Richard,
I was hoping this wasn't going to turn into an "Intake Manifold Design" thread, however here is a bit of info for those that have an interest in this subject.
Firstly, i can not accept credit for the fabrication of the Intake manifold. It was designed and fabricated by a good friends of mine Jim, he fabricates most types of Int/Exh manifolds from his company MENTAL PERFORMANCE FABRICATIONS located in Sydney Australia. Jim is also responsible for fabricating my Exh manifold too and as you can see in the video it copes well in extream conditions.
I take full credit for the programming of the ECU as this is what i do. As can be seen in the pics, the new Intake has over double the runner lenght of the standard Cosworth item. Not only does this increase air speed it also has the added benefit of having a larger volume within the runner. What must be remembered is air DOES have mass and trying to fill the Cyl as much as possible in the small time frame the Intake valve(s) are open is one of the many keys to making gains in Hp/Torq.
Having dynoed 100's of cars over the years i have learnt plenty from OTHER peoples mistakes. Over the years i have made up my own simple theory. If you make a mod to the engine and it make more power, then you have simply filled the Cyl's better. I am of course refering this to mechanical changes let alone programming changes (A/F mix, Ign advance etc)
What also MUST be remembered is that a Dyno SHEET only shows FULL THROTTLE gains as most dyno runs are at 100% Throttle openings.
Now to the manifold. Note; the following is at 100% throttle. A back to back test (SAME boost, fuel, dyno etc) shows that below 3700rpm there was NO gain in power nor torque. I put this simply down to the fact that below this rpm there is adequate time to fill the Cyl's, infact i am certain there is reversion below this rpm. Reversion is when the Cyl's completely filled and the piston is still on its up stroke with the Int valve still open. This only occures at low rpm as at high rpm the air mass cannot keep up with the piston speed and therefore not fill the Cyl's completly and this is one of the reasons to why the torque drops of in the higher rpm range.
Above 3700 rpm there were excellent gains in both Hp and Torq. Even at 7000rpm there was still a 10 Hp gain (Flywheel) indicating that the longer runners did not "Nose over" as we thought might have happened.
Now regarding small throttle openings. This is what the dyno sheet cannot show you. There was a MASSIVE difference in throttle responce during transition throttle and small throttle openings. Again i will come back to my simple theory, if the engine make more Hp/Torq you are better filling the Cyl's. As an example, if we are at 10% throttle, you are in fact "Throttling" the engine so therefor your not completly filling the Cyl's.
What is happening with the new Intake manifold is that with the same throttle openings there is better Cyl filling due to the longer runners therefor more Hp/torq generated at the same throttle % compared to the standard manifold and thus giving a much sharper throttle respone.
This was also proven whilst retuning the engine with the new intake manifold while the load/rpm points were held static for optimum MBT tuning.
Also this is backed up in an unusual manner by the factory idle control solenoid. As you can see in the pics, the solenoid is attached to the throttle body and was not affected in any way by the install of the new intake manifold. The solenoids "settings" were NOT touched in the ecu software.
What we found after fitting the manifold was, the Idle contol solenoid struggled to maintain a steady idle. It would idle between 1200-1300 rpm. Obviously the new intake manifold had made the solenoid MUCH more sensitive to the air it would bypass. The cure was to fit a 4mm "restrictor" within the solenoid and the throttle body and this gave us the stable idle (880rpm) we had prior to the new intake manifold being fitted.
In my opinion the gained rpm over the original 880rpm setting comes from the gained responce of the engine to any form air flow to the manifold. The other noted aspect was the engine is also alot more difficult to "stall" due to the lack of throttle while engagining the clutch while taking off. The IDLE ign timing/fuel delivery setting were not changed in any way nor was the throttle body "butterfly" position and there were NO manifold leaks to say that this was the reason for the gained rpm at idle.
I also want to make it clear i am in no way trying to "send work" Jims way. I spoke to Jim prior to this post asking if he was interested in having a contact number or email address posted and his reply was "I'm booked out for the next 6 Months".
I am passing on this info as per Richards request and i originaly sent the "sight galss" video to Richard as i knew it would have been of interest to him, i did not have any other intention other than that. The pics Richard has posted were sent to him at his request. I do understand that there are guys out there interested and this is why i asked Richard to post the pics so you guys can have a better understanding of what you were looking at in the video.
I hope this thread was of some assistance to those interested cos it took me bloody ages to type out
ops:
Jake