EVO VIII twin scroll turbo...let's discuss!
 

greetings all,

i just completed my 1.6l diy turbo build. all is well, the car is a blast to drive. Thanks to the many board members who helped answer my various questions. I still consider myself a "green" mechanic, so I appreciate the helpful tips from everyone.

At any rate, I am going to start gather new parts to turbo a BP. I am considering turbo options, and I'm quite interested in the evo 8 unit. I like the fact that its a twin scroll unit, and I have a friend who does the most most amazing fabrication work ( works for ams), so a manifold is no problem.

my questions are:

1) how good of a match is the evo unit for the 1.8L.?. I am still having a hard time reading compressor maps, so an expert may be in order to answer this. I'd like to hear opinions on what spool might be like, also.

2) since im a college kid, I am doing the build on the cheap. should I have any problems running something like 8psi on the evo unit (using fuel bandaids) or should I go for a more conventional small turbo approach ( thinking 14b)

thanks,

-dan

how about a link?

I dont know what ams is.

AMS is a serious shop out of Chicago. They are mostly a Evo shop but also have one of the worlds fastest ka-t 240sx's. They make great stuff.

I'm surprised you haven't heard of them, they have some of the fastest time attack cars in the US.

http://www.amsperformance.com/main.php

never heard of ams!! for god's sake man, youre from chicago too!

http://www.amsperformance.com/ ....watch the vids and you'll freak.

in other breaking news, the germans surrendered, and europe is going to have to be rebuilt. jk

damn looks like someone beat me to it

Not to beat on poor Loki, but +1!!!

Back to the question at hand, the evo 8 turbo is pretty good. It might be a little big for a 1.6 but the 1.8 should be able to spool it ok. They're built to flow 20+ psi so you really wouldn't be fully utilizing it at that low of boost.

Alright thats a good line. I didn't know where the fuck you were from. Theres AMS's all over the fucking place.

And awesome that chicago is starting to get some cool turbo guys.

and DB the link was for compressor maps. or turbo specs

The evo turbo isn't overly different from the normal 16g's.

There's a lot of upgrades out there for them too. TME/20g/etc.. Of course, by the time you get into that kinda stuff, you could have gone for a GTK turbo or something else, price wise.

Heh, I was over at AMS for their new shop grand opening bbq. The new shop space is so damn nice.

The 16g is a pretty nice oem turbo, with a properly designed split manifold to take full advantage of the twinscroll it will definitly spool faster than a similar big 16g.

Dirty, update your location profile ;)

dont know much about the particular turbo but twin scrolls have been around for decades (factory on the early 90s turbo 4wd celicas). chances are you wont see/notice a difference over the same turbo with a single entry housing. perhaps if you designed the manifold like the factory did (however that is) you could realize the couple hundred RPM spool improvement but that would be it.

I Guess they keep the pulses from opposite ports away from each other to avoid the whole FM/BEGi "directed pulse" argument.

DB, clear your PMs, i've been trying to reply to yor PM all day, lol

as far as your build, sorry im no help, i still dont understand turbo maps either, but i assume you are considering the evo VIII turbo because you can getone for cheap/free from your frineds shop, if so go for it

i read a post by quirt crawford, of crawford performance, regarding the spool characteristics of equal length and non equal length manifolds. On the non twin scroll manifold, the powerband came on 750 rpm later than the twin scroll mani.

granted, this test was on a Subaru Legacy , but Im sure the same theory would hold true on a miata.

also, does anybody know if the all trac turbo is a version of the ct 26?
-dan

Of course on a subaru, with the exhaust ports on the bottom, there's a lot of ways to improve spool

care to elaborate

Well, consider this.. on the miata, with a log manifold, you've got about a foot of pipe from the exhaust port to the turbo. On a subaru, from #1 to the turbo (in stock location), it's like 6 feet, maybe more...

The exhaust ports are down by the lower control arms, the turbo is up by the passenger side firewall.

sorry OP but we're threadjacking a little biti used to own a bugeye wag fwiw

i understand what your saying, but i think your comparing apples to oranges. The size of equal length vs. unequal length headers in subaru's are almost the same. Plus, tons of dudes make 500 plus hp on stock headers ( im talking about usdm ej25s)...the real benefit of the eq length headers is the spool.

like i said, im a green mechanic so there is probably a flaw in my arguemnt. experts chime ..now

-dan
ps your avatar is hilarious

i know i know! the early alltracs used the single entry CT26. the 91-93 used the twin entry ct26. the 94 and newer GT-Four (same car, not imported to US) used the CT20B with the ceramic turbine (unofficial designation I guess?).


I have a cracked ct26 turbine housing in my garage. nice paperweight.

The evo turbo is a good option but, unless you are gonna run alot of boost a normal 16g will fit the bill for you. I have been considering steping up to one myself. fWIW a 16g when done right can get you to 300 hp so IDK how much farther you wanna go from there.