Hi,

I have modified my second upper intake v6 manifold

There are the pictures :

(Thanks Patrick for the picture resizing advice)
















I hope to get better upper rpm and get extra some hp

I have made some other mod and maintenance like exhaust manifold porting, removing cat, sport round muffler and stainless Steel full custom exhaust. Accel Ignition coil performance, performance SPARk câble, ngk new iridium SPARk plug, kn air filter and others oil and gas kn filter, no egr.m, New oil castrol titanium 5w30 with a9 motoreco vl oil additive, All sensors are New, New clutch and oil pan, Idecarbonized the engine with liqui moly intake 5111 and then with a tunap 133 intake bottle.. .

I let you know when I Will install This intake but at the same time I Will change the injectors

[This message has been edited by zobari (edited 03-02-2019).]

For sure it will make a difference.

With a stock 2.8 (except for ported exhaust manifolds), I have observed an absolute pressure of 85 kPa in the plenum at WOT.

Therefore, I take the hypothesis that there is a 15 kPa pressure drop across the throttle body and neck.

Hence, I would suppose that if you succeed in maintaining atmospheric pressure in the plenum at WOT, you could increase top-end torque by 18%.

Ok thanks for your response and that's very interesting. For me.

I Will proceed to the installation This month with the 6 accel 15 lb injectors replacement.

I Will maybe get my 88 gt dynoed next month after the modification.

quote Originally posted by zobari: There are the pictures...

I'm amazed that individuals who are wizards in the shop often have no clue how to properly resize and post images.

I felt this custom intake was rather special... so here's Zobari's images re-posted so that we can all see them.

[EDIT] Zobari has now copied and pasted the six images I re-sized into his opening post (which is what I was hoping he'd do), so I've deleted them from here.)

[This message has been edited by Patrick (edited 03-02-2019).]

Will the non aerodynamic square hurt air flow, thoughts? Or will it allow more air to be in the manifold for the motor to take in?

Will the top clear the deck lid?

quote Originally posted by Spadesluck: Will the non aerodynamic square hurt air flow, thoughts? Or will it allow more air to be in the manifold for the motor to take in?

The concept of a large plenum full of relatively "still air", ready for consumption by each cylinder, is a common concept...

See Ferrari:


Honda:


Previous incarnation of La Fiera's car (which produced good power):


Toyota went against the grain here. I haven't seen other cars like it!

[This message has been edited by pmbrunelle (edited 03-02-2019).]

I have take the wcf intake manifold as example with my custom touch for the back side and also for the upper side.

I have paied 180 dollar for the weld working.

I think that the wcf intake is too expensive.

I Will clean and repaint it in red as oem color

[This message has been edited by zobari (edited 03-02-2019).]

I was going to compliment your welding skills, but I see you hired a welder.

Like mentioned above, the purpose of an intake plenum is to be an air reservoir for the cylinders. The stock plenum has very little volume, so there isn't much air for the cylinders to draw from. The larger volume will allow each cylinder to take in more air during the intake stroke. And that will improve torque.

yes exactly the first restriction is the neck and then the volume is very thin and insufficient for a v6 engine i think

The trueleo intake will be maybe a bit better in performance but it's very expensive.

That's my last mod on my 2.8 v6 engine

[This message has been edited by zobari (edited 03-02-2019).]

quote Originally posted by tshark: Will the top clear the deck lid?

I have measured with a 8cm bottle height and I can close the deck lid.
I have demanded to the welder 6 cm for the height on the top.
1,5cm for the bottom.

[This message has been edited by zobari (edited 03-03-2019).]

IIRC - I believe it was the PGP V6 intakes that widened the neck and added more dept (and volume) to the plenum and got 20 more hp.

After 11 months

[This message has been edited by zobari (edited 12-09-2019).]

Heh heh... that looks massive! I'm quite surprised that the decklid is still able to close.

So, how's it run? Notice a difference?

Hi,

I can close the deck lid without any problem.

I just start and let running the engine and let warmed the engine in closed loop for 20 minutes in idle.
I Will test the modification This week or next week when the weather Will be better.

I have changed the 6 injectors wiith new accel 15 lb performance disc style and New fuel pressure regulator at the same time.

The Last mod is changing the y pipe by a less restrictive y pipe from fiero store that I've buy.

[This message has been edited by zobari (edited 12-09-2019).]

Can't wait to hear about your test drive . Seems like you got a great deal on the welding. So you did the cuts on the intake and also the new pieces yourself? How did you do that and was it difficult?

Hi,

I have hired a welder (tig aluminium weld)

I have drawed lines where exactly he must cut and I told what I want like measure and shape...

Pay attention for the pcv vaccum hose under the neck you must weld it 2cm to the left (to the trhottle body) because the fuel rail is just under I have rewelded this area..

Before weld working :




Here I have told him to rework also the upper neck :



The vacuum hose for the brake booster line is different between 1988 and 86-87 the hole is bigger for the 88 and I must cut my old 1988 intake and weld this piece of alu on this moded 86 upper intake manifold.

Next week I Will test and let you know.

Next Last mod, remove air filter box restriction and I Will change the y pipe with a performance part and after these Last mod I stop the mods on my engine.

[This message has been edited by zobari (edited 12-11-2019).]

With a 3.4, the middle intake is a big restriction. I used a ported F-body 2.8 intake for my application. The gains start at exactly 4500 rpm where my much older 3.4 dynos would peak.

[This message has been edited by lou_dias (edited 12-11-2019).]

Nice work but there is more that has to be done if you want max gain..
Ive done maybe a hundred of flow measurement on this intake system. The flow limitation is in the shape of the middle intake manifold. The air path has to be redirected.

Thanks for the information.

I hope to get some torque and hp in low and middle rpm a bit better breathe et hp rpm to 5500rpm if possible, a > 5500-6000rpm intake doesn't interest me that's too high for our old engine i think.
I wil work on the air filter box restriction and i let you know next week with a test drive

[This message has been edited by zobari (edited 12-12-2019).]

Why not mod the intake like the PPG cars? That’s what I’m doing as well as Lou’s mod on the middle intake.

[This message has been edited by jjd2296 (edited 12-13-2019).]

quote Originally posted by zobari: I have hired a welder (tig aluminium weld) I have drawed lines where exactly he must cut and I told what I want like measure and shape...

Wait, you just gave him the stock manifold with some lines drawn on it and he did the cut-outs on the manifold, cut out all the pieces needed to make the box, etc., and then welded everything and he did all of that for only 180 euros??? Man you got an incredible deal!!

quote Originally posted by Notorio: Wait, you just gave him the stock manifold with some lines drawn on it and he did the cut-outs on the manifold, cut out all the pieces needed to make the box, etc., and then welded everything and he did all of that for only 180 euros??? Man you got an incredible deal!!

Yes exactly.
And it's a good welder and the price is low.

[This message has been edited by zobari (edited 12-15-2019).]

Hello,

I've drove the car Today around 30km.

The car runs good.

The low rpm is better (because I've change the injectors maybe)
I've push the engine at 5500rpm for my test and the engine takes easily the rpm I feel a better torque and gain some hp the car is faster than before.

Next Last mod is change the y pipe by a New y pipe performance and put new synchromesh transmission oil.

[This message has been edited by zobari (edited 12-18-2019).]

Very cool mod! Would love to see a dyno run if you ever get a chance.

Dyno is a bit expensive 200euro I don't think pass a dyno run with my fiero.

I can drive at low rpm now, before the mod and changing the 6 inejctors and fuel pressure regulator the car vibrate a bit and no power under 2,5k after 2 gear now is far better and no vibration.

The car push hard at 5500 rpm I didn't tested after 5500rpm but maybe I Will test at 6000 rpm to see if the car keep the horsepower or not at 6000k but I Will test it after changing the y pipe and I come back to you.

[This message has been edited by zobari (edited 12-18-2019).]

I have modified my y pipe and remove restrictions (too much metal inside and the result that is decreased by 30% the volume before the downpipe).

with this upper intake and new y pipe, i can rev up to 6000 rpm without loss in performance.
The engine breath et keep power in higher rpm better.

But before 3000 rpm not much difference than before.

Ok that's not a corvette of course but a bit power and better rpm extension is good for me with this 2.8, i'm satisfied with these mods.

If you want see the final result in the engine bay :

video modded intake and ypipe fiero engine bay

[This message has been edited by zobari (edited 06-10-2020).]

Very well done!!

Very nice job... but get some shielding or exhaust wrap on that Y-pipe before you cook your ignition coil and ICM !

Hi Patrick,

Yes I have Aluminium sheet that I will cut and in order to protect the ignition coil and distributor.
I will make my own sheet shield this week.

I have seen it one year ago but thank you for your advice.

That reminds me of Igor in Young Frankenstein - "What hump?"

Would be interested to hear if there are any power gains.

Here is a video with engine sound and I've installed an ezlip pro for the front bumper :

Video fiero with engine sound

[This message has been edited by zobari (edited 07-11-2020).]