1g plenum power port results

[hypo23]

finally got my plenum back the other day after being power ported. thanx to andrew from specialised power porting, he says its the best flowing 1g intake hes seen which was a bit of a surprise as no real thought went into its design, i just mainly wanted the throttle body at the front, for neatness under the bonet. (see pics below)
any way heres some before and after result.

before and after
1, 279cfm 327cfm up 48cfm
2, 276cfm 325cfm up 49cfm
3, 302cfm 338cfm up 36cfm
4, 302cfm 340cfm up 38cfm
5, 298cfm 341cfm up 43cfm
6, 299cfm 339cfm up 40cfm


variations in the befores was 26cfm and in the afters is 16cfm, i would of thought it would bring the diffences a bit closer but andrew assured me its a pretty good result, especially with an average increase of 42.3 cfm per runner which he was pretty surprised at.
now its a matter of getting the head right, which is off getting done atm, and andrew and a couple of other guys have given me a few ideas as too keeping the water in the head i bit cooler and a more even temperature, which is something i want too have a bit of a play with as its another problem 1gs have when you start too lean on them too hard.

anyway hope this is some interesting use for some of you with 1gs, full results wont be realised untill we can get it on a dyno, in a couple of months time, hopefully before the toy nats although the main aim isnt outright power atm rather than reliability, as pulling the motor out of the celica is something im sick to death of

[emp?]

nice
what kind of $$$ was that? i should go get mine done

[Hydra]

Very nice mate, Something i'd like to do someday!

[hypo23]

josh, would be interesting to get yours done, as a fair few people have a very similar designed one too yours, it seems to be a very popular design.
price was $660 which included him fixing a couple of pin hole leaks and remachining the face of the manifold straight, it is pretty dear but if it helps me stop braking engines its worth every cent, and thats breaking them at no where near the power that josh is making.

[YelloRolla]

nice work Steve. +1

[ndgcpr]

is it only as good as the lowest flowing one?

Like if you maxed it out would the different flows pose a problem?

[JustCallMeOrlando]

is it only as good as the lowest flowing one?

Like if you maxed it out would the different flows pose a problem?

Yes. If you maxxed it out though, it wouldn't be with a 1G head. It doesn't flow anywhere near as much as the manifold itself, especially now.

Looks good mate, bit pricey, but then what price do you put on reliability?

[emp?]

well i might get this done me thinks, im going onto my 3rd motor and getting over changing them, tho the 2nd motor had issues even before it went in the car...
what are the details of the shop?

[hypo23]

as i said josh would be interesting to see your results, contact details are as follows;
specialised power porting phone andrew sanders (03)53301123 or 0438418028

andrews a good bloke to talk too and a wealth of knowledge he has done quite a few 1gs before and would recommend him to anyone

[YelloRolla]

is it only as good as the lowest flowing one?

Like if you maxed it out would the different flows pose a problem?

I wouldn't think so. Different cylinders will always make different power to each other; some engines are designed that way, even if by bad design and space necessity.

If one flowed abnormally more than the others then it could run lean = bad (maybe JCMF referring to this?); but this is not that likely as the flow bench is done without consideration of closed valves and a greater working pressure.

[Grega]

nice one - especially like the flow figures man good job.
be interested to know what a difference it makes in drivability ect.

[JustCallMeOrlando]

If one flowed abnormally more than the others then it could run lean = bad (maybe JCMF referring to this?); but this is not that likely as the flow bench is done without consideration of closed valves and a greater working pressure.

Something to that effect, part of our discussions on the topic point to people having problems where one cylinder flows more than the others and subsequently dies This power porting is a partial solution to the problem.

[YelloRolla]

aahhh I see, where before I was blind.

[Joshstix]

This process is pretty popular with the US 3S guys as the stock manifold seriously favours the middle two runners. Apparently power porting or Extrude honing which they use in the US really helps even out the flow runner to runner.

As to whether the engine will be limmitted by the lowest flowing port that depends on how it's tuned. In theory if the time was spent to tune the individual cylinders then you should be able to maximise the output of each cylinder, this is rather cost and time prohibitive though.

I agree with Jase +rep for showing the community something that isn't overly common around these parts.

[mic*]

The oxygen sensor reports the exhaust from all cylinders, as does the MAF/MAP sensor for intake flow so fueling is kinda an average of all cylinders rather than limited by the lowest.

If a cylinder/s flow grossly more than the average they will run lean.

Since on this manifold 4 out of 6 runners run approximately the same flow, which is higher than the other two (richer cylinders, assuming each port on the head flows more or less evenly), i think it appears to be quite a good design.


Hypo23,

Is that a standard 1G intake plenum (less TVIS) & a 1G throttle body - ie the custom part being the phat log in between?