200whp with stock N/A rotating assy?

[e21jps]

Hey John. nice to see some updates here.. i keep forgetting to come and check out the progress,

I can definately backup your findings with bigger valves and totally agree that just banging in os valves does absolutely nothing or even hurts flow unless the rest of the port and seat area is reworked to suit

I have tested my bare itbs with trumpet and it flows 265cfm which is WAY above the potential of any m20 head so i think what your seeing wen the flows start coming back together at higher lift is the port itself backing up like they do after they hit that turbulent point. At which time what ever intake will have a lesser affect.

interesting to note that after you did fit the larger valves then fitted my itbs with no other changes to the port the mid range flow actually increased a little!! It would be nice to see the comparison on a graph.

After your strategic porting then even with the intake on flow still smashes all the rest at all lift's and you have a nice fast port... thats what works best ;D
(i have tested "Fully ported" heads that look very pretty but actually flow sweet FA more than a std port!)

[digger]

(i have tested "Fully ported" heads that look very pretty but actually flow sweet FA more than a std port!)

or even worse than that, the one MM sold me flowed upto 5% less than stock but they claimed a 12% increase. To be fair there was one lift point where it matched their claim....

[guibo09]

or even worse than that, the one MM sold me flowed upto 5% less than stock but they claimed a 12% increase. To be fair there was one lift point where it matched their claim....

I have no real data or experience with porting, but what MM does with all those little steps and notches just does not sit well with me and looks plain wrong.

When I build my stroker, I will keep the original design philosophy as much as possible. One important part of that will be keeping the original piston top design which I'm sure is very well optimized for a proper quench and flame front propagation in a 2 valve.

[ForcedFirebird]

Hey John. nice to see some updates here.. i keep forgetting to come and check out the progress,

I can definately backup your findings with bigger valves and totally agree that just banging in os valves does absolutely nothing or even hurts flow unless the rest of the port and seat area is reworked to suit

I have tested my bare itbs with trumpet and it flows 265cfm which is WAY above the potential of any m20 head so i think what your seeing wen the flows start coming back together at higher lift is the port itself backing up like they do after they hit that turbulent point. At which time what ever intake will have a lesser affect.

interesting to note that after you did fit the larger valves then fitted my itbs with no other changes to the port the mid range flow actually increased a little!! It would be nice to see the comparison on a graph.

After your strategic porting then even with the intake on flow still smashes all the rest at all lift's and you have a nice fast port... thats what works best ;D
(i have tested "Fully ported" heads that look very pretty but actually flow sweet FA more than a std port!)

Yeah, theoretical flow according to dynomation using rough math to convert from 1.5" Hg to CFM, a 40mm TB should flow over 200. And yes, you are absolutely correct. The most flow with the smallest CSA possible keeps the velocity up and makes for a good head. People tend to look at peak and high lift numbers (on head flow as well as dyno plots) and often miss the "area under the curve". This is why i like to include AVG flow numbers across the lift points.

On a side note, the Extrudabody throttles were quite out of balance. Your throttles share a shaft which should make them easier to balance since it's really three pairs where the EB kits are 6 individual throttle shafts with adjustments in between. After using a balancing, the EB kits became much easier to tune, and sound much better. Curious to see how well the RHD ITB's are in tune with each other.

If things keep going thew way they are, seems like we will be working together often. Would be great to have a hub on this side of the pond for support/sales, as well as the development of Motronic tuning for those that are looking for a plug and play setup.

[e21jps]

Yes looking forward to it too i can see we will have plenty stuff to work together on, especially the ecu development i get asked about that almost every day. We are still working on ideas for air boxes and i think i have a bit of a clever idea for a simple cost effective solution but even then getting the best out of a conversion will still require a few tweaks to the tune.

My other customer complained a bit about the balance on his Eb ones too but im sure it is possible.

edit: mine are usually very close because all the shafts and parts are quite accurately cnc cut but sometimes you still might see maybe the tiniest difference across one body if you have an accurate enough sycronometer. Between each body is easy because you just turn the little grub screw

[guibo09]

Can you share more details about your air box idea?

I think you would have a huge winner on your hands if you offer an ITB + airbox + tune in a complete package.

[ForcedFirebird]

Yes looking forward to it too i can see we will have plenty stuff to work together on, especially the ecu development i get asked about that almost every day. We are still working on ideas for air boxes and i think i have a bit of a clever idea for a simple cost effective solution but even then getting the best out of a conversion will still require a few tweaks to the tune.

My other customer complained a bit about the balance on his Eb ones too but im sure it is possible.

edit: mine are usually very close because all the shafts and parts are quite accurately cnc cut but sometimes you still might see maybe the tiniest difference across one body if you have an accurate enough sycronometer. Between each body is easy because you just turn the little grub screw

Yes, I believe the RHD will be closer in balance.

I have tested small differences in diameter before, and it's negligible. In fact many cases (885 head being one of them), a port match can actually hurt the flow pending design of the head and manifold used.

Can you share more details about your air box idea?

I think you would have a huge winner on your hands if you offer an ITB + airbox + tune in a complete package.

While yes, this would be great, keep in mind the added cost.

[e21jps]

Can you share more details about your air box idea?

I think you would have a huge winner on your hands if you offer an ITB + airbox + tune in a complete package.

The cost has been the biggest obsticle so far but i have come up with what i hope is a cunning way to fit and seal an air box backing plate half way up the existing trumpets while still supporting it directly off the itbs so we are not relying on the little clamps. Then we can just make a simple fiberglass and/or carbom fiber plenum to clip onto it etc.

[guibo09]

The cost has been the biggest obsticle so far but i have come up with what i hope is a cunning way to fit and seal an air box backing plate half way up the existing trumpets while still supporting it directly off the itbs so we are not relying on the little clamps. Then we can just make a simple fiberglass and/or carbom fiber plenum to clip onto it etc.

Curious to see what you come up with. After mental brainstorming, the best I came up with is sandwiching a back plate between the trumpet collars and the throttles using some gaskets (or o-rings).

[ForcedFirebird]

The biggest problem is going to be what Digger ran into with booster clearance. Really, the trumpets should have one throttle diameter clearance in all directions, and as they are now, they lay right on top of the booster.

[digger]

I have no real data or experience with porting, but what MM does with all those little steps and notches just does not sit well with me and looks plain wrong.

When I build my stroker, I will keep the original design philosophy as much as possible. One important part of that will be keeping the original piston top design which I'm sure is very well optimized for a proper quench and flame front propagation in a 2 valve.

I don’t agree a lot with what they do and the proof is that their engines don’t really seem to perform any better than ones done the traditional way at least that was my experience and the consensus I found through others with different engines from them. Don’t get me wrong some of their parts are great and they have been doing things for along time so have a wealth of information and experience and are good to deal with.

The biggest problem is going to be what Digger ran into with booster clearance. Really, the trumpets should have one throttle diameter clearance in all directions, and as they are now, they lay right on top of the booster.

The biggest problem was both the hood and booster. If you shorten the runners the hood clearance improves but the booster clearance doesn’t drastically change unless you make it drastically shorter which might be too short for best engine performance on most builds.

Ultimately its difficult retain the really long full length runners and sufficient clearance around the entry pf bellmouths without some sort of curved trumpet arrangement especially for runner 1 and 6.

[bradnic]

The biggest problem was both the hood and booster. If you shorten the runners the hood clearance improves but the booster clearance doesn’t drastically change unless you make it drastically shorter which might be too short for best engine performance on most builds.

Ultimately its difficult retain the really long full length runners and sufficient clearance around the entry pf bellmouths without some sort of curved trumpet arrangement especially for runner 1 and 6.

Any chance of replicating the H27SP setup? Seems to have long runners, booster clearance and a compact design, curved as you suggest.

[digger]

Something like that could work but never looked at the details myself about clearing the RHD linkage, fuel rail and injector harness etc. Not a huge fan of plenum entry direction being opposite to the runner entry direction but this might not be an issue.

[ForcedFirebird]

This. Thing. Sounds. Amazing.

Went with dual 2" exhaust, x pipe ~34" from collectors, twin 12" resonators.

10am appointment at dyno.

This one is staying Alpha-N Motronic 1.3.

[ForcedFirebird]

Cam is broken in. Needs another oil change before dyno, but here is a free rev just for giggles.

https://www.youtube.com/watch?v=MlqHLCldWdk