http://forums.freshalloy.com/ubbthre...=&fpart=1&vc=1

i beg to differ.

also i believe that i am the reason the SC61 is being made by precision. I specifically asked them for a 6 blade wheel that will outflow a 60-1 (on par with a t61) and using more modern center sections/turbine wheels.

be glad javier is a nicer guy than i am, he can help you quite a bit.

 

I would use something a bit more accurate like laboratory grade digital temp sensor because those GM ones still won't give you the accuracy you're looking for. Also for density you need to figure in the humidity. Say a digital humidity gauge that picks temps too would be better.

Flow-benches from what I can tell just measure the amount of air they can pull through a head, manifold, or whatever you need to find the flow of. I believe they work by calculating the vacuum against the actual amount of air they pull through, but I'm not too sure on this. I do know they don't check humidity or temp because they are usually sealed and in a controlled enviroment. Hence the reasoning they aren't the best way to predict performance of any given part. That and flow has nothing to do with air quality. You could just adapt a fan to calibrate for the settings if you want to do all the extra work. Otherwise just get the voltage/flow maps from the manufacturer.

Mount MAF's are the ones in the tubes like on the Mustang's, Supra's, and F-bodie's. Un-mounted ones are just that, they aren't in any particular housings. They are like $56 when I bought mine like 2 monthes ago from Honeywell. It's the same MAF used in the Pro Street Manta-Ray bodies 'Vette, but no housing and a lot cheaper. It came with the voltage/flow map in the box when I got it.
I've been working with MAF's for a while now. They're just better. I'm running a guinea pig management system though.

edit: This is my last post till tomorrow, but some people here have a bit too much of an ego for me. I say if you want to be better than any one or think you are, help them they will get the hint, and eventually start acting differently.
I'm not one to talk though. I refuse to help anyone that's been a ***** to me from now on. I'll help any new ******, but the old ones are too ignorant to deserve my respect. I don't need them. I can do it myself, and I will show you who actually knows what they are talking about. Those of you that in this group know who you are. Everyone else I'll be more than willing to open my mind for you. I'm a little sick of this childish BS I've been shown lately. Some people are just plain stupid, and can't be help except with a shotgun.
Sorry OT rant to someone that's a member here.


[Modified by Zero_son, 2:23 AM 2/21/2003]

 

that was after the thread you and i and everyone else had our arguments over. I created that thread because you used the mentality that the 60-1 was the best overal because its already made so much power on these smaller 4 cyl. motors.

I'm not worried about outflowing the 60-1, i've never seen one choke on any motor. I'm worried about its efficiency in comparison with another compressor at the same boost level. my MAIN POINT was that if you chose a compressor that showed higher efficiency at a PR vs airflow than the 60-1 that you would make more power. PURELY THEORY at this point.

i'm not flaming here, i'm here for sharing info. i was really pissed when i started that thread becuase there wasnt any sight of you seeming to listen to our side of the debate. But thats in the past. I appologize if that angered you that i dont fully agree with you and then made a thread about it. I think i called you a couple names and i appologize for that.

But your train of thought made me think a new way of sizing, so i must ask the questions which i have above in detail. now i just need to get this 50trim on the motor and on the dyno and see if it chokes at 15psi like everyone says its going to on a high flowing setup. If it does, i'll be wrong, you will be right.

 

sounds nice

well have a fully built sr20det in the shop with a sc61, and a stock sr20det with a 60-1. im sure that at 19psi we will have more than 330 whp.

the nissan people hate to hear this, but they have a lot of catching up to do, in regards to turbos on 4 cylinder motors. All cars are basically the same, regardless of what factory they came from. Hondas have had a lot more time thrown into them as far as hard core drag racing goes, and my *entire* argument was that there is no way a 50 trim will make more power than a 60-1. I didnt say the 60-1 would have better response, or anything. Like chris said, if you have a 50 trim, and he has a 60-1 you will get walked. The guy who had his 60-1 make lower power numbers had a car that wasnt runnign properly.

CFM is CFM, and airflow makes horsepower. If you have a bigger turbo, that flows more air, you will make power (assuming you are capable of spooling the turbo).

Big turbos work well on 4 cyl engines with high flowing cyl heads. If youre drag racing, use a bigger turbo than a 50 trim. There are no turbocharger formulas i have seen that adequately suit the sizing that i much prefer to go with. All the formulas will require you using a turbo that is maxxed out prematurely (in drag racing). Glad to see you opened your eyes.


btw: telling me " you people can $&#*$#& off " is a bad way to make friends.


[Modified by FFgeoff, 10:11 PM 2/20/2003]

 

I havent opened my eyes because i cant see the facts in the sizing choice. it will be proven to me if this 50trim chokes at 15psi which is where my max boost will be at on this motor. 357rwhp got me 11.39@119 400 will get me deeper 11's.

I never had a map for the 52trim of the GT3037s turbo. so i never could bring arguments to the table. I've always used the GT series turbos and never could see maps.


as far as the catching up thing, i'll accept the fact i have alot to learn. just help me learn and i'll listen. I dont have the money to try different turbo setups which is where people seem to be getting their sizing recomendations from, not from math(which can only go so far)

 

once again, the nissan guys copy us.

We popularlize the T3/T04e, then we move on to 60-1's, now were on the SC61 and look who wants a link?

 

theres no copying going on.....i had been using a GT3037s for about 2 years and loved it. the SC61 is a 56trim GT compressor which is a step up above the 52 trim the GT3037 uses. the fact that i can get it with a bigger turbine is what appeals to me. if i was copying i'd have a honda, not a 89 240sx. if you could only see the 89 civic hatch back i had as a play toy.....it happened to be LIFTED for various reasons.......

i see your and raise you a

 

hehe...i might be the first nissan person to use a SC61
from what ive seen, most nissan people like their smaller streatable turbos and most honda people like the larger turbos.....different driving preferences i guess.

 

could it be that the hondas are running higher CR ratios?

 

its mostly that most nissan guys are still "sizing" turbos. When you size a turbo, you are basically selecting a turbo on the maximum it is capable of outputting.

i disagree with this method, and the few nissan guys who have strayed from the pack (louis's buddy ben comes to mind) have made much more power then their peers.

honda guys have been at it for a long time, and 5 years ago, i thought a t04e 60 trim was too big for a street car. Now a 60-1 is a bit small for a street car

 

nah they dont copy us, they are just a bit behind the times. most are too narrow minded to open up their eyes to see what the honda ppl are doing. I remember when i was first getting into turbos, i spent most of my time lurking on the grand national boards.

There is no reason i can think of that a well built nissan couldnt clean up on any honda out there.

 

the age ol battle
nissan=torque and wide power band...yadda yadda yadda

:edit:
on a side note, maybe i can have datalogging with out a stand alone
http://www.ashleypowers.com/Data%20Acquisition/daq.htm



[Modified by javierb14, 10:40 PM 2/20/2003]

 

that looks like a pretty nice system. Autometer's is way overpriced, but you may want to check out the stuff that Holley has to offer. i had a buddy who used to have it, pretty decent.

 

supposedly it plugs into the diagnostic/consult port, then uses a program similar to LabView....should be easy to use.

 

you guys are stereotyping me with :
5 years behind
part of the nissan crowd who sizes turbos

please stop making assumptions about me and stick to the questions, if you cant answer them or prove me wrong(im ASKING to be proven wrong i'm not being a smartass)......well you know.

its a freaking turbo, its an interal combustion motor and RPM.....i dont understand why the two trains of turbo math arent being even talked about. (calculated N/A airflow= engine size x RPM / 1728 x 2 ..... AND .....hp to airflow rates)

1. SOME one has to be looking at maps.
2. SOME one has to be choosing a compressor for a certain application.


tell me how you guys ....javier and jeff are choosing. pick a motor, a hp goal, a boost level and tell me how you pick a compressor. PLEASE. or tell me you've seen someone put a 50trim with a O trim T4 in a divided housing with a 2.0 liter motor, spinning to 7600rpm @15psi and it chokes. nothing more, nothing less.


[Modified by Greaser, 7:11 AM 2/21/2003]

 

i used to calculate tons of formulas. i used to try lots of stuff out, all i ever found out was that the only turbo that would work on a GSR is a 50 trim or a 54 trim.

When my friend told me 5 years ago a t04e60 trim with a stage 5 wheel was going on his race car, i said wow thats gonna be laggy! It wasnt. That was the same turbo that was passed onto me, and then passed down to jaime farrer.

After realizing these turbos were still too small, i gave up the formulas we had, and started looking for more. Everything else gave me similar results.

So then i realized that rather than sizing the turbo to the engine, its easier to size the turbo to the CFM, to the engine, to the HP level. From there i started simply figureing out a power level i wanted. I picked a turbo that flowed high efficiencies at that CFM level, of course right outside of max efficiencies, and got a vague idea of the turbocharger's behavior.

Now, if i am gonna size a turbo, i very rarely start from scratch. We know what the engine (in this case sr20) is capable of, we know how much power we want to push with it, and in the case of javier's car lets say he has his sr20, greddy cams etc. We want to do 600 at 28 psi or so. The sc61 is efficient to almost 30 psi its 79% efficiency island is HUGE horizontally, and the 78% is plenty fat, too.

1.8 bar and 55 cfm is plenty healthy, this is an ideal place for the sr20 to operate.

so figure out realistically what the motor can push. Find a turbo thats more efficient than 75% in this area and run it.

If youre going with a 50 trim t04e, going to a t4 exhaust side will certainly evacuate more exhaust, but there is going to be a price. Based on what ive seen, this would work, but not well enough.

 

and or converse with garrett engineers.....believe it or not, they dont all agree

 

thats how i've come up with several choices....say i want 400hp at 15psi, thats gonna need 450crank HP so i look for a map with point on the right side of high island at 45lb/min at 2.02PR. This makes the 50trim choke. Which i fear with a passion. I look to my old compressor map GT3037 or 76mm 52trim and 45lb/min @ 2.02 is a little past high eff. but still good. The 56 trim is PERFECT.

Then i think, holy **** if the motor is gonna operate there then it'd have to be at 122% VE. some people alot smarter than me are telling me theres no way a SR is operating VE that high. but the "50trim is too small". when i ask why they cant tell me.

thanks jeff. if this 50 trim chokes then i'll start to use this method of choice. but can we both agree this method would be on a high flowing drag car? not a stock motor'ed 3" exhaust no cammed street car? Through my years with the GT3037 i've made 321rwhp, 357rwhp, and 392rwhp all at 15psi. this is why all the VE questions.

 

what did u change about the set up between all those #'s if they have the same motor and the same turbo?

 

GREASER- Your making life more complicated then it should be. If your building a street car, whats with all the math? Its not rocket science. Judge a turbo by its CFM and that should tell you what the tubo is capable of hp wise. Compressor maps mean nothing. There are a tons of motors out there that can run a 60-1 for example and all come out with different hp numbers because of the motor. You need to put more effort in your engine so you can meet these goals without stuffing a big turbo under the hood to compensate where your engine lacks. 400whp is big power for a street car, so having a strong efficient foundation ensures reliability. Just because you make 400whp doesn't mean your whole setup is efficient. Just food for thought.

 

321rwhp: completely stock SR20DET, FMIC, 550's, TEC II, HKS GT3037s, HKS wastegate, Log manifold, 3" DP to 2.5" crush bent piping exhaust
357rwhp: added JWT S4 cams, Greddy Intake Manifold, 2.5" HKS hyper exhaust
392rwhp: added 9:1 pistons and crower rods, dropped exhaust

funny thing about this is i'm now at the 357rwhp setup, the built setup lifted the head and i havent fixed it yet on that motor. so i went from 321rwhp to 392, then put another motor in with the mods i have with exhaust and pulled 357rwhp. but we're only talking about 15psi. i've gone to 20 on the dyno and on the track.

 

i'm making it complicated because i'm unsure. People are expecting me to have heard of all the testing that has gone on over here. i havent.

if i did this i'd have a Y2k or a T91 on my car. why cant i run that?

its not the motor, its the mods to that motor that change the breathing capabilities of the motor.

i think you should look a little closer at the specs of my setup. its a very efficient setup. we're talking about 15psi here. NOT anything higher. 400hp @15psi is highly efficient in my eyes. this is not full drag car, but not really a street car. i dont have the money to compete in pro classes. and if i'm overthinking everything dont you think i would have thought of what you just said?

i race with people who wonder why i limit hp. I do it for reasons that others may see as stupid, but for me; they are all right. save parts, get ALL my hp to the ground with 1.5 60ft's, car can run cheap pump gas. i'm not asking you to judge me. i'm asking to advise on correct methods of turbo sizing. and people are starting to help. i'm not stupid, just point me in the right direction if i'm not going there.

 

Holy snap, Brah, you didn't have to pick my post apart man. Why don't you call Precision Turbo and talk to Harry, tell him what you have and ask him what turbo would achieve your goals at your desired boost level? Bet you any money he won't pull out a math formula to answer your questions, because its something he knows (and he will have your answer within seconds). I never had to ask Harry all those math questions, and he has always got me where I wanted to be(650+whp in my full wieght street GN). All those mathematical formulas are just assumptions, and can very easily lead you down the wrong path. No flame intended, but you seem like one of those guys any shop would steer away from doing work for. Because you would challenge their knowledge with mathmatical formulas. Read all the posts thus far, and find the most common factor, and thats common sense. many suggestions have come your way, but because it didn't come in the form of a mathmatic equation, it was ruled as garbage to you.

 

I broke it down for easy reading.

I dont care what you think about me. i'm asking questions. I dont want to have to call people to ask what i should run. i want to learn on my own. my previous methods are being proven wrong and i want to find out why. is that so hard to understand?

 

when you size the little turbos according to their output, the 50 trim is working overtime to put down 450.

In my opinion, if youre drag racing a built 4 cyl motor, run a turbo sized like the sc61. that is a drag racing turbo. You will go low 10s with that turbo, and on slicks and if you learn to shift a bit quicker, the car will touch 9s.