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GarthW
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Re: Inlet Manifold Design

Post by GarthW »

Just bought a new fuel pump today, its rated to flow enough for 600Hp, so will be plenty for what i need. I'll be lucky to make 300hp lol..

As for the FPR, you wouldnt believe how much Bosch want for a rising rate reg-$800.00. :shock:

So getting an aftermarket one for around $150.

Hopefully thats comes quick from ebay so i can get it back on the dyno this Sat... :roll:

Then fingers crossed with those fitted she will make some decent power...h
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Mats
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Re: Inlet Manifold Design

Post by Mats »

I don't get it, you have a seriously modified engine but stock electronics?
If you have an aftermarket system you will only be adding complexity with a non-linear FPR. Just get a linear one that can handle the flow from the now huge pump.
If the injectors are too small, change them, not the FPR.
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Giuliettaevo2
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Re: Inlet Manifold Design

Post by Giuliettaevo2 »

If you start using a RRFPR now you need to map the enginemanagement completely again... All teh fuel maps will be off when boost arrives. :wink:

Listen to Mats and just use the bigger pump and fit bigger injectors if you're leaning out.
Drive it like you stole it...
la_strega_nera
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Re: Inlet Manifold Design

Post by la_strega_nera »

Still 1:1 Mats, some fprs don't up the pressure too well with boost.
the non 1:1s can just give you some more headroom in terms of marginal injector sizing - i guess it also gives you better resolution on the injector pulse width at low power settings
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GarthW
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Re: Inlet Manifold Design

Post by GarthW »

Mats-Stock electronics..? :roll:

Evo-I already have high flow injectors fitted. :) Yeah the engine map will have to be re-done.
But what has been bugging me is, when it was first dyno-tuned with the standard pump, and the manifolds i made, the car was f@#king flying, and that was on 8-10psi.
Now with the smaller manifolds i'm getting loads more response...but to me the car is now going backwards...maybe the fuel pump is starting to wear out..? The injectors are twice the volume of the original injectors so they should be ok.

When the car was on the dyno the other day, we blanked off the return line from the FPR to the fuel tank and it gave more fuel, not enough but more than if it wasnt blanked/clamped off, so the FPR is definatley not up to the task.

The FPR i'm getting is made for turbo engines, alot of guys with jap cars use them.
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Selling 1985 GTV6.

Ecu and injectors, lightened.....plays music.
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Re: Inlet Manifold Design

Post by MR2 Zig »

With your bigger injectors and fuel return line blocked and still not enough fuel, your pump may be the holdup. Check the fuel lines under the car (if not done already) for kinks. Check your fuel strainer (in tank) too (I'm thinking of different places that there might be blockage of fuel flow).

Do the big hp turbo guys use bigger fuel lines than stock? I am asking this as it relates to flow.
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GarthW
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Re: Inlet Manifold Design

Post by GarthW »

Hey Zig, yeah i'm pretty sure they would use larger hoses for better flow.
But with the sort of power i'll have, i ended up getting 8mm ends on pump the same as standard.


Will end up running a braided line from pump to the engine to make it nice and safe.


Could just imagine with the larger pump having a fuel hose fail.. :roll:
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Ecu and injectors, lightened.....plays music.
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Re: Inlet Manifold Design

Post by MR2 Zig »

That kind of failure could make for a bad country song..."cry me a river(of gas)" :D

I just wasn't sure about how much hose size changed with horsepower level, or if it changed at all.
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Re: Inlet Manifold Design

Post by Duk »

Obviously not attached to an Alfa engine, but I decided to build (tho yet to test) a prototype reverse collector style plenum chamber manifold for my turbo charged and supercharged Toyota MR2.
I didn't take a photo of the inside once I welded on the bell mouths, but you get the picture.
1 and 4 are paired together and separated by the internal devider from 2 and 3. This decision was made after watching Mats manifold simulation and seeing the robbing of air from adjacent runners. 1 and 4 (or 2 and 3) can rob from each other, but because there is the longest possible even spacing between their respective induction strokes, it should (hopefully) have minimal effect.
The idea behind this design is that there should be very little favoritism for any of the runners as each runner is in essentially the the exact same orientation to the plenum entry as the others:
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slyalfa
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Re: Inlet Manifold Design

Post by slyalfa »

hmm kinda looks like a quad 4
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2.3L 160bhp


but the later one was 190bhp

and the intake changed into this

Image



BTW the bosh pump should be good for around 400bhp so it is ether going or you have a plunged filter. or the sock in the tank needs to be cleaned. Or bad power to the pump. As a rule they are very good pumps that last a long time. I know the guys that run big power like to get them. Some times running 2 in series. for power in the 1000bhp range. The so called race pumps seem to fail a lot. take a ton of power and heat the gas.
Variable voltage feeding the pumps seems to be taking off. Run the pumps only as fast as you need. Extending the pump life and reducing heat and power draw.
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Re: Inlet Manifold Design

Post by mjr »

im not trying to rain on parades here, and maybe i risk getting shot down, but this quest to redesign the intake is totally pointless on the 75 and 12v IMO, and not necessary with the Hp figures were talking about.

if Autodelta, and gregs super charging for instance could run between 230-250 hp with the standard plenum design, just lightly ported out (in group A case), with larger diameter throttle body and afm, why try to re invent the wheel!!?? you spend all that time and energy ditching the factory plenum and runners, only to be losing a shed load of power in the poor factory inlet ports and valve pockets on the 12v anyway. it's tosh. Ive seen 2.5's and 3.0 alike nicely tuned on standard runners and plenum, all be it opened up a little and the factory castings cleaned up.
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Re: Inlet Manifold Design

Post by Duk »

mjr wrote:im not trying to rain on parades here, and maybe i risk getting shot down, but this quest to redesign the intake is totally pointless on the 75 and 12v IMO, and not necessary with the Hp figures were talking about.

if Autodelta, and gregs super charging for instance could run between 230-250 hp with the standard plenum design, just lightly ported out (in group A case), with larger diameter throttle body and afm, why try to re invent the wheel!!?? you spend all that time and energy ditching the factory plenum and runners, only to be losing a shed load of power in the poor factory inlet ports and valve pockets on the 12v anyway. it's tosh. Ive seen 2.5's and 3.0 alike nicely tuned on standard runners and plenum, all be it opened up a little and the factory castings cleaned up.
The thing is, just quoting X-hp doesn't tell much of the story.
I'm after the broadest possible (NA) torque curve that I can achieve. And that can be achieved with longer runners. Dual resonance characteristics of keeping the 2 plenum chambers separated at lower engine speeds and then joined at higher speeds should help this too.
But yes, the standard ports have an awful finish.
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Re: Inlet Manifold Design

Post by mjr »

but the factory runner and plenum will already be designed for the broadest torque across the whole rev range, with power in mind. manufacturers spend a lot of effort to get the runners optimal length to make the engine most driveable. Both the 3.0 and 2.5 have very good torque low down for the runer length. I really dont see that you will improve things by altering the runner length. Surely you will be compromising power higher up in the rev range to gain a little more torque, unless you go for smaller twin plenums and a valve? personally I agre on that front, I would have two smaller plenums, like the alfa 6 if your lengthening and opening runners, otherwise you may run into standing wave issues using a larger single plenum. You need to keep the plenum as compact as possible with longer, larger runners. This is why Alfa will have gone with one small plenum for the length of the runner. For the effort involved, I don't think you are going to see very noticeable improvement in the 12v, unless you are sorting the entire intake and exhaust geometry out too. It would be interesting to have all the measurements and flow figures for the current geometry, and put them through simulation software.
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Re: Inlet Manifold Design

Post by Duk »

"1 experiment is worth 1000 expert opinions."
Best way to learn is to do :D .
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Re: Inlet Manifold Design

Post by Mats »

Duk wrote:"1 experiment is worth 1000 expert opinions."
Best way to learn is to do :D .
I could not agree less. If you're talking real experts and not internet experts.
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-Scuderia Rosso- Now burned to the ground...
-onemanracing.com-
-Strandberg.photography-

GTV 2000 -77 - Died in the fire.
155 V6 Sport -96 - Sold!
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