Turbo Bridgeport discussion
10-22-2016, 04:57 AM
#1
Turbo Bridgeport discussion
Been trying to work out why my Turbo Renesis Bridgeport is so ineffective ........yet we see such huge gains on PP engines .
My theory :
On the Renesis the only VE gain that can be had seems to be in replacing the carried over exhaust gases with intake air . Looking at the chamber at that point in it's cycle, it looks like somewhere around 5% of the total swept area . So a maximum gain of that magnitude is possible. Looking at my results so far , i may be getting close to these gains , but nowhere near what a PP engine achieves.
So I started to think about why such big gains are possible on PP engines .
I haven't seen any discussion on this so I don't know what explanations have come forward from the 7 guys.
The Peripheral port stays open way longer than the renesis side port and therefore allows much more air to flow through it ...it keeps flowing after the chamber has compressed the exhaust gas .
I'm actually thinking the gains are being made ..............outside of the engine . What if the intake air goes straight through the engine and into the exhaust . The fuel then ignites creating combustion just before the turbo . This creates more heat and pressure outside of the engine ..similar to antilag!Result is turbo is spooled up in part by this .... meaning the engine doesn't have to do it . Result = more power .
Just a theory ... anyone else got any ideas on this ?
Cough ...Teamrx8 ?
My theory :
On the Renesis the only VE gain that can be had seems to be in replacing the carried over exhaust gases with intake air . Looking at the chamber at that point in it's cycle, it looks like somewhere around 5% of the total swept area . So a maximum gain of that magnitude is possible. Looking at my results so far , i may be getting close to these gains , but nowhere near what a PP engine achieves.
So I started to think about why such big gains are possible on PP engines .
I haven't seen any discussion on this so I don't know what explanations have come forward from the 7 guys.
The Peripheral port stays open way longer than the renesis side port and therefore allows much more air to flow through it ...it keeps flowing after the chamber has compressed the exhaust gas .
I'm actually thinking the gains are being made ..............outside of the engine . What if the intake air goes straight through the engine and into the exhaust . The fuel then ignites creating combustion just before the turbo . This creates more heat and pressure outside of the engine ..similar to antilag!Result is turbo is spooled up in part by this .... meaning the engine doesn't have to do it . Result = more power .
Just a theory ... anyone else got any ideas on this ?
Cough ...Teamrx8 ?
10-22-2016, 09:48 AM
#3
Brettus,
I think my bridge is coming out around the first of the year. After 80k miles, it's time for something new. If I can work out a couple bugs in the tune this weekend, I'll dyno it next weekend at a local event.
Side exhaust allows for zero overlap, and lower emissions from the factory setup. Not great for power gains or engine longevity (in it's renesis form).
I think my bridge is coming out around the first of the year. After 80k miles, it's time for something new. If I can work out a couple bugs in the tune this weekend, I'll dyno it next weekend at a local event.
Side exhaust allows for zero overlap, and lower emissions from the factory setup. Not great for power gains or engine longevity (in it's renesis form).
10-22-2016, 12:52 PM
#4
I think a lot of things are going on. PP intakes tend to allow better charge homogenization and the A/F mixture will be more uniform. There seems to be a big difference in injector sizes and balancing Pri and Sec airflow and fuel addition...if you get it wrong there seems to be power left on the table. The shape of the combustion chamber makes this a lot more critical than in piston engines. Looking at the gains in piston engine combustion chamber shape and charge stratification made in Mazdas SkyActive engines that allows more power with less fuel.
I still think that the major issue with the Renesis is Exhaust side flow......and Heat retention
I still think that the major issue with the Renesis is Exhaust side flow......and Heat retention
10-22-2016, 03:05 PM
#5
I think a lot of things are going on. PP intakes tend to allow better charge homogenization and the A/F mixture will be more uniform. There seems to be a big difference in injector sizes and balancing Pri and Sec airflow and fuel addition...if you get it wrong there seems to be power left on the table. The shape of the combustion chamber makes this a lot more critical than in piston engines. Looking at the gains in piston engine combustion chamber shape and charge stratification made in Mazdas SkyActive engines that allows more power with less fuel.
I still think that the major issue with the Renesis is Exhaust side flow......and Heat retention
I still think that the major issue with the Renesis is Exhaust side flow......and Heat retention
My Renesis doesn't do this even though the exhaust size isn't really a restriction at that point .
If you saw my initial Renesis BP results at 10 psi ...It was actually looking quite promising as the engine was flowing way more air than a normal engine would at 10psi . If my theory were correct my engine should have made more power at 10psi than it did before the BP . It didn't .............. BUT , with my manifold design , all of the extra flow would be flowing straight through the wastegate . There is no opportunity for it to have the effect I suggested above .
So , this actually adds weight to above theory.
Last edited by Brettus; 10-22-2016 at 03:10 PM.
10-27-2016, 08:34 AM
#8
Release the twins.
