boostmotorsport

Ted,
Other peoples ignorance justifies you being a jerk to them? I dont think members should have to tip toe around you because they might make an incorrect statement, cuz if they do youll have a "big ****** problem" with it. You may have a lot of knowledge but you treat people like ****. If you treated people like that at a street races, or a track on a daily basis, youd be getting in fights pretty regularly!

suganuma

Ted, I think you need to step out, look back, and think about this. I can gleam from your posts and the information on the websites in your signature that you are a very intelligent person in respect to cars and thier related subjects....maybe internet design as well.....so bear with. Just because someone states something does not mean that they are an expert on the matter or claim to be. Obviously people read things on this forum, online, in books, etc and sometimes the information is not completely accurate. I wouldnt post if i wasnt asking for help. I am not posting to brag or claim that everything I say is without fault. If something I say is wrong, then correct it so that I know that its wrong. I was stating information that I had seen on this forum and also heard from other people with rx7s and similar setups. Not everyone knows everything you know. you didnt know all of what you know 5 or 10 years ago probably....you had to learn it somewhere....why not just simply pass on that information through this forum. It IS a learning resource isnt it?? thats what i come here for at least - not to sit in the lounge and look at pictures of some stuffed teddy bear blowing kermit the frog or talk about how my dad ran over my cat.

of the things you listed...
1) i know that
2) understand, but have never taken apart an external one to really look at it (i learn visually very well) - i would assume very similar to a BOV if i understand it all correctly.
3) How to read compressor maps - a friend of mine helped me to gain a general understanding, but am still learning and would like to learn how to better...
4) What A/R stands for - heard 2 different explanations and read 2 different things in a few websites.
5) How much air flow does a 13B do - dont know
6) Difference between boost and airflow - dont know what you mean by airflow....i am no engine expert

I have no problem admitting that I dont know everything. When i post a question, i try to address any questions and supply what information i know in the begining so that i can go from there or be corrected where i am wrong. so, all of these things that people dont know.....how about you help us all out and make a few threads about it all and give us some reference sources. there are GOING to be people asking questions b/c the whole world is not on your education level on every subject. THAT is the only ignorance that i see on this matter.

Obviously other people respect your opinions and the information that you do provide....shouldnt you give them the same respect back when you provide that information or correct any faults in their statements? I would think so.

---------------------------------------------------------------

NOW....can ANYONE give me information on a T61 with 1.00 exhaust. has anyone used this setup....know someone who has used this setup.....have dyno charts...ANYTHING??

TIA,

RETed

Hey, if this is going to turn into a personal attack on me, then fine.&nbsp It doesn't looks like you're totally comprehended what I wrote, so there's no reason to reply other than to defend myself.&nbsp It ends here on my part, as it does not contribute in any way to this thread.


-Ted

RETed

That reply wasn't directed at you - it was a reply to boostmotorsports.&nbsp It was a rant in general.

Since my comments have hit some kinda thorn for some people, maybe I should qualify my statements.&nbsp There are ways to get efficiency up on turbo power out.&nbsp I'd like to see a 60-1 put out 400RWHP (not 399.999) at 15psi (not 14.999) on a DynoJet (or equivalent) using a A2A FMIC with no other cooling enhancements.&nbsp A2W IC's (and any number of ingenious methods to cool the intake charge down) can easily cool to below ambient temps - hell, you can get it down to freezing if you want.&nbsp There's a lot of talk of I've-seen-blah-blah-blah - maybe we can get dyno sheets posted here for proof?


-Ted

gfelber

Actually, I think Ted is right. Particularly with regard to number 5. I challenge anyone to answer that for both stock ported engine and a street port. Heck, how about just a stock motor. Then show me where you obtained your VE data to perform the calculations.

I 've been trying to find this out for a while

Gene

boostmotorsport

Hes right when he said that most people on this forum dont know..... All I am saying is even if thats true it doesnt necessitate being a jerk to them for it. I wonder if he acts that way when he hears a incorrect/untrue statement about subjects other than cars. I am just tired of hearing him bash people just because he disagrees. hes just a lil arrogant in my opinion, knowledgable but arrogant.

SPOautos

Why does a rotary have a 20% handycap for a piston engine? Are you comparing similarly sized engines. I'm not saying it is or isnt I'm just asking why a rotart would have a 20% decrease in hp over a 2.6L piston engine with the same turbo and the same boost with all other things being equal like air temps ect...

Is it because a piston engine can breath more air? Well, I guess if they are the same size they should take in about the same amount of air?

Please explain Ted, you've got me thinking and now I cant work!!!!! Damn, you lol

STEPHEN

gfelber

Stephen,

The basic formula to calculate engine flow for a turbo application involves a number of factors:

engine displacement, cubic inches (D)
volumetric efficiency (VE)
max RPM (RPM)
displacement/rev (D_R)
conversion factor (1728)

thus:
D x VE x RPM x D_R / 1728

For a nonported rotary:
80 x .70 x 8500 x 1/1728 = 296 CFM (assuming my VE is correct!)

For a 2.6 liter boinger:
160 x .85 x 8500 (yeah right) x 2/1728 = 334

334= 12.5 % greater than the rotary's 296, but there is at least one other factor to consider (below).

Couple of remarks-
A piston engine only displaces half of its volume per revolution, while the rotary displaces all of it's volume per rev. That will change the 13B displcement from 1.3L to 2.6. I think rotary engines have a lower VE than piston engines (and used .7 versus .85), which might explain Ted's 20% estimate.

If this is true, however, then the 20% will diminish if the rotary is ported.

The other factor to consider is exhaust gas temperature which I think is much higher on a rotary compared to a piston engine.

Gene

machinehead

A few things.
One, I personally don't mind an attitude if I am getting something (good reliable information) out of the conversation.
Two, you still need to convert cfm to lb/min if you are going to use the info to read and plot compressor maps. They all show in lbs/min nowadays. But I think you calcualtions are right. I have in my mind something like 300cfm for a stock port 13b.
Anybody know how to convert cfm to lb/min?

RETed

It really comes down to the decreased efficiencies of the rotary engine versus a (modern) multi-valve piston engine.&nbsp Yes, I think it's related to VE, as gfelber pointed out.&nbsp As for reasons, take your pick:
*Decreased efficiency of the rotor combustion "chamber" versus the round combustion chamber of a piston engine - i.e. more complete burn in a piston engine.
*Relatively early opening of the exhaust port versus the piston exhaust valve timing - if combustion is kept longer inside the engine, the combustion energy has more time to "work" on the eccentric shaft/crank shaft.

As for engine displacement versus turbo, it really has nothing to do with engine displacement.&nbsp We're talking about efficient sizing for the engine displacement.&nbsp Try and compare identical turbo sizes for piston engine versus rotary engine.&nbsp For example...
*Mitsubishi TD-06SH on a rotary engine puts out barely 400 to the wheels.&nbsp This same turbo puts out 500 easily on a piston engine (i.e. Toyota 7M-GTE, Nissan SR20).
*Garrett T-66 on a rotary engine will make about 500.&nbsp T-66 in a big V8 (Ford 302) will easily make 600.



-Ted

gfelber

Uhh...who said anything about attitude?

A rough conversion for CFM to lb/min at ambient is to multiply by 0.069.

That's actually a poor approximation. To do it right you need to include the temperature (PV=nRT) at the intake manifold.

Rearranging, we get n=PV/RT

Formula (using degress Rankine/absolute temp) is:

n (lb/miin) = P (PSI) x CFM x 29/10.73 x DEGR

where P is absolute pressure at sea level (boost in PSI + 14.7), 29 and 10.73 are constants, and DEGR is degrees Rankine (deg F + 460)

Gene
www.purplemantis.com

Rutt

Ted.... I'd like to see the answers to your questions since we are ignorant. Especially the meaning of A/R since there are 40 biliion interpretations of it floating around.

relvinnian

I haven't read this whole thread, I will later.

As I stated in the thread linked above, there is always a compromise. You can easily make over 400rwhp @ 15 psi with a 60-1 compressor. These dynos you see of 350-385rwhp are normally on "standard" street ports (ie. cleaned up rew ports), running .96-1.00 housings. If you run a very LARGE street port (ie. making peak power 8.5-9k) with a 1.24-1.32 housing, I garauntee people would see more than 400rwhp @ 15 psi.

That's generally not the point of the turbo. People pick it because it spools quick.

RETed

I give up too much information as it is.&nbsp I base my business on people not knowing this information, and this can quickly turn into a thesis-length discussion on those topics.

All I can recommend is get the Hugh MacInness "Turbocharging" and Corky Bell "Maximum Boost" books.&nbsp These answer 99% of the questions on turbochargers.



-Ted

SPOautos

Why is it that in the formula D_R is "1" for the rotary and 2 for the piston??? I'm trying to get a good understanding of this

Thanks,
STEPHEN

RETed

gfelber put in a comment in his "Couple of remarks-" section, but you might not have caught it.

What we are trying to figure out is displacement.&nbsp For a piston engine, displacement is calculated by piston area X bore.&nbsp Now, this "displacement" is "expelled" (as exhaust) or "inhaled" (as intake) ONCE per two revolutions of the crankshaft; this is the definition of a 4-stroke piston engine&nbsp Therefore, to extrapolate this equivalent to the rotary engine, we need to take into account what a rotary engine does in two revolutions of the eccentric shaft.&nbsp This gets tricky, as you have differing opinions on how this should be considered "equivalent".

Some rotary engine facts...&nbsp The rotor, itself, spins 1/3rd the speed of the eccentric shaft.&nbsp Therefore, two revolutions of the eccentric shaft only equal 2/3rd's of a revolution of the rotor.&nbsp A rotor "swept" volume = 654cc for a 13B.&nbsp The front-to-rear rotor relationship is 180&176 out-of-phase; an "adjacent" rotor face front-to-rear is actually only 60&#176 out-of-phase.&nbsp To "reference" the eccentric shaft to rotor position, we shall use the front rotor.&nbsp Therefore, for two revolutions, the front rotor should spit out 2 rotor faces, which equate to 654cc x 2.&nbsp Now, this comes the interesting part - while the front rotor face (RF) is referenced at one apex seal (AS), the rear rotor is in the *middle* of it's exhaust; while the front rotor goes through AS-RF-AS-RF-AS, the rear rotor goes through RF-AS-RF-AS-RF!&nbsp This means the rear rotor begins and ends in a middle of an exhaust output.&nbsp So how do you count this?

One method - the front is obviously 654 x 2 = 1308cc.&nbsp The rear would count as 654 x (0.5 + 1 + 0.5) = 654 x 2 = 1308cc.&nbsp Adding front and rear gets you a 2x multiplier of 1308cc as equivalent displacement (2616cc).&nbsp This is where the 2.6 liter number probably comes from.

Alternate method - the front is still the same at 654 x 2 = 1308cc.&nbsp The rear would count as 654 x (1 + 1 + 1) [how can you get "HALF" an exhaust output?] = 654 x 3 = 2562cc.&nbsp Adding front and rear gets you a 2.5x multiplier of 3270cc, which a lot of our piston engine'd racing opponents would love to get the 13B rotary engine bumped up to.

Bottom line, it's hard to get a definite answer to this question, but our original questions is referenced from the first method.



-Ted

blackscorpio

I think with all the discussions on engine displacement we no one is answering the original question t-61 vs T60-1? Which is better unser what application?

gfelber

Good catch!

My bad. Should be .5 for piston and 1 for rotary.

Gene

gfelber

Oh yeah

I was trying to illustrate that one should know VE/displacement before deciding. This will certainly affect turbo selection, particularly for a ported motor versus stock.

Once you do this, take a look at the compressor maps and decide which is best for you, e.g., do you want better spool up, higher peak HP, etc.

Gene
www.purplemantis.com

spyfish007

The odd shape of the rotary contributes to the fact the rotary has poor THERMAL efficiencies. I think you are all at least a little off on your VE conversations-you need to talk to RiceRacing. (at least clarify the VE to porting etc) One other note VE is not the same for all RPMs!

gfelber

You're exactly right- on both counts. And yes, VE changes with RPM. I was using .70 for a stock motor at 8,500 RPM. I have read that ported motors will approach 100% VE (depending on port type and RPM, of course), but can't find anyone who actually has these data.

Rice Racing in AU? Can you provide contact info?

Thanks-

Gene

suganuma

can you dumb this down a bit (i.e. give some numbers and info without the theory) and use as an example the compressor maps that I linked?

i really just need some info pertaining directly to the turbo applications i listed and then I will go back and sit and figure everything out to make sure i understand it using my application as a pertinent worked out problem/example.

thanks,

Nic

machinehead

gfelber, my remark about attitude was not directed at you, I was defending Ted. And thanks for the formulas.
So if we take your general number of .069 then 300 cfm becomes about 20lbs/min. double that for running 15 psi of boost and we get 40lb/min which is right in the peak efficiency range of the 60-1 with some room to spare. So basically unless you are going to run 30psi then the 60-1 is a good compressor for the 13b. Its good on paper and in real life, which is probably why it is so popular.
What I can't see however are any drawbacks to the T61, other than the price. It seems like it will do everything the 60-1 will do but it will also allow you to run higher pressure levels if you want.

Maxthe7man

Spyfish beat me to part of my intended response, but what also I was going to add is that extended overlap of the engine will increase the general CFM intake of the engine..
Although the calculations are rather sexy seldom do they hold water in the real world, even on a 13b na I have measured over 350 cfm moving through the intake tract...
To compensate for overlap and wasted inlet charge, the VE should actually be increased over 100%, not decreased..Max

Kurgan

Pertaining to the actual topic of the the thread:

Ok, for starters, here is Brian Cains dyno. He is running a 60-1 hifi with a .96 undivided hot side with an undivided cast iron manifold and an air to water intercooler which is VERY effecient... (just like ted said several posts back, but I thought I would reiterate). This run was made at 17psi and obtained 424 rwhp:



Now, I know for a fact that Don Marvel made a 13B-rew with a 60-1 (with a small A/R) make 435 rwhp at 4500 rpms, but it died off after that and ended up making about 390 at 8000 rpm. They changed the compressor wheel to a 63 series and was able to get in the 480 rwhp area, but I don't know the exact number or rpm, but I would estimate 5200 rpm.

That same engine, when switched to run alcohold, ended up putting out 519rwhp at (I'm trying to remember the RPM here, I know I have the hp right) 6000 rpm.

Maybe your engine builders just don't know how to port for the turbo you are going to be using.... Don is able to take a turbo, its specs, and somehow design a port configuration and style in his head that will optimize EVERYTHING for the car... these ports were made for a lower A/R (I think it went on a sand rail... but I may be wrong here).

You want power and range like you stated, you need to get in contact with a god of rotaries like Marvel.