Discussion
When i upgraded the 400 engine to a 500 engine i reused the 400 air flow meter and plenum. Is there any difference between the 400 and 500 for these items? Think i read that the plenum may be larger?
I also have a MA mapped Tornado chip in the ECU, would this need remapping with a bored out plenum (71mm) or just the throttle pot adjusted accordingly?
Thanks, Jon.
I also have a MA mapped Tornado chip in the ECU, would this need remapping with a bored out plenum (71mm) or just the throttle pot adjusted accordingly?
Thanks, Jon.
I believe the 3.9/4.2 plenum was used on the 400 as per the 500's, so I do not think there is any difference at all.
If you tak th eplenum out to 72mm it will need re-mapping as you will be increasing the available air by approx 25% for any given opening above the current level, and the fueling will need to correspond accordingly.
It isn't a plug and play upgrade.
If you tak th eplenum out to 72mm it will need re-mapping as you will be increasing the available air by approx 25% for any given opening above the current level, and the fueling will need to correspond accordingly.
It isn't a plug and play upgrade.
Thanks Johno. Thought that may be the case. Although i also thought that the throttle pot only indicated throttle intention and the larger air throughput in the big plenum would be measured by the AFM and fueling changed accordingly. So the throttle pot does more than i think.
Cheers, Jon.
Cheers, Jon.
The throttle pot only tells the ECU the butterfly position, nothing else.
The AFM meaures the the amount of air flow to the engine and the temp of that air.
The Lucas ECU is set up on the basis of the throttle allowing a given amount fo air into the system, and then there will be corrections made via lambda rsponse, coolant temp, air temp etc . . But the system assumes the amount the engine is getting is based on the original throttle size. By chnaging the throttle size you are ncreasing the available air to the engine by 25% approx.
The AFM will assume the engine is under greater load as there will be more air flow, however, the TPS will be telling it the throttle isn't open enough for that amount of air (load) and the ECU will interpolate between the readings and decide which it thinks is right.
Whatever it ends up deciding, it won't be the right decision as the equation has been changed by the butterfly size, and a re-map is required to make sure the fueling responds to the newly avialable air, and the ECU is aware of the increased air flow etc . .
There are others on here who will be able to articulate this better than I though
The AFM meaures the the amount of air flow to the engine and the temp of that air.
The Lucas ECU is set up on the basis of the throttle allowing a given amount fo air into the system, and then there will be corrections made via lambda rsponse, coolant temp, air temp etc . . But the system assumes the amount the engine is getting is based on the original throttle size. By chnaging the throttle size you are ncreasing the available air to the engine by 25% approx.
The AFM will assume the engine is under greater load as there will be more air flow, however, the TPS will be telling it the throttle isn't open enough for that amount of air (load) and the ECU will interpolate between the readings and decide which it thinks is right.
Whatever it ends up deciding, it won't be the right decision as the equation has been changed by the butterfly size, and a re-map is required to make sure the fueling responds to the newly avialable air, and the ECU is aware of the increased air flow etc . .
There are others on here who will be able to articulate this better than I though
clive f said:
I`ve been running a 72mm plenum for 2 yrs with no problems on the lucas, as many other people have, just needs the fuel pressure tweaking up a tad.
The 500 engine i have has V8D stage 3 heads, ACT 45mm ported inlet manifold and trumpets, Stealth cam and now an ACT smooth bore induction kit. The next stage for the engine seems to be the plenum and AFM constrictions. YES I KNOW the best route would be aftermarket ECU and ditch the AFM, but it's a bit out of my comfort zone and wallet at moment. My engine has been setup by Mark Adams with his Tornado chip and the result is very smooth. Further mods would only require a couple of hours of his time and rolling road so this is not the end of the world.My thoughts are to change the following:
Plenum 72mm
Bored out or larger AFM
Magna parva plenum spacer
Precats out
Offords treatment to exhaust.
The engine puts out 290bhp and 320ftlb (at fly measured by "Austec" and "Perfect Touch" rolling roads) but with higher mid range bhp than i have seen from other dyno printouts from similar powered engines posted on PH. Think the Stealth cam is more mid range than all out peak top end power. Just after eeeking out another 15-20bhp
Who is doing bored out AFM's or would a jag unit be better? Anyone got contact details for Mark Adams?
jon.
Chimjunkie said:
clive f said:
I`ve been running a 72mm plenum for 2 yrs with no problems on the lucas, as many other people have, just needs the fuel pressure tweaking up a tad.
The 500 engine i have has V8D stage 3 heads, ACT 45mm ported inlet manifold and trumpets, Stealth cam and now an ACT smooth bore induction kit. The next stage for the engine seems to be the plenum and AFM constrictions. YES I KNOW the best route would be aftermarket ECU and ditch the AFM, but it's a bit out of my comfort zone and wallet at moment. My engine has been setup by Mark Adams with his Tornado chip and the result is very smooth. Further mods would only require a couple of hours of his time and rolling road so this is not the end of the world.My thoughts are to change the following:
Plenum 72mm
Bored out or larger AFM
Magna parva plenum spacer
Precats out
Offords treatment to exhaust.
The engine puts out 290bhp and 320ftlb (at fly measured by "Austec" and "Perfect Touch" rolling roads) but with higher mid range bhp than i have seen from other dyno printouts from similar powered engines posted on PH. Think the Stealth cam is more mid range than all out peak top end power. Just after eeeking out another 15-20bhp
Who is doing bored out AFM's or would a jag unit be better? Anyone got contact details for Mark Adams?
jon.
Chimjunkie said:
Thanks for the info Meatball. If you remember where then please let me know. Mark from Blitzracing has just put an interesting post up on the electronics of the afm. Got me thinking about whether the afm could be bored out and recalibrated rather than remapping the ecu...
Thats all the guy i brought mine from did..he used the existing lucas electrickery stuff and stuck it in a alloy tube (im sure its more complicated than that 
)I`ll PM hes number to you tonight.Gassing Station | Chimaera | Top of Page | What's New | My Stuff