Death trap

I'm trying to find out what size BOV and Wastegate I should pick up. I have a stock 5.3l LM7 and a Master Power T70 turbo. Plan on running 8-12 lbs boost (think 8 will be plenty for me). I haven't been able to find consistent info on what size bov/wastegate (seen anywhere from 38-50mm). Any help nailing it down would help, Thanks!

Also, Im putting this together on a budget and am new to turbos, what brands of BOVs and Wastegates should I be looking at? I don't think I can swing NEW Tial or other high end stuff but if I could get a used one would that be better then new stuff about the same price? again any help is greatly appreciated!

Death trap

Anyone? Only info I can find about sizing wastegate/bov that isn't an example of what someone is running is basicaly, large turbo + low boost = large valves, large turbo + hight boost = smaller wastegate (I'm assuming that you would still need a decent size BOV) and info like that. none explain with numbers, large and small are veag terms Also is there any disadvantage to running a BOV or wastegate that is on the bigger side??? Or can they ever be too big???

LS1NOVA

iTrader: (12)

I would run a JGS 40mm from Brian Tooley Racing and a 50mm China bov from Race Parts Solutions.

Death trap

Thanks! I really appreciate the advice! If you don't mind me asking, is there a math formula or something that is used to come up with those sizes? Or are they from seeing other builds and or personal experience? I'm trying to learn as much as I can about turbo cars and even tho knowing what to use on this build will get me threw it, I still would like to learn how to size it for other apps. Thanks again for the advice LS1NOVA!

ls1_chevelle

iTrader: (9)

Nope, Just a proven combo... Id say up to a 76mm(mid frame) a 40mm wastegate with good priority will work fine and give a guy the boost control you will need. A large frame 76mm to 88mm Id look at a 50-60mm wastegate. From there you are looking at dual 50-60mm for twin 88s and bigger.

BOV, you want it to relieve essentially as much as possible to prevent compressor surge. 50mm is pretty standard these days.

There are flow data calculations to size turbos or you can call a reputable turbo sponsor and tell them your combo, they will size it accordingly.

Sarg

iTrader: (6)

I went with two eBay emusa 38s and less than a year I am starting to see rust on the valve face. They still function, but this is not confidance inspiring. I worry now about them sticking and over boosting. Should have gone tial or jgs, but I was trying to save a buck, lol.

ls1_chevelle

iTrader: (9)

Yup China will do it every time to ya! Save a buck now so you can spend another chunk of money later haha.

Sarg

iTrader: (6)

Oh I have a bunch of other little parts that are Chinese like my intercooler that are working great. Just would probably avoid it on the wastegate next time. Good part is I am only out $100 vs the $500 I would have had in tial units.

ls1_chevelle

iTrader: (9)

Yea you guys are lucky(atleast I think), our season is pretty small up here and the last thing I want is knock off part holding me back.

Ive had lots of luck with the china intercoolers too, just one of those things. Having a wastegate stick shut and melt a motor down wouldn't be on my priority list hah.

Death trap

Thanks guys for the replys, it's very much appreciated! All of this info is helping clear up alot of the confusion. As much as I'm trying to keep a build on a budget (it's supper easy to get carried away LoL), but I don't want to risk every thing just to save a few bucks. Some times it's just a better investment that way. As I was kind of assuming, I will avoid knock off bov and wastegates and try and get some quality parts. Thanks again guys

Sarg

iTrader: (6)

Oh I don't know, have known a ton of people using knock off BOV's and never heard of issues other than finding a replacement flange. I mean there are people out there that actually advocate not using a BOV at all. I know that Cosworth was not running one at all. Not sure if that is still true, but worst case your $40 BOV fails and you hear some funny noises from the turbo for a bit. You could honestly buy 3-4 ebay wastegates for the price of one new Tial. That being said, I got a used Tial 50mm for $75 online

Sarg

iTrader: (6)

Nah, the local track opens later than a lot of places up north and closes earlier a lot of times. There are others further south that open early, but right now I don't have a trailer, so I am left driving to the track. I would much rather drive my junk 30 miles than 2-3 hours through Atlanta traffic!

But yeah, my frozen boost A2W intercooler has been a champ and seems pretty well made thus far. Several freinds rocking various ebay BOV's, a number using intercooler piping kits, I use a bunch of t-bolt clamps and silicone parts from ebay.

V-band clamps are another thing not to cheap out on. Dealing with that now too....hmm seems anything exhaust related except maybe a muffler may be better to get made in USA as it has to deal with some punishment in a turbo car. I know for a FACT that flex joints better be well made or they are going to have a high speed come apart through your turbo! Have not had it happen to me, but have seen the after effects first hand!

Death trap

Thought I read some were that some say running without a bov is thought to possibly do damage to turbos???? Idk I'm planing on running one for sure, there defiantly cheaper then replacing a turbo LoL

Death trap

Man I live 5 mins from one of the busiest tracks in the USA. I don't remember when there opening day was but they are scheduled to be open till mid December i think! Weather permitting they are open at least 4 days a week not including private track rentals. Killing me not having something together worth running

Sarg

iTrader: (6)

Yeah it can cause compressor surge which basically stalls the wheel while exhaust gas is still pushing on it. I run one, but what I am saying is that worst case if it goes out it will not be instant death to the motor like if a wastegate freezes up and causes and overboost condition.

Death trap

Ahhhh I see, so a BOV fails it's not the end of the world but the wastegate is another story. Thanks Sarg

Grayguy

Is anyone using the on3 wastegates?