this is a great reference i found on srtforums.com
There is no perfect turbo for your car. You cannot just look at a map and motor and say "this is the perfect turbo" and expect it to work for everyone. If you want to autocross, your turbo will be different from someone who is roadracing, who is drag racing, who is street racing, who is just wanting a fun car. This is why there are so many turbos and selecting the right turbo is important.
Bigger turbos flow more air, but due to the size, take longer to spool. By matching the correct wheels and housings, you can minimize lag, and still make good power. All numbers given are best case scenario. Many things can affect power. The HP numbers are at the extreme limits of a turbo and not to be expected for everyone. Remember the parts are only as successful as the person or persons installing and tuning them.
50 Trim
Good all around turbo. Spools fast, and will make good power. Loves lower boost levels and lower octane gas. If you plan to run nothing but pump gas, and want a good street turbo, then this is your turbo. Full boost should be right around 3100-3200rpms.
DBB 50 Trim
This is a standard 50 trim/stage 3 setup using the garret GT style dual ball bearing center section. This gives you quicker spool, and faster transient response with the same great proven 50 trim combo. This turbo is quickly becoming the a popular choice for a great street/strip combo. The lag is only slightly more then many small turbos.
57 Trim
57 trim is not a well recommend turbo . Its basically a less efficient 50 trim. Other shops will tell you that a 57trim is a larger turbo than the 50trim, but it is not. (remember trim is a ratio not a size) 57 trim spools slower and makes less power than a 50 trim and also has been known to surge on applications. If you want something that spools faster than a 60, then get a 50 trim. If you want a bit more power, get a 60 trim.
60 trim
Slightly larger than a 50 trim. Will support another 10-25hp. Slightly laggier. Full boost around 3200-3300. Will make over 30psi and also a good street turbo. Likes higher boost. Below 20psi, at the same boost, a 50 trim will make more power, but at higher levels, the 60 trim has a slight edge. Good overall turbo. Strong top end
60-1
60-1 can make well over 500whp, support 32psi, and be a nasty turbo. Full boost is around 3400-3500 in a .63 A/R turbine housing. This is a good race turbo but on pump gas is much less efficient than the 50trim. You wil need a built motor to take advantage of the extra power this turbo will make. At 30psi it will make 40-50hp more than the 50 trim but at 20psi will usually make ~20hp less. This turbo is ony recommended if you have a built motor and care more about race performance than street performance
A/R ratios
This relates to the internal volume of the turbine housing. A larger a/r will flow more air, support more power, but spool later. For almost all applications we suggest a .63 a/r. All the numbers quoted above are with a .63 a/r. We us the new 4 bolt housings that flow better than the 5 bolt housings. A .48 is suggested if you want fast spool. A .48 will still make over 400hp no issues. I would run a 50 trim/.48 so the turbo comes on fast and hard. Full boost would be under 3000rpms. This maybe too fast for alot of people that want traction. .48 would be good for roadracing/autocrossing and good flat power bands.
Spool time
Spool can vary from car to car. There is no hard number to give. The condition of the motor, intake, exhaust, tuning and tons of other factors affect spool. In lower gears, the turbo spools slower. Spool numbers are normally quoted time to max boost in 4th gear. The turbo usually is pulling hard 500-600rpms before max boost as boost is coming on. Take this into account when looking at spool numbers.
GT Ball Bearing Turbos
These turbos are meant for high boost, high RPM racing applications. For lower boost levels, and street applications, a conventional t3/t4 turbo is probably better suited for your needs. The difference between spool time in a ball bearing and normal bearing on the same size turbo is small. Transisient response, or between gear boost is improved, but a properly sized turbo shouldn't have any issue spooling between gears. GT series turbos normally run smaller turbine wheels, which lead to somewhat high backpressure when not placed in a larger volute turbine housing. I recommend a standard bearing turbo and spend the extra money on the supporting parts. One of the main advantages to a ball bearing is the increased load the bearings can take. If you plan on higher high boost all the time, a ball bearing will take it all day long. For a turbo that hits fast, reliable, and can make big power, a dual ball bearing GT turbo is a great option.
I hope this helps out alot of people on the org when they deide to bost there J !!!!!!!
holy subjective information batman.... first off, i'm not trying to bash your work here, and a good portion of what you say is GENERALLY true, but the only way for someone to really properly match a turbo to their application is to do a compressor match using a factory supplied compressor map. And the GT series are far from being a race only turbo, and are used in street applications more often than not. However, you are correct in that they are best used for high boost.
But when it boils down to it, the best turbo for any given application is the one that best stays in the efficiency range of the compressor map at the chosen boost level and powerband for the engine's ability to flow air... Having a ported head, cams, any of this can completely change which turbo works best. Beyond that, you leave out the standard T3's like the Super 60 and the 60 trim, which are probably the best all-around street turbos for the 2.2's (both ohv and eco surprisingly enough). Not to mention a total snub of the mitsu turbos such as hahn uses, the 14g, 16g, and 20g.
Although the pics are now dead links,
The Flying Squirrel's thread on turbo matching is probably the most specific on this forum as to choosing a turbo for a set application. Granted, the calculations are only as accurate as the info entered, but thats the right way to do it.
You say that you can't just look at a map, and a motor, and know the best turbo, and you're absolutely right. You need to gather the data on your motor to know at least approximately how efficient it is, and also to know how much power you want and where you want it. With that information, plotting compressor maps for several different turbos WILL show you which one is best for the application you want to use it in.
Again, not to belittle what you've done, and you do make some good points, but when you give advice to others and state it as if it were fact, it should be objective and based on the proper evidence, not just opinion.
Arrival Blue 04 LS Sport
Eco
Turbo
Megasquirt
'Nuff said
im not at all the writer of this threads info, i was researching turbo facts and just finding out what everything means , and i found this great post on the srtforums.com with great information that helped me out deciding what turbo size i should run and what all the a/rs mean and spool and such and such, im by no means a veteran on sizing, i just thought this was a great piece of info and i wanted to share with everyone on the .org this info
the write up was originally done by Chris at AGP turbo.
but more great info you added Scarab!! i just learned some more from you
thanks
Quote:
Although the pics are now dead links
yea i can't edit it to fix it either.. oh well
Quote:
m not at all the writer of this threads info, i was researching turbo facts and just finding out what everything means , and i found this great post on the srtforums.com
ah yes.... that would lead to a problem... being:
1)Different Shortblock (mainly diff compression ratio, but the SRT4 shortblock is way stronger than the chevy 2.4 and stronger than at leas the 2.2 eco rodswise... 2.2OHV, well, that goes without saying).
2) Different Head (i'd bet there's a pretty decent difference between cam profiles and port sizing/shape).
3) Its on SRTforums.... while at least its written by the owner of a shop, its still sketchy enough for me to question if i'd bring my car there for work... (of course he could have been oversimplifying it for the ease of the layman... although the layman should not be upgrading his turbo if he can't understand the correct way to select a turbo). Not to start this argument again but most of the SRT4 guys that i've met in person are 17 year old kids who don't know the first thing about forced induction or tuning. Granted not all of them are like that, and I hope its not the majority nationwide, but its been the majority of them that I've spoken two while racing for the last year and a half, and working at a Dodge dealer as a tech for 3 years... So I'd be pretty wary of anything off of there if you're just starting to learn about turbos.
Do yourself a favor, look at what the fastest guys at the track are doing, and try and copy it. There's no shame in copying a quality setup that works and its better than having an original setup that sucks.
Arrival Blue 04 LS Sport
Eco
Turbo
Megasquirt
'Nuff said
