,car will be geared and converters as required wanting peak around 7000rpm
Thanks in advance.

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[SpeierRacingHeads]

Here is what I put on a 202" 4-cylinder. Book dominator also.

[mt-engines]

a new side project
200ci inline 6 with 12port head and intake manifold.
Looking for feedback if this intake/plenum idea will work,carbs undecided so can adapt 2 x 2 barrel carbs or 2 x 4 barrel holleys.
The end game is around 450 hp with progressive nitrous fogger,car will be geared and converters as required wanting peak around 7000rpm
Thanks in advance.20200924_082829.jpg20200924_082739.jpg20200924_082732.jpg20200924_082712.jpg20200924_082656.jpg

my vote is for 6 44mm Mikuni

[BLSTIC]

There's a reason Holden went to RB engines :p

But really I'd go 2x4 in a spreadbore format, even if it is just a drag car you'll appreciate the tiny primaries being able to move the car at less than full throttle. Sounds like you won't need much airflow though.

Does your class ban efi?

[steve cowan]

Here is what I put on a 202" 4-cylinder. Book dominator also.

Chad,
Is that a Bonneville car ??
Must turn some rpm

[steve cowan]

a new side project
200ci inline 6 with 12port head and intake manifold.
Looking for feedback if this intake/plenum idea will work,carbs undecided so can adapt 2 x 2 barrel carbs or 2 x 4 barrel holleys.
The end game is around 450 hp with progressive nitrous fogger,car will be geared and converters as required wanting peak around 7000rpm
Thanks in advance.20200924_082829.jpg20200924_082739.jpg20200924_082732.jpg20200924_082712.jpg20200924_082656.jpg

my vote is for 6 44mm Mikuni

I had to google for a look,would be pretty neat idea

[steve cowan]

There's a reason Holden went to RB engines :p

But really I'd go 2x4 in a spreadbore format, even if it is just a drag car you'll appreciate the tiny primaries being able to move the car at less than full throttle. Sounds like you won't need much airflow though.

Does your class ban efi?

no class just some fun,i have a couple friends that run holden 6 cylinder stuff with nitrous and I am a SBC guy so I feel left out
My car is 1000 pounds heavier as well but I want to give the boys a run for there money and do something different, 500hp will put me in 10.9s- 11.0s area which would be fun,I want to run the holley carbs because that's what I am familiar with, I am spending money on good pistons rods etc,playing around with cast iron head and will upgrade to Australian made aluminium head if i can see some potential in induction system. The biggest challenge will be a automatic trans that will handle it,not sure if a power glide will work and the 6 cylinder trimatic could possibly fail or be a issue at least.

[BLSTIC]

I've seen a v8 Trimatic run 10.8 behind a 383 in a not stripped VC, so those can handle the punishment if built.

There's also the Duggan or Jzed head for that motor. Much more downdraft port.

What car are you running it in?

PS if there's no rules it would be killer to see a turbo efi Holden six do a 10 second pass... More work than carb and nitrous for the same power though. I've seen a 200-250hp suck through one though so there's hope (real simple recipe, stock 202, Strata turbo kit, 650 Holley, avgas, held together at 20psi, but that might be because the loose seat in the LC Torana made us pack ourselves and back off before it could be loaded for too long)

[F-BIRD'88]

Consider using 2x 650 AVS2 carbs sideways on a modded version plenum.. You may find usefull stuff from available Holley HIRam plenum (top/ bottom) parts instead of cutting and pasteing that Weiand plenum. Interesting.

Carbs could be mounted sideways or inline.
With Three intake ports inline under each carb it really doesn't matter.

[steve cowan]

I've seen a v8 Trimatic run 10.8 behind a 383 in a not stripped VC, so those can handle the punishment if built.

There's also the Duggan or Jzed head for that motor. Much more downdraft port.

What car are you running it in?

PS if there's no rules it would be killer to see a turbo efi Holden six do a 10 second pass... More work than carb and nitrous for the same power though. I've seen a 200-250hp suck through one though so there's hope (real simple recipe, stock 202, Strata turbo kit, 650 Holley, avgas, held together at 20psi, but that might be because the loose seat in the LC Torana made us pack ourselves and back off before it could be loaded for too long)

A friend has one of the original duggens from Max carpenters super stock torana from back in the day,
My car is a HQ ute styleside that was originally a 6 banger 3 on the tree deal,its been SBC set up for over ten years now so I figured it will bolt in easy as I have the car set up. Eventually I will put it friends LJ torana after I sort it all out.
I done some measurements today and cc one runner and was told by reliable source that intake is to small unfortunately.
2.31" CSA at top of runner,
1.24" CSA at flange
I measured port centreline at 14"
Cc one runner at 382cc
So avg csa is 1.66" approx.
So i worked out i need intake port avg csa of 1.75" for peak of approx 7000rpm
Avg velocity of 322 ft/sec
Cfm demand of 235cfm at max piston speed
Port vol of approx 108cc
Port length 3.78"
206ci
3.665" x 3.25" stroke.
I have not done any work on a 6 cylinder 12 port head so all those numbers i put up might not be realistic, we will see i spose.
I will cut and shut the intake manifold around head flange area and back about 4"-5" to open the cross section but could be a fail but want to try first.

[blown265]

G'day Steve
I'd prefer the six motorcycle carbs simply for clean fuel distribution with that manifold- I can't see a plenum/adaptor on each of those individual runner groups working well without significant internal development.
I could be wrong, but I know that the choice of 4bbl manifolds on our I6 265ci can make or break the end result, simply depending on how good the transition/distribution is. (and when I say 'break', I mean that literally too- end cylinders not getting fuel etc)
The bike carbs are very simple to tune, and certainly have a distinctive character and appeal. I know of a 265 that used a brace of six Mikunis more than 30years ago, so it can be done.
Regards
Paul

[BLSTIC]

What's your goal power wise without nitrous? That will determine your intake csa more than anything. A well developed 202ci engine at 7000rpm is going to be making north of 300hp by itself, making that amongst the most powerful Holden 6's ever built

[RT Machine]

Sidedraft Webers are pretty hard to beat for tuneability and fuel distribution right ? especially on a Holden 6.
Is the setup more about the look ? Don,t get me wrong - different is great !

[steve cowan]

What's your goal power wise without nitrous? That will determine your intake csa more than anything. A well developed 202ci engine at 7000rpm is going to be making north of 300hp by itself, making that amongst the most powerful Holden 6's ever built

I would like to think around 280 is realistic,
I took my father and I to the roundy round track today and I talked to some 6 cylinder guys,all running 9 port heads,roller cams ,triple Webber's etc some guys were saying 260 at the wheels is pretty common apparently.
Triple carbs are the most popular, got a mate who runs a 465cfm holley 4 barrel and a single plate system, runs 10.9s at 118 full weight LC torana streeter on radials. He spraying 175shot.

[steve cowan]

Sidedraft Webers are pretty hard to beat for tuneability and fuel distribution right ? especially on a Holden 6.
Is the setup more about the look ? Don,t get me wrong - different is great !

Mainly something different, I think once I start working a test head and flow test with intake bolted on the head it will show results,my expectations are not high on that intake but gotta prove it to myself even though I know there are some experienced guys on speedtalk that know better than me