Savington

iTrader: (31)

Why is this? I ran a .48/.49 T25, and while the larger SR20 T25 is nicer for more power, you can easily hit 150-200rwhp with a DSM T25 and WI, and have insane spool to boot. I was seeing 13psi at 3000rpm.

juhanis

i run a 14b on my car... and it spools like a switch. FAST spool. when you see the turbo and compare it to the other things they run on miata's you're going to be disappointed by its size. its a great little turbo for the miata. i came from a small 16g, and if you compared the two, the small 16g is way bigger. if i wasnt using 225 proxes t1r's it would spin the tires in 2nd from a roll just from how vicious the spool is. plus they're cheap and easy to find. all the more reason to buy one. if you're happy with 250hp or less this turbo isnt a bad choice.

marty_uiuc

iTrader: (1)

you're right! :gay:

i just checked again. from smallest -> largest...

compressor wheels, 14b -> small 16g -> big 16g = super 16g -> evo3 16g
exhaust housings go 14b -> small 16g = big 16g = evo3 16g -> super 16g

mazda/nissan

iTrader: (2)

thats the way to buck up and confess, if only the rest of the forum were this way

jwarriner

There is no Super 16G compressor wheel.

magnamx-5

iTrader: (7)

Uh bud i think you are confusing absolute choke flow with useable flow the order for sub 15 psi should be
14b, big 16g, small 16g, evo 3 Other than that your idea is the same one i set out with initialy. And look at me now 18 psi on WI only. +1 on getting the megan stuff and running bracing.

marty_uiuc

iTrader: (1)

which is why it says big 16g = super 16g

jwarriner

Don't forget the 18G which falls either between the Big 16G and Evo 3 16G or above the Evo 3 16G depending on who you ask. And then of course there is the 20G wheel which is worth about 30-50hp more than the Evo 3 16G and 18G.

Savington

iTrader: (31)

I am rather sure the 18G is larger than an Evo3 16G. I'll ask my buddy who had both on his WRX at different times.

A 20G would be WORTHLESS on our motors. I have another friend running a 20G on a built 2.5 liter STI block, and he doesn't spool that turbo until after 4,000rpm. It ******* MOVES once it's spooled, but jesus it takes forever.

Edit: Asked my friend. The 18G is definitely larger than the Evo3 16G.

jwarriner

Compressor Wheel Inducer, Exducer (in inches)
14B 1.695, 2.285
16G 1.830, 2.365
B16G 1.893, 2.680
E16G 1.905, 2.680
18G 1.986, 2.680
20G 2.070, 2.680

Yes, the 18G is a physically larger wheel by .081" on the inducer but what you are not seeing is that the Evo3 16G has a smaller hub than all of the above so the the blades are larger. The Evo3 16G is .660" from the leading edge of the inducer to the shank, same as a 20G, the 18G is .620" on the same dimension. The 18G is rated at 42lb/min. The rating of the Evo 3 16G is in dispute. I've seen 39lb/min from a reputable source but out in the wild they seem to be making more power than should be possible with 39lb/min. I've also heard 42lb/min. I'd guess the Evo3 16G is probably on par with the 18G with the advantage going to the 18G by a very minute margin at high boost (think above 25psi). In the useable range for a Miata the Evo3 16G may have the advantage, especially because it's a shitload lighter, it's lighter than a small 16G wheel (that hub thing, along with thinner blades).

As for the 20G being useless on the Miata... I disagree. It's simply a larger turbo. Is it useless on a stock 1.6L with band-aids at 10psi? Probably.

My 20G spooled to 15psi by 3800rpms on a 2.0L, this was with clipped TD05H turbine wheel and ported 7cm housing.

You can argue with me all you want on MHI turbos but you will be wrong. I have hands on experience with every single one of the above turbos and I have specs on everything.

marty_uiuc

iTrader: (1)

i have heard that for a given displacement and turbo, boxers cannot spool the turbo as quickly as an inline motor. however, i don't know how much truth there is to that...

jwarriner

I am not sure on that either. But I am assuming, by his wording, that he meant the onset of boost wasn't until 4000rpms, which is pretty laggy. A 20G is not that big a turbo.

Miata-MS

Never heard that before, but it kind of makes sense as the exhaust runners have to be longer on a boxer motor than a regular inline-4. If not for that reason, i have no idea why that would be true. Interesting thought though...

Savington

iTrader: (31)

Nono. It didn't start making serious boost until 4000+rpm. I'm not sure where boost onset was. My GT2554R produces boost under 2000rpm; doesn't mean it's spooled down there. It doesn't really get up and kick hard until a bit past 3k.

magnamx-5

iTrader: (7)

I don't think we would be good on the surge line of a 20g or a 18g with a big built motor a 18g would work just fine i think on high boost but i still defend the small16g and the evo3 to be the best turbos for our apps.

jwarriner

Evo 3 all the way.

1drum

iTrader: (1)

Will I have problems with a DIY setup here in CA?

92gsxBALTIMORE

Hey guys, first post here...

Im curious about turbo pattern on the Greddy turbo kit. I'm assuming it is a Garret t3/t4 pattern and not DSM. (edit: I found it, it is Garret)
If you are going to be choosing a DSM turbo for your turbo kit I would deff pick a 16g over the 14b. Spoolup wont be that much worst and you can flow more cfm at lower boost. And if you want to get crazy, the early Evo 16gs will spool better than a standard 20g and produce about the same power levels. Just remember that all 16gs are not created equal. And make sure you are buying a MHI 16g if you decide to get one. There are many knock offs all over the net nowadays that have inferior bearings and machining.