Well, I've been doing a lot of research about turbo sizing, and it looks like the Disco Potato turbo (Garrett GT-28RS) of SR20 fame is a really good match for our engines. Now sure, when you plot our engines on several compressor maps, both the 16G and t3/t4 hybrids are good matches too, but there is something to be said for 20 year old turbocharger design aerodynamics...

So I was wondering if any of you are/were considering this turbo, or if there are any 420a's running it already?

I was originally considering the tried and true hahn super 20g setup, but the thought of replacing my clutch every year, and axles twice a year, and at the same time waiting until 3700+ rpm for my powerband to start, kind of made me reconsider. Now, the idea of a completely useable powerband and a setup that still puts down 300+ hp, with throttle response like that of an N/A car, really appeals to me...

I'm aiming here to start a good thread about using alternative turbochargers (read: more modern..) as opposed to the old warriors (16/20g, t3/t4 hybrids, etc..). After all, the advantage our engines have over the 4g63, is that they are of a much more modern design, so why then do we continue to bolt turbos onto them that are over 15 years old in design? Anyway, something to think about..

By the way, I've been lurking on this forum for a while, this is probably my first useful post. ;)

Dan

Modern or not, the 16g can do it job, and that is to make speed. I can run my
car under 2500 rpms, and here the turbine spool and as I hit 2500, then I am boosting.

As far as the potato turbo thingy, you sill need to get a manifold made to fit the turbo that you need and that's probably a big reason people stick with the tried and proven technology of the 16g, the new 20g, and the hybrid t3 and t3/t4 turbos.

I have to admit though that though I've heard of the potato turbo, I have no clue as to what seperates that turbo others. Is it ballbearing?

-------jezreel
hrc stage 1, sfmu, ml, prokits, egt, boost gauge, apexi tt, costum dp, dynotune fp gauge. gst muff, turbo spoiler

nothing like driving with the windows down and the music low: i love hearing the turbo spool, swwwhhhttt!!!!
thanks for www.kaptainmyke.com for the sig hosting :thumbsup

the potato turbo would work great on out cars, exspecially for scca comp. spools really quick and reliable, but i doubt the 420a will make alot of pozwer with that turbo. 300whp seems kinda farfetched with the potato turbo on a 2.0, but i dunno i dont know anyone that runs one

but anywho if u decide to go bigger i gotta fresh 20g ill sell ya, think im moving to a 25g

DWAYNE H
1996 eclipse
under construction widebody eclipse, targa top, 19inch rollers, big brakes, 10 point custom cage, frank 2.4 hrc s20g turbo, custom marble paint job

2000 Yamaha R-1, 165rwhp 117 ftlbs tq

ALMOST THERE...... MUWHAHAHAHAHAHA

i for one am curious as to what the hell a "potato turbo" is?

Good question, because the base dynamics involved between the sr20 and 420a are so similar on the exhaust side,(thermal exhaust gas velocities, volume, and ovelap frequencies from cylinders firing) that turbo would be a good consideration if your looking for fairly quick punch. Although I think things would taper off more drastically with our motors when you get higher in the revs.


boosted 420a and ej2o..(my 2liter v8 eaters)

Disco Potato = Garret GT28RS Ballbearing Turbo

Old "T" Turbo: T3/T4E - .63 A/R Turbine Housing
New "GT" Turbo: GT28RS - ATP GT30 T3 Style drop-in - .82 A/R turbine housing




http://www.atpturbo.com

As I understand it, the disco potato was a pet project of some engineer and turned out to have extremely good characteristics for 1.8 to 2.0 4-cyl applications so Garret added it to their official lineup. Supposedly spools quickly like a T25 but has the topend power to keep pulling. Definitely a good choice for autocrossing, not so useful for drag racing.

In my opinion, a "somewhat laggy" T3 or S16G is better suited for our application because we are FWD and therefore very traction limited. Aren't the SR20DET silvia's RWD?

QUOTE: Definitely a good choice for autocrossing, not so useful for drag racing. In my opinion, a "somewhat laggy" T3 or S16G is better suited for our application because we are FWD and therefore very traction limited. Aren't the SR20DET silvia's RWD?

----------------------------------------------------------------------

The 240/silvia's are rwd and would make better use as you've stated, but that turbo originated from an sr20de in a Sentra SE-R and the disco part was dubbed from the flip flop paint scheme of the car. Think SCC magazine, you guys may remeber the issue. Traction was an issue when launching under testing because of quick spool.


boosted 420a and ej2o..(my 2liter v8 eaters)

Well if you plot our engine on the above compressor map, using 2.33 psi and 32.44 lb/min, you'll see that it ends up being a good match. This is assuming 18 psi of boost at sea level, with a 7000 rpm redline, and a 1.5 psi drop across the intercooler. Now obviously if you have a 2.2L or some stratospheric redline, then this turbo probably would not be a good match. But on a true street car that's daily driven with a near stock redline, it seems this turbo would make the car feel like a v8.

Now about this using a larger, slower turbo to avoid traction conditions.. Hahn runs a S20G and they still have to stage their boost levels to get rolling with slicks and using a sohc neon transmission. My point being, if they still have to stage their boost levels with a 20G, then you would most definitely have to stage them with a 16G, and thus with something like the potato. So if you're staging levels regardless of which turbo you're using, the point is kind of moot.

Oh the flip side though, the stock 420a doesn't really start to come on until after 3000 rpm, so it seems that any improvement on that would be great, whether it's through a 16g, or otherwise. I guess I don't know what i'm bitching about. ;) Just trying to make conversation I guess...

Dan

i see what ur saying in regards to traction problems, ive thought that out to, with the amount of torque the 2.4 lays down, i will have problems with the 20g coming on to early. but

i started researching the best boost controllers money could by. my find and choice is the apexi avcr. this is one of the best boost controllers money can by, you have boost gear selections, were u can program boost to your gear selection. u can even program boost different boost levels by 500rpm increments and set spike boost pressure at a cetain gear.... say third, when our tranny really murder the competition. jus somethin to think about while choosing which turbo is right for your applicaiton

DWAYNE H
1996 eclipse
under construction widebody eclipse, targa top, 19inch rollers, big brakes, 10 point custom cage, frank 2.4 hrc s20g turbo, custom marble paint job

2000 Yamaha R-1, 165rwhp 117 ftlbs tq

ALMOST THERE...... MUWHAHAHAHAHAHA