Wastegate size calculator

[GriZZly]

Im wondering if anyone has ever come across an online calculator or program that calcs the size a wastegate needs to be in order to sufficiently bleed off excess boost from a certain capacity engine?

Wastegates dont come with minimum or maximum power levels for obvious reasons but is there a way to calc what size wastegate is to small and whats optimum? as the bigger wastegate you get the more you spend..

[MZ20]

I often wondered the same thing - i generally go with the size over what everyone else is running that is my calc!

Glen

[The Real Roadrunner]

how much airflow, what turbo/engine combo?

no real calc afaik but its not to hard to work out.

on a customers 780+rwhp 2L engine we were using a 35mm gate to keep it from pushing the gate open at high boost (ex mani pressure was higher than boost due to the small housing needed to make it spool in a time that was still on the calender)

cheers
linden

[GriZZly]

I hadnt thought about that but i dont think it would be an issue in my case.. i was thinking more along the lines of, if im running 15psi through a gt42 on a stock 1uz engine @6000rpm will the exhaust gas flow overcome the flow capabilities of a 38mm gate and start increasing the boost pressure? probably! but what about 44 and 50?

a 50mm is almost twice the size of a 38 so im sure that would be fine, but they also cost approx. twice as much as a 38mm gate..

so this brings me back to the original question is there a way to calculate it?

[Ben Wilson]

You could probably calculate a number, but it would be very hard to come up with something relevant. There are just too many variables. The wastagate plumbing alone could make up to a 20%* difference in flow.

* - Just a guess, some of the bad ones I've seen could be worse than that..

[chris davey]

I was thinking the same. A 50mm wastegate plumbed say 120deg away from the direction of natural flow "may" flow less than a 35mm plumbed in a way that is very efficient ie. into the turbine housing.

I think there are just too many variables to use a calculator so it may just be a case of see what others are using and how they are finding them.

[millsi]

lol, are you reading my mind?
i will be running a tsmart 45 pro gate. hoping to make 350rwkw at 15psi on my stock 1uz

I hadnt thought about that but i dont think it would be an issue in my case.. i was thinking more along the lines of, if im running 15psi through a gt42 on a stock 1uz engine @6000rpm will the exhaust gas flow overcome the flow capabilities of a 38mm gate and start increasing the boost pressure? probably! but what about 44 and 50?

a 50mm is almost twice the size of a 38 so im sure that would be fine, but they also cost approx. twice as much as a 38mm gate..

so this brings me back to the original question is there a way to calculate it?

[GriZZly]

Hey millsi i seriously hope my conversion isnt as difficult as yours.. Actually planning on running a GTK1000 but the GT42 is the closest and better known by most people so i just quoted that..

I just read through your build up thread.. so the plan is to start on the turbo stuff upon your return? Im probably working on a similar timeframe.. would like to start jan/febish with the plan to finish by end of autumn

as far as the wastegate goes im pretty much settled on a 44mm tial as i doubt the 38mm will cope unless i ran another 10psi of boost or something..

Just out of interest can you tell me the internal dimensions of your engine bay? so ive got an idea what im up against and compare those dimensions with mine?

Cheers

[millsi]

heya grizz, yeah hoping to get its mostly done by the end of next year, still need to buy my tko600, an intercooler, 7mgte injectors and upgrade the brakes lol.
sorry im overseas till apr next year so cant measure for you, theres a few other blokes on here with the same year model who might be able to help though.

[GriZZly]

yeh im considering the tko as well but if possible would rather go for a T56.. should handle the ~350rwkw im aiming for and will give a nice low rpm cruise

Didnt really put 2 and 2 together there did i.. overseas, car here etc

I got 2 sets of Gen1 3sgte injectors theyre also top feed 440cc.. means u dont end up with spares.. and they do fit afaik..

cheers

[millsi]

cheers on the injectors, will try and confirm they fit.
getting noff topic now but the tko600 has 0.64 fifth as opposed to the t56 0.62 sixth. so bugger all difference really. plus the tko is stronger