ok, i’ve read a lot of the postings here and on other boards. i also went to a performance shop yesterday to get more info …and got my first baseline dyno run for my car.
so here are my questions…and b4 you tell me to search, i’ve listed why i need more help in figuring on the right turbo to get. thoughts and opinions please.
1 - ball bearing or non?
read about non-ball bearing being servicable and that being more beneficial. but the benefits of ball bearing being faster spool up.
not quite sure. I saw a 18g turbo start to spool up around 2.8k rpm yesterday on a dyno and if i remember correctly it reached its max low to mid 3k. not ball bearing and seemed to be sized right for the application. but…i don’t know…what am i missing here?
2 - water cooled turbo?
i’ve read the argument that it’s not necessary on smaller hp projects. but then the question i have to ask is why is it that oem turbo’s have it? and isn’t the elimination of a turbo timer reason enough…besides the longevity of a mechanical part due to heat break down?
3 - port inlet/outlet and blade clipping?
with better cfm…i am assuming faster spool…but i reserve the right to be wrong. will that do much to top end power? and will that possibly push the turbo out of its efficiency range?
4 - internal/external wastegate?
most kits have external, but i have been told it is meaningless on low hp applications and more about kids who want bling bling in the engine bay.
ok…yeah i should have mentioned…but i wanted to start out with theoretical questions. i didn’t think that most of them were engine specific. plus i like to learn.
its a scion tc 2.4L 4 cylinder (camry engine to be exact)
goals: start at about 260whp, learn about forced induction, learn more about my car, have fun driving…have an ‘efficient’ system that will scale (efficient to me means meeting my goals economically, not too much, not too little…but i don’t mind getting the right thing if it will be useful in the future…but not if it’s just fluffy bling…although fluffy bling sometimes has its’s place…but now i am digressing…so back to the goal list), so a year down the road when i want to add more power i can work with many of the components and figure out what i need to add/modify/delete, learn s’more, um beat the guy who cut me off to the next stop light…how’s that?
well, the thing is this. if you are looking for a cheap build with respectable gains, go very basic. non-ball bearing cheap rebuilt T3 would do the trick. now if you want the ability to take steps forward without having to constantly upgrade parts(waste money), buy a good turbo up front. with a engine size of 2.4, without specifically plotting a compressor map…a garret GT30r would probably suit the motor VERY NICELY, and support up to 500 whp in the future. the 30r is dual ball bearing for quick spool, and uses T3 exhaust flanges. it is also water cooled, which is a great feature because it helps eliminate baking oil in the turbo, esp. if you arent running a turbo timer and you wont have to let the car idle down all the time unless you were really gettin on it. for starters…read the how-to posts by zerodaze back in the technical section before you came into this sub-forum. he has a how-to on plotting a compressor map to size a turbo to your motor. that should be very helpful. another option is the sponsor on her DEZOD motorsports offers a bolt on kit for the Tc that has netted some pretty awesome gains. a good book to read would also be “maximum boost” by corky bell. its very in depth and technical…a great read for a noob, however it will take some time to read lol, its kinda a big book.
BB turbos do spool fast but most of the time you will find people (even race car drivers) using a non-BB turbo. remember the bigger the turbo the longer it will need to spool up. honistly i dont see the need to buy a BB turbo unless u have a turbo the size of a basketball. a t3/t4 or even a t4 wull spool up around 3k-4k rpm maybe even a little sooner
ask kevin716 how much faster my BB gt28r spools than his saab t3.
no one beleives me when i say my shit starts to hiss right off the clutch. ask the regular mighty crew…they didnt beleive me until i left the one day. i make a full 10 psi by 2500rpms EASY
at least up with my cubic" range, not too many people use BB turbos. the 300rpms faster they spool isnt worth the money. remember, with our bigger cubes comes much bigger turbos.
my turbo is relavtively small for my engine (76gts .81ar on a 6L). it spools pretty fast and gives me a very nice power curve. as long as you dont get a shit wheel, and have an appropriately sized exhaust housing, you will be satisfied. the small spool difference is hardly worth the money spent.
the smaller the exhaust housing, the quicker the spool, but the less top end. this will give you a flatter power curve. the bigger the exhaust housing, the spool time is slightly longer, but it will give you more top end. the power curve on this will look more like a supercharger curve
as far as wastegates go… i dont have any experience with internal wastegates, but i would say, as long as it does its job (limits boost psi, prevents spike/overboost, etc, at the same time doesnt create an unwanted exhaust leak), then your in good shape. external wastegates are like so: you got a relatively large turbo(s) for your engine, and want to be able to run low boost, get a large® wastegate. why?, because thats more potential psi you need to releave from the turbo. visa versa, if you have a small(er) turbo, and/or you plan on running higher boost, you dont need as large of a wastegate. it gets a little complicated at first, just keep askin questions
after what i went through this weekend with my internal wastegate, i say go external. It will most likely be easier to get everything to fit nicely, especially in a custom application
good response…reliability…scalability… i know i can’t go big immediately without looking at internal buildup, tq converter, etc, so that’s not the first concern.
^ as i stated earlier…probably your best bet and best bang for buck as all the difficult work is done for you, and if you PM him he will talk to you about upgradability
Do not clip the turbo… This is what people do to an improperly sized turbo for their application…
Turbos are designed a certain way for a reason… clipping the turbo is the equivalent of fixing an exhaust leak with duct tape… yea… it will work… but, it’s retarded. A proper sized turbo should not need clipping. I never understood why people would do this… I know that it allows more airflow yadda yadda… but if you wanted more CFM you should got a bigger AR. It’s magazine engineering at its best.
For the application your looking at… you want lower end power anyways… The scions don’t rev to the sky, so I’d concentrate on area under the curve and not high end.
I’d go minimal on everything… If your staying modest, no need for the biggest and best… besides… biggest and best costs too much.
People get too caught up in getting the biggest baddest things out there… and don’t realize they could probably do a whole lot better with a whole lot less.
ie. The DSMs that run 12s on 16g’s and beat the DSMs running FP Greens / 20Gs
EDIT: Besides… it’s a whole lot more fun when you run “faster then you thought you would” with less, then when you run “not as fast as you probably should be” with more.
yep, i know about dezod and i know he knows his stuff. but before just going with a kit i wanted to understand some of the mechanics of a unit…as well as the pros/cons of things like water cooling, ball bearing, internal/external wastegate, clipping and probably more things that i am not yet aware of. i also don’t mind the ‘difficult work.’
i could certainly just a size a kit solution to my budget…but i would rather get a solid education in the process. i was in the perf shop the other day and a typical question i heard from others was ‘how much will it cost to install, and how much hp will i make?’…sure, those are 2 important questions, but if that’s all you ask then you deserve what you get…or people who just buy something based on a brochure…whatever.
i guess my first start is i will check the flow maps of the kits currently selling to see where they plot on the graph. although i have to believe that theory vs real application has to change things…like heat, length of tubing and pressure will change air density (i’m a scuba diver so i am just applying what i know about pressurized air). i figure it isn’t as textbook as saying i can push x amount of air through a straw…because if i am under pressure or at a different temperature i can actually push more or less through the straw. i didn’t see where temp entered the equation in the map formula, but maybe it doesn’t?
but that is my point…i would like to actually understand what i am doing so i can make the right decision, not just base it on a cookie cutter kit that some other company thought would be great from a marketing standpoint (which may turn out to be great regardless). plus i may want to modify that kit to suit my needs and i’d like to know what those changes will mean.
i started with another book, supercharging,turbocharging by earl davis…some meat in the book but alot of it was just advertisment for fi companies. focus, the links you posted were very helpful, and i will get the other book you mentioned. ninja, i hear what you are saying about the clipping. makes sense. keep the feedback coming.
forced induction tuning is another good book. another note on bb turbos though, spooling fast is not always all good, the faster spool means a faster increase in power, which mean you have a better chance of loosing traction. with a non bb turbo the power curve is moer gradual. plus, bb turbos are more expensive and very expensive to rebuild. as far as i know if the bearing in your bb turbo go you have to replace the entire center section which will cost almost as much as a new turbo. not saying that the turbo will go bad on you but you never know.
also, make sure to run an oil restrictor with any turbo you run