Bridgeport RX8
04-07-2010, 07:58 AM
#451
You're still taking a p-port into consideration!
What happens with a Bridgeport? What's the relationship between an increased port volume vs flow with a limited intake flow (low to midrange)? what happens at higher rpms\increased intake flow\velocity?
This is intake wise, then comes the exhaust part which is less experimented on the renesis.
What happens with a Bridgeport? What's the relationship between an increased port volume vs flow with a limited intake flow (low to midrange)? what happens at higher rpms\increased intake flow\velocity?
This is intake wise, then comes the exhaust part which is less experimented on the renesis.
04-07-2010, 09:55 AM
#453
04-07-2010, 06:51 PM
#454
BDC Motorsports
And yes, I can explain it based on BSFC of rotaries vs. piston engines at given AFR. Also based on BMEP difference of all out N/A racing engines
When was the last time you saw a turbocharged piston engine w/ the same size turbos we use to make 500+hp (67mm comps and above in general) using total injector capacities like us? (Say, for example, 4800cc/min for us to barely make 525rwhp)...
B
04-08-2010, 02:19 AM
#457
Tony says, RX8s are GREAT
Are you talking about making a peripheral\side exhaust port hybrid? It may like it may not work 
The problem Ben is that you don't have much of a margin to work on the exhaust ports because of the aforementioned water jackets. Re-welding an iron is practically impossible or very hard\difficult anyway. That's where the porting limits reside. Custom sleeves could help, especially in a turbo'd engine. There's who runs sleeveless but the heat really stresses the irons. Definitely a big no if durability is a concern (and it is!)
The problem Ben is that you don't have much of a margin to work on the exhaust ports because of the aforementioned water jackets. Re-welding an iron is practically impossible or very hard\difficult anyway. That's where the porting limits reside. Custom sleeves could help, especially in a turbo'd engine. There's who runs sleeveless but the heat really stresses the irons. Definitely a big no if durability is a concern (and it is!)
I am very serious about making a motor in the near future to see if experiments work. I would be willing to loose some money on this in the name of research. Hell, it can even be done with a stock renny and not a ported one to see what happens.
I hear nothing but complaining about the limitations of the exhaust ports on the renny. Why not just make some additional small ports for the hell of it.
04-08-2010, 02:47 AM
#458
No side iron involved. I meant actualy adding a small port in the actual rotor housing itself where the FD exhaust ports normally are. Just a port big enough to help get a little bit more exhaust out. A new sleeve can be machiend and pressed into place. Sure it will make making an exhaust manifold a hassel, but it might be worth it, or it might be major fail. But we need to try first.
I am very serious about making a motor in the near future to see if experiments work. I would be willing to loose some money on this in the name of research. Hell, it can even be done with a stock renny and not a ported one to see what happens.
I hear nothing but complaining about the limitations of the exhaust ports on the renny. Why not just make some additional small ports for the hell of it.
I am very serious about making a motor in the near future to see if experiments work. I would be willing to loose some money on this in the name of research. Hell, it can even be done with a stock renny and not a ported one to see what happens.
I hear nothing but complaining about the limitations of the exhaust ports on the renny. Why not just make some additional small ports for the hell of it.
That's going to be fun to build though, as an experiment.
I am really curious to see the bridgeport dyno at this point, so that we can place this thread back in topic
04-08-2010, 10:51 AM
#460
NOTE:
This is still the factory engine. The attempt was to see the flat line increase between stock and bridge port.
Did the base map dyno last night... not promising. I think I may be loosing compression. We'll figure it out after Deals Gap. I'll have a compression check done on it, but I started having hot start issues even with the BHR coils on it this week, so between that and the loss of power, it kinda makes since to be loosing compression. lol... looks like I may have 2 fresh engines to work with.
Dynojet Inertial Dyno
HKS Hi-Power
BHR Ignition Kit
3rd gear pull: 161.69 HP 117.09 TQ
4th gear pull: 159.39 HP 124.93 TQ
5th gear pull: 164.71 HP 121.38 TQ
Any other opinions on these numbers? I see most people in the dyno thread running like 178~200 HP on DynoJets.
https://www.rx8club.com/showthread.p...hlight=dynojet
This is still the factory engine. The attempt was to see the flat line increase between stock and bridge port.
Did the base map dyno last night... not promising. I think I may be loosing compression. We'll figure it out after Deals Gap. I'll have a compression check done on it, but I started having hot start issues even with the BHR coils on it this week, so between that and the loss of power, it kinda makes since to be loosing compression. lol... looks like I may have 2 fresh engines to work with.
Dynojet Inertial Dyno
HKS Hi-Power
BHR Ignition Kit
3rd gear pull: 161.69 HP 117.09 TQ
4th gear pull: 159.39 HP 124.93 TQ
5th gear pull: 164.71 HP 121.38 TQ
Any other opinions on these numbers? I see most people in the dyno thread running like 178~200 HP on DynoJets.
https://www.rx8club.com/showthread.p...hlight=dynojet
04-08-2010, 11:47 AM
#465
I don't think so. All of the numbers I've ever dealt with that show comparative figures between piston and rotary point to the RE needing about 1/3rd more mass air flow to make simliar as a piston motor. I've seen it over and over and over again. If you'd like to have a good "concensus" with somebody about this, talk to Howard Coleman as he's got the math laid out pretty well.
B
B
I will give you few examples
All out racing 4-stroke from BTCC era (2.0 4 cilinder) was putting out 140 N.m of torque per litre(engine build for lowest possible friction losses), R26B in endurance trim has 116 N.m per litre. 83% of torque (I admit, assuming similar VE%). Such 4-strokes had BSFC as low as 0.4, R26B at best had .46, 13% higher brake specific... BTW R26B was classed as 4708 cc, 90% of actual comparable capacity.
Wankel engine isn´t that inefficient
04-08-2010, 01:01 PM
#466
BDC Motorsports
Howards math is based on one single number and doesn´t taking into account porting and other variables. Its good for getting into ballpark, but is letting huge amount of power on the table...
I will give you few examples
All out racing 4-stroke from BTCC era (2.0 4 cilinder) was putting out 140 N.m of torque per litre(engine build for lowest possible friction losses), R26B in endurance trim has 116 N.m per litre. 83% of torque (I admit, assuming similar VE%). Such 4-strokes had BSFC as low as 0.4, R26B at best had .46, 13% higher brake specific... BTW R26B was classed as 4708 cc, 90% of actual comparable capacity.
Wankel engine isn´t that inefficient
I will give you few examples
All out racing 4-stroke from BTCC era (2.0 4 cilinder) was putting out 140 N.m of torque per litre(engine build for lowest possible friction losses), R26B in endurance trim has 116 N.m per litre. 83% of torque (I admit, assuming similar VE%). Such 4-strokes had BSFC as low as 0.4, R26B at best had .46, 13% higher brake specific... BTW R26B was classed as 4708 cc, 90% of actual comparable capacity.
Wankel engine isn´t that inefficient
All of the numbers from the various compressor maps I've looked at vs. power output juxtaposed against fuel consumption (at whatever air/fuel ratio range) all square with the assertion that the motor consumes roughly 1/3rd more air over its piston counterpart, everything else remaining equal where it can. I noticed this 10 years ago on my first "big turbo" setup I ran on my 4-port turbo block with a Turbonetics 60-1 HIFI after I'd dyno'd it and got the setup squared away. This explains why we (as rotary folks) wind up having to run not only larger compressors but also substantially larger turbines to produce good power. Is it any real surprise? I don't think it is and I don't think the figures I've given are ridiculous.
B
04-23-2010, 01:04 PM
#469
Super Moderator
Yep bad things have happened to the OP...Philip.
Over the past year or more his car has had the engine out 4 or 5 times...lost count...with the shop in South Africa also giving him the run around.
He had the car back in his possession a few times, but the engine(s) did not last more than 50 miles.
Currently it is being put back to stock.
As far as I know the issues have been about the bridge size, losing an Apex Seal piece (need to use a one piece Apex Seal), and I think he had a corner seal problem in one of the rebuilds.
Over the past year or more his car has had the engine out 4 or 5 times...lost count...with the shop in South Africa also giving him the run around.
He had the car back in his possession a few times, but the engine(s) did not last more than 50 miles.
Currently it is being put back to stock.
As far as I know the issues have been about the bridge size, losing an Apex Seal piece (need to use a one piece Apex Seal), and I think he had a corner seal problem in one of the rebuilds.
04-23-2010, 03:11 PM
#470
we'll see what happens with mine.
I'm sure Brian planned out the ports so we wont have any issues with seals. I'll guess we'll see when I finally get mine together. The guy that was going to assemble mine was bit by a dog in the hand, so I have to wait till he recovers, and the other guy in town that could do it is busy for the next couple months.
So I'm kinda hanging till I can get someone's time.
Hopefully I wont have the problems that he's having.
I'm sure Brian planned out the ports so we wont have any issues with seals. I'll guess we'll see when I finally get mine together. The guy that was going to assemble mine was bit by a dog in the hand, so I have to wait till he recovers, and the other guy in town that could do it is busy for the next couple months.
So I'm kinda hanging till I can get someone's time.
Hopefully I wont have the problems that he's having.
04-27-2010, 09:44 AM
#472
The first pages are Philip. Towards the middle are a few other people discussing it, and twords the end is my slow build.
I'm not sure what you're point is really... If you had read my posts I lay things out pretty well as to how far along I am and when to expect dyno results. Not everyone has a lot of time or money to spend te get everything done next day.
You'll just have to be patient.
I'm not sure what you're point is really... If you had read my posts I lay things out pretty well as to how far along I am and when to expect dyno results. Not everyone has a lot of time or money to spend te get everything done next day.
You'll just have to be patient.
04-27-2010, 05:33 PM
#473
Super Moderator
Philip now has his 8 back to stock and running OK around South Africa.....