Two tial 38mm wastegates better than 1 60mmwastega

snowballs4, Feb 16, 6:14pm
any help would be good
bigfatmat1, Feb 16, 6:18pm
mathematically speaking two 38mm has less surface area than 1 60mm thats my input. you work out the rest.
tmenz, Feb 16, 6:19pm
1 x 60mm pipe has a bigger area than 2 x 38mm pipes. 2827mm² as opposed to 2268mm². 25% bigger.
jsbike, Feb 16, 6:20pm
whats wrong with one 38mm!
elenor, Feb 17, 5:33am
you will not get a boost loss with two
snowballs4, Feb 17, 9:30am
putting a masterpower t70 on with one wastegate that small isnt good, The turbo is rated up to 900 hp, to much pressure for a little 38mm
snowballs4, Feb 17, 9:32am
So what you are saying i have to go to a 60mm steam pipe manifold to run a 60mm wastegate correct! as i have a 42mm steam pipe one, would it be better to use two 38mm wastegates!
jsbike, Feb 17, 9:37am
pressure isnt the problem, the tiniest wastegates take pressure fine, same as big wategates. The thing you need to work out is, whats the LOWEST boost you will be running. A smaller wastegate will run high boost on a big turbo fine, its when you have a big turbo and you need to run low boost that you need a big wategate.
1ollie, Feb 17, 11:43am
This question cant be genralised at all thats how things get broken and blown up!
What engine, what turbo, what manifold, what boost pressure and power are you trying to achive will give you your answer!
By the sounds its some sort of RB! unless your aiming for over 500kw then you will find that 1 of the new Tial 44mm MVR's will be more than enough(if you have a well designed collector/wastegate feed area on your manifold)
snowballs4, Feb 20, 2:34pm
so why is every one going to the tial 44mm ones! we are aiming for 500kw, hence why the big parts, what i dont understand whywhat is the real difference between a 38mm compared to a 44mm, i thought it was to hold pressure!
bigfatmat1, Feb 20, 3:35pm
big turbo/low boost = bigger wastegate
big turbo/high boost = smaller wastegate
small turbo/low boost = bigger wastegate
small turbo/high boost = smaller wastegate

wastegates diverts exhaust gasses in order to lower boost. so bigger the hole the more it can divert
1ollie, Feb 20, 8:12pm
Because they are an awesome wastegate that flow very well. The difference is the 44mm flows much more than the 38mm and there is a bit of math involved.
And 500kw! thats alot of power and once again I say it comes down to the whole package of what engine, what turbo, what manifold, what boost pressure and power are you trying to achive!
If you are realisticly(and ifyou actualy have a complete package that can make it) going for over 500kw then I would advise something along the lines Tial V60 or Turbosmart Progate50 but bearing in mind they are both around $1000
snowballs4, Feb 20, 11:31pm
rb30det 42mm steam pipe steel manifold with a masterpower t70, 90mm throttle body, 1000cc injectors forged pistons etc.
jsbike, Feb 21, 7:56am
@ $299, its a waste of time and likely to be shit quality. How much do you value your engine! When it comes to wastegates your best to stay with quality, GENUINE Tial or any of the well known brands.
snowballs4, Feb 21, 11:40am
yeah fair call
snowballs4, Feb 21, 4:56pm
as you say bigfatmat1 wrote:

big turbo/low boost = bigger wastegate
big turbo/high boost = smaller wastegate
small turbo/low boost = bigger wastegate
small turbo/high boost = smaller wastegate

38 mm will be suitable for 19-20 psi!
1ollie, Feb 21, 6:22pm
I advise you stick to Tial or Turbosmart as they are 2 very good brands if not the best, have good pricing and have good after sales support & parts availability.
Well with that above quote I think you will find that thats a pretty generalised set of 'rules' and I highly dout a 38mm will be even nearly enough to control your boost
jsbike, Feb 21, 7:34pm
I think a 38mm would be a BARE minimimum even if running highish boost. What internals have you done! 500hp on a standard bottom end is starting to push the envelope a bit. I'm aiming for 400hp @ 14.5psi on a rb25det neo with mine. My turbo setup which was on an rb20det orig was able to run as low as 10psi without spiking with only 32mm wastegate (32mm inlet/35mm outlet). Not sure yet if it will spike @ 10psi on the 25det as im not running yet. your better to get a wastegate thats too big rather than too small
snowballs4, Feb 21, 7:44pm
acl race bearings forged conrods and pistons, its been a very long project, i heard about these wastegates being good aswell Synapse
I used to have a 25det but it snaped a conrod, Loads of fun!
1ollie, Feb 21, 9:29pm
If a 38mm controls boost properly on a 3L DOHC inline 6 with a MP T70 on 19psi I will be fricking amazed! I myself would not waste my time trying it!
I mean its one of the most important things that keeps your motor alive and skimping by about $400 on a $10000++ set up makes no sence
1ollie, Feb 21, 9:31pm
I would stay away from Synapse as a few people running electronic boost control are having problems and they are only new in the country and for nearly the same price you can get a proven product with years of development in it!
snowballs4, May 15, 4:42am
yeah very good point, thanks for your help