Exhaust Manifold Comparisons (need input and suggestions)
#51
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Originally posted by RICE RACING
Thanks for hosting, that was damn quick!
Thanks for hosting, that was damn quick!
mike
#52
Banned. I got OWNED!!!
Originally posted by j9fd3s
no prob. i see you're still using the metering oil pump?
mike
no prob. i see you're still using the metering oil pump?
mike
I love PP's but I remember how much I hated them too (noisy, ridiculous fuel economy, go like **** when restricted) ! Good old love/hate thing going on in my head
#53
Hey Pete for the pressure wave tuning calcs do you treat the turbo end as an opened ended pipe or closed?
BTW that manifold looks very nice cant wait to see the rest of it!!
Isnt the exhaust wheel a bit small?.......
BTW that manifold looks very nice cant wait to see the rest of it!!
Isnt the exhaust wheel a bit small?.......
#54
Banned. I got OWNED!!!
Originally posted by shinjuku
Isnt the exhaust wheel a bit small?.......
Isnt the exhaust wheel a bit small?.......
It's bigger than a Greddy T88 Turbine!, much bigger than the HKS T51 turbines (SPL & KAI).
It measures 78mm at the minor dia, that combined with a 1.22a/r should flow reasonable enough sized the WG so it will by pass no more than 30% of the mass flow through the engine so Ex manifold to In manifold pressure ratio will be quite low & well below 1 with the right exhaust system.
#55
Banned. I got OWNED!!!
Originally posted by enzo250
Nice Job Peter.
It's good that you got the wastegate in direct flow of the exhaust gas. VERY IMPORTANT! Most people overlook this when they build there manifolds and then wonder why they can't control boost.
Nice Job Peter.
It's good that you got the wastegate in direct flow of the exhaust gas. VERY IMPORTANT! Most people overlook this when they build there manifolds and then wonder why they can't control boost.
I found this out with my older style manifolds, the new one has a lot of detail that does not come out in the photo's but at the junction of the WG pipes the angle is shallow and the entries are eliptical in shape allowing a good length of time to establish flow into the WG runners, along with all of that the junctions are at points near "branches" that deflect some of the exhaust gas to the WG. See how she goes soon enough
#57
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It was a 13BRE Cosmo engine with a large race/street port. As soon as I changed turbos the whole setup just came alive. It was a night and day difference. The turbo you have (same as what mine was) looks big and awsome but it just does not spool very well. You might get around that with manifold design but I just wanted to let you know what I went through so you could have a different option.
#59
so when i build me my manifold, i should do the manifold to wastegate ( to make the wastegate to be directly in the way of the gas pulses) then build the turbo to wastegate runners, would that be better to control the boost? it'll be alot of restriction to the turbo, but the control should be great right?
#61
BDC Motorsports
Thread Starter
Originally posted by J Oliver
It was a 13BRE Cosmo engine with a large race/street port. As soon as I changed turbos the whole setup just came alive. It was a night and day difference. The turbo you have (same as what mine was) looks big and awsome but it just does not spool very well. You might get around that with manifold design but I just wanted to let you know what I went through so you could have a different option.
It was a 13BRE Cosmo engine with a large race/street port. As soon as I changed turbos the whole setup just came alive. It was a night and day difference. The turbo you have (same as what mine was) looks big and awsome but it just does not spool very well. You might get around that with manifold design but I just wanted to let you know what I went through so you could have a different option.
B
#62
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Originally posted by 600HP CLUB
so when i build me my manifold, i should do the manifold to wastegate ( to make the wastegate to be directly in the way of the gas pulses) then build the turbo to wastegate runners, would that be better to control the boost? it'll be alot of restriction to the turbo, but the control should be great right?
so when i build me my manifold, i should do the manifold to wastegate ( to make the wastegate to be directly in the way of the gas pulses) then build the turbo to wastegate runners, would that be better to control the boost? it'll be alot of restriction to the turbo, but the control should be great right?
#63
Banned. I got OWNED!!!
Originally posted by 1Revvin7
That manifold looks nice Rice Racing, any plans to duplicate it? What are you ideas for a 3 rotor manifold?
That manifold looks nice Rice Racing, any plans to duplicate it? What are you ideas for a 3 rotor manifold?
In regards to three rotors, its hard!!! tuned pipes are great for the equal performance of each rotor, but the energy loss of the pulse before the turbine wheel is still hard to overcome.
This is why it is fantastic if you can either run a single turbo for each rotor or a turbo that has a divided housing which will make the most of the "free" energy.
There is not much you can do? Just make them equal length but still you will need to run a smaller exhaust housing because you will not be able to harness the power of the pulse to full effect as it is being "dilluted" before it hits the exhaust wheel.
It realy is amazing how big a turbine can be run when you use the exhaust pulsing to it's full potential, this same principle can be applied to straight 4 cyl engines where groups of two cylinders fire at once and each pair is fed into each seperate runner of the exhaust housing, the turbine combination I am using worked great on a 4cyl 1.5lt engine which reved to 10000rpm (power band from 6500 to 10000rpm) max, so with 2.6lt and 9000rpm plus stronger pulsing of a rotary there realy is no problems.
On a side note to BDC, I saw a piston example of the problem you are facing. this guy put on a fairly large divided housing turbo and the thing would only start to make boost in second gear and reach 10psi in 3rd!!! He swaped it out for a tuned split pulse header (grouped 1&4 and 2&3 into each runner of the turbo)and the thing started to hit full boost in first gear !!!!
It makes a massive difference and only some engines is it possible to be used to full effect, of which a 13B is one....so use the power thats there, its FREE and it will be a totaly different machine, you get the benifit of using a low restriction/pressure turbine combination while retaing the instant responce offered by harnesing the power of exhaust pulses to full effect
#67
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that would cost you 4 times the price of a normal T04 sized beasty, and i very much doubt that the gains to be found would offset the extra expense
#68
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Originally posted by 50tooslow
Rice what are your thoughts on running two smaller dual ballbearing turbos? Would this be benificial vs. running 1 large turbo.
nick
Rice what are your thoughts on running two smaller dual ballbearing turbos? Would this be benificial vs. running 1 large turbo.
nick
The problems are numerous though, assosiated plumbing of exhaust and intake delivery and discharge pipes could very well negate some of the performance gains, though spool rate at lower revs would be better for sure due to lower inertia associated with two smaller units.
The plumbing is a major nightmare and side issues related to heat shielding and inadequate space would become real issues that would reduce the performance of this set up compared to a well layed out large single turbo, it is very easy to loose gains by having to have a very tight series of bends to fit in a DP just as many bends to fit in the discharge pipes + have air filters located of convoluted pipes going to the compressor intakes, all of these things cause pressure drops and loss of efficiency and performance, not to mention the heat build up and radiated heat to other components increasing heat soak and further decreasing performance. Every twin "single" turbo set up I have seen in an RX7 engine bay has been a massive compromise and a non ideal situation with one or more elements having to be compromised.
I looked long and hard at doing this myself, and I chose to do the very large single for my target range of engine operation 5.5k to 9.5k rpm it will be just as responsive as a twin set up, and will be more efficient.
On a side note, this same issue was struck by F1 4 cyl engine runners in the early to mid 80's Hart, BMW, Zakspeed, The majority of which most chose to use a large single after trying to install the twin set ups in a chassis and experiencing heat realted issues, and performance losses due to the reasons I eluded to above, they got over the responce issue of a massive single by using the optimum header design which helped a great deal. The only one to try twins on the 4cyl was Alfa Romeo and the engine was a disaster, the prototype car actually burnt to the ground in one test session and it never actually raced. There are other good references to how much benifit a group split pulse tuned header works, there is a good old book called "turbochargers" by Hugh McInnes and in it they detail a BMW engine that was the precursor to the BMW F1 4cyl turbo engine and the differences between running a simple log manifold and running a manifold like we have been talking about, the differences as noted by McLaren engines was amazing!!! The engine went from having quite large lag to being virtually non existant simply by using the power of grouped pulses to increase turbine resonce, they noticed a VERY large increase in power too.
I know people hate refering to the 13B like a Inline 4cyl but as far as the basics go the same principles can be used (exhaust pulsing) and even greater effect on a rotary as there is more energy available
Twins technically are the ultimate, in practise there are many issues that will make it hard to realise the full potential.
#70
Banned. I got OWNED!!!
Exert from the book Turbochargers. Page 112 Intake & Exhaust Tuning
Basic summary of log manifold v's tuned length header on BMW 4 cyl 2.0L IMSA Engine of very ealry 80's.
Log manifold = 540bhp
Tuned headers = 600bhp
"Gary went on to experiment with axially divided turbine housings, an available option from most turbocharger manufacturers, he found that if the exhaust pipes were connected to the seperate sides of the divided exhaust housing so the exhaust pulses entering each side were evenly spaced, throttle responce improved even more. though this arrangement did not add power (over the tuned header v's the log) "turbo lag" was all but gone"
They go on to descibe how a similar principle is used by some road racing V8 engines but due to their firing order need to have pipes going all over (from left to right banks of cylinders) the place to achieve the even pulse spacing to use a divided exhaust housing to it's greatest advantage.........go on to say that some of the worlds quickest road racing cars use this arrangment to improve response out of low speed turns.
I think the key thing here is try to make the pipes the same length and keep the front and rear rotor pipes seperate into either side of the divided housing and you will have fantastic results, with minimal "lag" to boot
Basic summary of log manifold v's tuned length header on BMW 4 cyl 2.0L IMSA Engine of very ealry 80's.
Log manifold = 540bhp
Tuned headers = 600bhp
"Gary went on to experiment with axially divided turbine housings, an available option from most turbocharger manufacturers, he found that if the exhaust pipes were connected to the seperate sides of the divided exhaust housing so the exhaust pulses entering each side were evenly spaced, throttle responce improved even more. though this arrangement did not add power (over the tuned header v's the log) "turbo lag" was all but gone"
They go on to descibe how a similar principle is used by some road racing V8 engines but due to their firing order need to have pipes going all over (from left to right banks of cylinders) the place to achieve the even pulse spacing to use a divided exhaust housing to it's greatest advantage.........go on to say that some of the worlds quickest road racing cars use this arrangment to improve response out of low speed turns.
I think the key thing here is try to make the pipes the same length and keep the front and rear rotor pipes seperate into either side of the divided housing and you will have fantastic results, with minimal "lag" to boot
#71
Peter is absolutely right. I have built many turbo headers for 4cyl engines and you would be surprised how big of a turbo we could use when the turbo has a divided housing and the header groups cyl's 1&4 and 2&3 together into the housing.
I will be building a header for my rotary soon and will use a divided housing to help spool my monster.
Here are some pics
I will be building a header for my rotary soon and will use a divided housing to help spool my monster.
Here are some pics
Last edited by enzo250; 05-25-03 at 10:32 AM.
#74
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Let me ask this question. If for example the desired turbo isn't available with a divided housing, would fully divided manifold with equal lengh runners etc benfit the turbo. Or does not have a divided turbine housing ruin any and all benefits of keeping the pulses divided for the length of the manifold?
My hunch says this would be better than a collected unequal mani, but can any one verify this?
My hunch says this would be better than a collected unequal mani, but can any one verify this?
#75
Banned. I got OWNED!!!
Originally posted by carx7
Let me ask this question. If for example the desired turbo isn't available with a divided housing, would fully divided manifold with equal lengh runners etc benfit the turbo. Or does not have a divided turbine housing ruin any and all benefits of keeping the pulses divided for the length of the manifold?
My hunch says this would be better than a collected unequal mani, but can any one verify this?
Let me ask this question. If for example the desired turbo isn't available with a divided housing, would fully divided manifold with equal lengh runners etc benfit the turbo. Or does not have a divided turbine housing ruin any and all benefits of keeping the pulses divided for the length of the manifold?
My hunch says this would be better than a collected unequal mani, but can any one verify this?