tosh

Only @ stage3 so none of this is necessary! “But knowledge is good”

whilst cleaning & tidying up the outside of the inlet manifold/plenum got me thinking! Is there any benefit in polishing and deburring the internals, I don’t mean porting it out as I presume that’s matched to head ports etc I just mean improving air flow because as standard they are quite a rough casting.

I remember reading something ages ago about turbulence being good for even distribution of air! is that correct ?

My apologies as this sort of thing has probably been answered a thousand times but I can’t seem to find a definitive answer, and what information I have found needs translating into a language my simple brain can understand

costina

iTrader: (1)

Really makes no difference at that power level.
I am on a std 2wd intake on blacks with 421bhp.

Next upgrade would be a 4x4 intake plenum.

Caddyshack

I think people say that a spacer on the 4x4 inlet is a benefit but you may be better off with a hart inlet if you are going to look for more power later or have it mapped etc

tosh

That’s. What I’m putting on it, mainly for the reason that my original one had a cracked elbow bolt fixing and I had purchased the 4x4 one years ago.

I’m not chasing power I was just curious and wondering if there’s any benefits or detrimental effects ie: throttle response etc

tosh

Don’t you get more lag with a spacer at 300 to 350bhp

Caddyshack

Don't know

Mad_Mat

I don't think it would be measurable.. The extra volume added by a spacer would be filled in milliseconds.

The less restrictive the inlet the better. Anything to help the air flow on its way to the cylinder is a good thing imo.

I went Hart inlet on my stg3 and a bit and got good overall results.

costina

iTrader: (1)

Fit the 4x4 one and that will be fine for your power level.

tosh

So would there be no gains on a car that had already been live mapped after polishing not porting the internals of the inlet trumpets and plenum casing on a car running say 320 if it was then mapped again?

The same goes for addition of a spacer.

costina

iTrader: (1)

Any changes from a std set up would really require a live map.
For your power level it will have minimal if any benefit.
Yes if you want to spunk £££'s on a Hart inlet and have a remap on green it will produce more power BUT I have seen greens produce their max power on std intake manifolds.
Best money to spend on a cossie is a new loom and new sensors and if possible wasted spark and closed loop.
And most important is to have it set up correctly.....

Paul

tosh

All of th above Paul have already been purchased over the past few yrs with thanks to MSD’s New Years discount sale excluding W/S & C/L, with the addition of an Airtech 500 intercooler and all the other recommended upgrades which will be going on it when it’s back from the painters, and possibly treating myself to a T34!

So the reason they didn’t come from the factory polished then is down to not having any real benefits and also cost.

I’m guessing the early motorsport touring cars etc would of used an aftermarket plenum?

costina

iTrader: (1)

The touring cars used a std rs 500 intake with 8 injectors. No fancy polishing etc.

tosh

Been having a measure between the 2wd & 4x4 plenum today the 4x4 plenum is approximately 10mm deeper and granted the elbow is larger with smoother radiuses, but I would of thought they would of designed the slot a lot bigger where it enters the plenum as it is only 3mm wider and the same length, so this is still the restrictive point!

Just curious has anyone dyno’d before and after fitting the 4x4 plenum if so what were the gains?

Caddyshack

I expect you would begin to notice the difference where one begins to show its limit and the other does not and under 400bhp I doubt you would be near that envelope so both would flow enough not to show a big difference but you might not get last 500 bhp with one where the other would?

tosh

As mentioned I’m not going to go down the big BHP route so will never need to reach the upper limits of the standard parts, (excluding Injectors of course) it was more of a curiosity while I was changing to the 4x4 plenum “ knowledge is good “
Obviously Ford new the restrictions of the 2wd plenum so why should they go to all that expense of re-designing and tooling a new one to not really improve it that much? I’m sure the standard factory 4x4 would have worked just as well with the 2wd plenum.

costina

iTrader: (1)

The main reason would be cost due to the 2 piece design of the 2wd manifold.
So will all redesign design it better.

Same with the 200 block it was designed based on the 500 block and due to increased strength to accommodate the 4x4 system. There is a lot of weight bolted to the bottom.

Ford would not really done any modifications for power only reliability in service and cost.

tosh if you was aiming for over 400 and beyond I would say go for the Hart style inlet.

Paul

tosh

I’m only going greens with MSD L6 stage 3 chip so will realistically expect around 300 to 320 Paul so won’t be going anywhere near the 400 mark, might get it live mapped at a latter date.

makes sense what you say about manufacturing costs with the two part being more expensive to make I didn’t think of it that way.

I decided to do a internal volume test excluding the trumpets by filling them with water, “don’t know why as I can’t use the findings to give an intelligent answer” It might be of use to.

4x4 plenum held 2000ml
2wd plenum including elbow held 1850ml

So the 4x4 plenum is only 7.5% larger.

costina

iTrader: (1)

Any info is good. I did search myself and came up with nothing.
I used to run a 4x4 inlet on my last saff and tbh when I changed all the stuff over to my current saff I didnt feel any difference as I am using a 2wd inlet.

I have a AS inlet for my other car but as I have cams and a GT series turbo that will require a live map.

As Stu said on another post everything will play a part in how the engine responds etc so a live map.is the best solution if you can afford it.

My car runs a live map which Stu done for James as my spec was almost identical but my car has a tad more power due to the 2wd exhaust manifold and cutback blades on turbo.

Stu @ M Developments

iTrader: (12)

At your power level its wholly unecessaryim afraid Tosh.
The current flow limit on your engine is your T3 turbocharger. You are quite some way from the inlet tract being a problem yet.

tosh

As I mentioned earlier Stu I’m not chasing the high end of the 300’s the only reason I’ve put the 4x4 plenum on is that the old one was cracked and tatty. it was whilst cleaning the new one up got me thinking about the parameters of the plenum as it’s the first time I’ve taken it apart, which then opened the question in my mind as to why the castings were so rough internally hence all the above questions.

In fact Stu I probably will be going down the T34 route when I get the car back from paint so the 4x4 plenum might be beneficial, so will be giving you a call at a later date to upgrade the chip I purchased from you 3 yrs ago, which is still unused in it’s box, and also a full check & setup.

Stu @ M Developments

iTrader: (12)

The 4x4 plenums worth having anyway as it eliminates another air leak source. Just dont go mad porting it and cleaning it up.

Hope to see you one day soon mate.