ive searched all around to find some 220+ greddy 15g setups. ive seen a few 200+whp and a couple 220whp 15g setups but not that many. is this due to the crappy internal wastegate not holding boost and the very restricted downpipe and manifold? or is it becasue this turbo is just too small. i used to run this kit but made 190/191@ 13psi with the stock downpipe and 2.5inch exhaust...boost would not hold at all.

i have a ccFab log manifold and a go-autoworks 2.5inch downpipe (its the only one has made). im going to have the 15g rebuilt and have the internal flapper welded shut so i can run an external wastegate. i was even thinking of having the 15g insides upgraded to the 19t, but for the money, im not sure its worth it.

id like to see around 250whp @ 15psi or as low as it can be but im affraid even with a bigger dp, better manifold, and external wg, id be pushing this turbo to hard and my iat's will be sky high. id hate to spend all the money on the rebuild (and possibly upgrade) to be very disappointed or to damage the turbo from over working it.

btw, this would be done on a vitara/fjt custom i-beam setup.

 

I had one of about 3 cars (that i know of) that maxed out the 15g... 252whp on a dynojet. I used a manual boost controller AND a timing belt tensioner spring safety wired to hold the wastegate arm shut. It spiked out about 17psi, then fell to 15psi at redline. This was on a stock block y8.

If you are going to get the 15g worked on you should go ahead and get the 19t wheel put in.... the 19t has been pushed to 300whp. I talked to a company a few years back, they said it was about 300? w/ rebuild to get the wheel put in... i'll try and find them.

The only reason I didn't do the 19t was because i got a free holset h1c.

 

can u find the place that can do it for that price? gpopshop quoted me like 375 for the rebuild plus 175 for the 19t wheel and machine work. all in all, its about 600 bucks for a brand new 19t.
ive seen the thread with the 19t making 300whp, but how hard was the turbo working? im afraid of spending that much money on a turbo and kill it by pushing it that hard. ive also seen someone do the 19t upgrade and only make 230whp. my buddy has a 19t with a tubular elbow and 3inch dp and exhaust and he put down like 230 with a spring mod too.

im just wondering if the log manifold and external wastegate would help me get there and let the turbo not work as hard. like i said, i want to keep IATs down as well.

 

the price i quoted was probably off... like i said it was a few years ago.

these guys....
http://www.blouchturbo.com/upgrades/

19t video:
http://www.blouchturbo.com/clips/upgrading101/index.htm

The 19t would be pushing hot air at 300whp, but wont at 250whp.
The 15g would be pushing hot air at 250whp but wont at 200whp.
If you want 300, just get a gt28rs and call it a day.

 

thanks alot!
what do you think of the 18g on a SOHC? i just found a minty 18g with a 2.5-3inch downpipe. with that, seems i can hit my goals easier but im affraid that it might be too laggy.

 

i am in the same boat. i keep going back and forth as to what money is worth spending on what turbo.

 

The 18g was my "dream" turbo back in the day lol... I had the chance, and really was the first to experiment with installing one, but never had it running. JFK had it on his car or a buddy's car?, maybe he could chime in. Not sure about your manifold placement, but with the greddy sohc manifold you have to space it out at the head w/ a extra head flange. If not, you have to grind the **** out of the block, and you still could not run a filter, so the extra flange was the way to go. The 18g would spool nicely IMO.

 

i had on t25/t28 on my sohc y7 and it was on 13 psi with arphead studs pulls hard from 0-80 then just died off i would invest in like at 50 trim turbo with like a .48ar exhuast or just a straight t3 turbo would be best for spool time..plus with those turbo you will make bigger number with less psi

 

when you say nicely, what do you mean? lol. i think JFK said he had like 12psi by 3500 and like 20 at 4200. im used to that full 13psi at 3500 with the 15g...lol. i just dont want a 2k powerband since this is a full street car, with a/c and p/s.

 

? I know it would spool faster than my old holset or my current 60 trim. I liked the way the bigger ones spooled, so for me it would be nice. Full boost at ~4000 sounds good to me.

 

would you happen to know what the 18g would compare to?

 

Im not too sure you could use the 18g and still keep a/c on a sohc???
The 19t may be your best bet, especially if you don't plan on going over 250

hope this helps you find your answers...

how to figure spool, hp, boost for each turbo based on the cfm calculator...
http://www.lovehorsepower.com/MR2_Do..._flow_maps.htm

cfm calculator for your engine....
http://www.lovehorsepower.com/CFM1.htm

15g, 19t, 18g maps....
http://www.stealth316.com/2-3s-compflowmaps.htm

 

Looking at a 18g from a DSM point of view, it spools in the 3300-3500rpm area in the 7cm2 turbine housing.
The TD05-18G is a 40lb/min turbo.
Its slightly a bigger turbo than the stock Big16g from an Evo.(35lbs/min)
They are killer street turbos