Here is a chart that list out most of the current turbos, and how much cfm they flow. Russ Turbo Type Approx flow @ pressure Stock Turbo 360 CFM at 14.7 PSI IHI VF 25 370 CFM at 14.7 PSI <--- estimated IHI VF 26 390 CFM at 14.7 PSI <--- estimated T3 60 trim 400 CFM at 14.7 PSI IHI VF 27 400 CFM at 14.7 PSI <--- estimated IHI VF 24/28/29 410 CFM at 14.7 PSI <--- estimated ========= 422 CFM max flow for a 2 Liter at .85 VE pressure ratio 2.0 (14.7 PSI) 7000 RPM ======= IHI VF 23 423 CFM at 14.7 PSI FP STOCK HYBRID 430 CFM at 14.7 PSI <--- derived from HP potential listed on web IHI VF-30 435 CFM at 14.7 PSI <--- estimated SR 30 435 CFM at 14.7 PSI IHI VF-22 440 CFM at 14.7 PSI <--- refigured T04E 40 trim 460 CFM at 14.7 PSI ========= 464 CFM max flow for a 2.2 Liter at .85 VE pressure ratio 2.0 (14.7 PSI) 7000 rpm ======= PE1818 490 CFM at 14.7 PSI <--- estimated from max flow numbers Small 16G 505 CFM at 14.7 PSI ION Spec (stg 0) 525 CFM at 14.7 PSI <--- per vendor post 12-27-2002 ========= 526 CFM max flow for a 2.5 Liter at .85 VE pressure ratio 2.0 (14.7 PSI) 7000 RPM ======= Large 16G 550 CFM at 14.7 PSI SR 40 595 CFM at 14.7 PSI 18G 600 CFM at 14.7 PSI PE 1820 630 CFM at 14.7 PSI <--- estimated from max flow numbers 20G 650 CFM at 14.7 PSI SR 50 710 CFM at 14.7 PSI GT-30 725 CFM at 14.7 PSI 60-1 725 CFM at 14.7 PSI GT-35R 820 CFM at 14.7 PSI T72 920 CFM at 14.7 PSI <--- Note you would have to spin a 2.0 L engine at about 14,000 rpm to flow this much air. IHI VF 25 395 CFM at 18 PSI <--- estimated IHI VF 26 400 CFM at 18 PSI <--- estimated T3 60 trim 410 CFM at 20 PSI IHI VF 27 420 CFM at 18 PSI <--- estimated IHI VF 24/28/29 425 CFM at 18 PSI <--- estimated IHI VF 23 430 CFM at 18 PSI <--- estimated IHI VF-30 460 CFM at 18.0 PSI <--- estimate based on trap speeds of cars running this turbo AVO 320HP 465 CFM at 17.5 PSI T04E 40 trim 465 CFM at 22 PSI FP STOCK HYBRID 490 CFM at 18.0 PSI IHI VF-22 490 CFM at 18.0 PSI <--- refigured SR 30 490 CFM at 22 PSI Small 16G 490 CFM at 22 PSI ION Spec (stg 0) 500 CFM at 19 PSI <--- per vendor post 12-27-2002 PE1818 515 CFM at 22 PSI <--- estimated from manufactures rated max power Large 16G 520 CFM at 22 PSI <--- upgraded flow some on review of compressor map ========= 526 CFM max flow for a 2 Liter at .85 VE pressure ratio 2.5 (22 PSI) 7000 rpm ======= ========= 578 CFM max flow for a 2.2 Liter at .85 VE pressure ratio 2.5 (22 PSI) 7000 rpm ======= HKS GT2835 400 hp 580 CFM at 22 PSI MRT 400 580 CFM at 16 PSI <--- added AVO 400HP 580 CFM at 17.5 PSI MRT 450 650 CFM at 19 PSI <--- added AVO 450HP 650 CFM at 20.0 PSI SR 40 650 CFM at 22 PSI <--- added, got lost some how in editing ========= 658 CFM max flow for a 2.5 Liter at .85 VE pressure ratio 2.5 (22 PSI) 7000 rpm ======= HKS GT3037 460 hp 670 CFM at 22 PSI PE 1820 680 CFM at 22 PSI <--- estimated from manufactures rated max power 20G 695 CFM at 20.0 PSI <--- added HKS GT3040 490 hp 710 CFM at 22 PSI AVO 500HP 725 CFM at 23.0 PSI SR 50 770 CFM at 22 PSI GT-30 790 CFM at 22 PSI 60-1 800 CFM at 22 PSI HKS GT3240 570 hp 830 CFM at 22 PSI GT-35R 880 CFM at 22 PSI T72 1000 CFM at 22 PSI <--- note you would have to run a 2.0 L engine at >40 PSI boost to flow this much air Conversions used where I had control over conversion factors: 1 HP approx equals 1.45 CFM 1 CFM approx equals 0.0745 lb of air/min 0.108 Lb/min approx equals 1 hp 1 Meter cubed/sec = 35.314 CFS = 2118.867 CFM 1 KG/sec = 132 lbs/min approx equals 1771.812 CFM power coversions: 1 PS = 0.9859 HP = 75 Kgf m/sec 1.3405 HP = 1 KW <-- edited to fix stupid typo 1 HP = 746 watts <-- edited to fix stupid typo

good call on the post Russ! from my calculations to make 400hp(which hopefully will be over 300whp) i need to flow 540cfm. i need to figure out what my current A/R is on my T3/T04B and find the compressor map to see how much boost i can run. of course this would be on a new engine..... someone help me pick a turbo please, if possible one with the T3 bolt pattern and that still spools at reasonable rpm thanks! Ben

What motor/head combination do you plan on running? That will make a big difference. If you run the sti short block with a set of spec c heads, you could run the 18/20g and have tons of low end torque, and still have over 300whp. Riftswrx is going to run the sti shortblock, ported wrx heads (smaller ports than the spce c heads) and run the fr green turbo, and expects to get full boost by 33-3500 rpm. Russ

What do you mean?? Is it a good turbo? Yep. Can you get better? Yep. I guess it depends on what you are looking to do with your car. I was going to go with a vf34 until I started reading up on the garret/mitsh 16g and 18g turbos. If I had a manual tranny, I would go with the big 16g, and with the auto I went with the 18g. The 16/18/20g turbos are very effecient, so they spool very fast for the amount of air that they can move. With the big 16g you should be able to hold 20psi of boost around 3100-3300 rpm, and the 18g is about 33-3500. Russ

Russ, But how much more Bling Bling $$$ is the big 16g vs VF34? I'm more concern about how long the boost stays on (broad power band)and which one is more effective on a Road Course? Thanks, Chong ps: VF34 cfm?

The VF34 is identical to the VF30 except that it has ball bearings, so CFM will be the same as the 30.

If you look around, you can get the big 16g for around 6-650. If you decide to go down that road, make sure you get a REAL one. Basically it is the same turbo that came on jdm sti's for 93 to 98 or so. Russ

If you want one, you need to be prepared to do injectors (~$300), fuel pump (~$100), and some form of management (~$600-1000). Those things are way more efficient than IHI turbos so it would probably provide better power everywhere, especially midrange and high end. Also, define "too much."

Zola, "TOO MUCH" referring to will my 2.0 be able to utilize this turbo, I have been reading some very good reviews. I have GPMoto equal length headers, TBE, Vishun stg1 flash, but will probably get it reflashed for this turbo, MBC and Boost gauge. Will get fuel pump, and will modify stock injectors. Chong

Do some searching on nasioc for the 16g. There was a couple of good thread that I was reading a while back out these turbos. I am going to run the 18g, but with the auto tranny, my motor jump right up to 4000 rpm, so I don't have to worry about the lag to much. If I had the 5 speed I would be sourcing one of the 16g turbos. The other thing that is nice, if you grow out of the turbo, it is easily upgradeable. I guess the biggest thing is what do you want to do. There isn't a turbo that is going to give you x amount of hp across the board, to gain top end, you losse low end. You just need to figure out where you want to hp/tq to be. If you are looking to get into a good turbo for autocrosses, check out the ion stg1 mods and such, if you are looking to get some good midrange puch, the vf34 or the 16g, if you are going top end power go with the 20g. For each of the turbos I listed, that are 10 more inbetween. Just look at the cfm that the turbos flow, and that will give ya a idea about the hp output. Vf34's with a good tune will get ya close to 300 whp, a big 16g will get ya 300 whp, a 18g will get ya 325 or so (all on pump gas). Joel's vf23 will get ya into the 260-280 whp, with a harder hit down low. A small 16g will give ya the lowe end hit of the vf23 with the upper end power of the vf34. I can go on and on here, just do some searching. Russ

Russ, I already did, I'm infront of a pc all day at work. My next question is where are you buying your 18G for that price. The best I for a 16G found was from Deadbolt for $799 and $899 P&P. Thanks, Chong

The deadbolt 18g is not a real 18g. It uses the p20 turbine housign (ihi housing). I purchase my 18g through Forced Performance in Tx. It was $912 shipped to my door (includes the p&p). You can get the 16g's for around the $600 mark. Russ

Russ, What can you expect out of the 18G you got now as far as performance? And does it have much lag? Thanks, Chong

Expect about 32-3400 to get into the 10+ psi and a little over 3600 for the 20+psi. Of course that depends on the tune and such. Riftswrx got about 300whp out of the one he tuned, and that goes along with what I have been reading about the 18g. Again, if I had a 5 speed, I would go with the 16g. There is only about 100cfm difference between them (on the top end), but the 16g will spool a bit quicker. With the auto tranny and tc mod, as soon as I get on the gas, I am at or over 4000 rpm, so the 18g will give me some quick spool. Russ