roller lifters with 2.8

[Superdave]

damn that thing sounds good!

[1988GTU]

I liked that vid and the Roadsport B/C start 2 vid.

[3400-95-Modified]

Not only did that raise your torque just a bit but also I think moved it to a more usable area for you... Your looking at peak torque close to 4800 rpm... rather than 3800 like before. I would also try to investigate and see what is happening right when you get that dip on the graph... A dip like that in both the torque and HP means you dropped something... Spark changed or fuel dropped off or went to rich right then.. Something isn't right.

[Purple pit]

Can you get something like these for your carbs?

http://www.emeraldm3d.com/jenvey-aluminium-air-horns.html

I would say(after rereading the link I posted) that the 40mm(or 60mm) long stack would work best for you. Just click on the left side photo. Thinking that you already have 90mm long stack, just not with the trumpet/horn outside edge.
I would say the shorter stack with the tumpet end will help get you where you want to be. After you fix the problem that was seen in the dyno graph that is.

[veekuusi]

Summary of the 3 different kind of carb/intakes that have been tested in the dyno.
GM 60 degree 2.8 V6 .
All the reading are WHP .

3 bbl PMO carb (3 x 50 mm) (with extra long intake runners)
252 hp 7810 rpm
261 Nm (192 lb ft) 5850 rpm

4 bbl Holley (390 cfm db) :
232 hp 7640 rpm
248 Nm (182 lb ft) 5680 rpm

2 X 2 bbl Weber (45 mm) :
238 hp 7740 rpm
260 Nm (191 lb ft) 4790 rpm

Mr 3400-95-Modified has understood it right, there is an issue in the 5000-5500 rpm area.
I am not quite sure what is going on in the engine in that rpm.
The AFR ratio is OK in 3500-8000 rpm.
The lambda reading is 0.88-0.93. That is 12.5-14 AFR.

The full throttle spark advance is 27 degree below 3500 rpm and after then it is 30 degree.

There are pulses in the runners that mix up the flow.
The pulses go "wrong way" , I mean they go "backwater", if you know what I mean.
When they enter the plenum , they interrupt the flow to the runners.
The pulses perhaps disturb the flow worst in the 5000 rpm area.
Who knows?

[Purple pit]

Pressure waves, that site I linked is more or less about that. With the right length of stack you may be able to tune your problem area out or lessen it.

[34blazer]

I suspect it may be the exhaust, maybe the length of primaries or collector length

[Purple pit]

I agree with that and just started thinking the samething. Still think a shorter stack length and more of a horn shape at the end will have a positive effect for this engine.The horn shape aids airflow and the main pressure wave that draws it in.
Trying to think about all the types of waves and how they act/react in the intake track at the sametime makes my head numb. Then there is airflow and how it reacts with the waves at any given time/RPM. Ouch, guess it's not numb.

[veekuusi]

As mr Purple pit said , it might be worth trying different stacks to the carbs.
It may help the issue of power loss in the 5000 rpm range.

But mr 34 blazer suggested that the issue can result from exhaust.
I have been in the dyno nearly 10 times in the resent year and a half.
Every time with the same exhaust .
And this was the first time, engine had power loss in that 5000 rpm range.

It may be possible that this very last intake do not match together with the exhaust.

This is one thread that I found , that deals with the pressure waves:

http://www.yellowbullet.com/forum/showthread.php?t=644746

[Purple pit]

Nice link, some review for me and some new things.
I think you are right on the exhaust and intake not working well together.
Still in the back of my mind there is something that bugs me. It is the effect of weld bleed though into the runners on the intake. Is it helping to mix the air/fuel or making trouble? What are they doing to the pressure waves? They have to be killing some velocity, even if it is a small amount.
Do you have any photos of the inside of the runners on your intake?

[Purple pit]

Way off topic, but I just want to know:
Are there rules that ban body braces in your race class? Out of all the videos and photos of your car and others that you have posted I've never seen a strut/shock tower bar(or anything else other than a roll cage). That car is a unibody right?

[veekuusi]

Way off topic, but I just want to know:
Are there rules that ban body braces in your race class? Out of all the videos and photos of your car and others that you have posted I've never seen a strut/shock tower bar(or anything else other than a roll cage). That car is a unibody right?

Ford Capri is a unibody allright.
There are no rules that ban body braces, as far as I understand the question right.
The body inside can hold allmost everything, roll cage off course by the book .
Outside the car (surface) , the body is very controlled, cars must look like allmost as they came from the factory.

Accurately there is no strut/shock tower bar in my car.
But there is a metal tube, that goes from left fender to the right.

I think it can be seen in many pictures .But here is one more, the tube is painted black.

[Purple pit]

Must have missed that front bar, that works for me. Can you put a bar in the rear mounted to the shock mounts?
Or something like this:

http://www.overkillengineeringmotorsports.com/retrbr.html

How about a sub frame brace(side to side in the front, or front to rear or both)?

From those videos it looked like the rear was rolling side to side a bit more than it should. I have tested my own car with and without a rear bar on the shock mounts. Without the rear(with a front bar)it will lean a bit more, you can see(if you look back in a turn) and feel it. I do have Eibach springs with matching sway bars so that has nothing to do with it. Not really that much of a change with the bars on, but it was a good change. Now for you it may be even better!

[88corsica5spd28]

I've read this entire thread and i registered just to tell you that you have serious skill. That 2.8 sounds vicious at 7000rpm.

Sent from my LG-L38C using Tapatalk 2

[veekuusi]

It is this seasons first race in a week.
7-8 june 2014.
A took a free practice with my car a week ago in a race track, everything seems to be allright.
More power (or specially torque) than ever before, so the ecpectations are high for the results.

I made boxes out of aluminum, so that the carbs do not suck the warm
air out of the engine room.There are holes in the hood, so maybe cooler air now goes to the intake.