I wanna know what size turbo most of you guys are using? Do you get pretty good boost? Im kinda looking for something that will boost from like 3500 to 6000 or so. Any suggestions??? Thanks!

 

a t23/511 with a 2.9 A/R compressor side should work well and a 4.8 turbine side, that thing is a BEAST!!!!

 

For the compressor side go with something in the range of a TO4B 50 trim, TO4B 60 trim, or T60-1. These will work quite well with the flow requirements of the 3.0L VQ.

For the turbine side, go with something like a T3 with 0.63 A/R turbine housing to spool around ~3500 RPMs or with a T4 with 0.58-0.68 A/R turbine housing if you don't mind waiting till ~4000 RPMs to spool.

If you don't know what the hell I am talking about, then do more research. Turbos aren't simple bolt-ons.

 

I've got a .84 A/R T4 with a P trim and I see 10psi by 4000 in 4th gear, boost onset is 2700rpm. I30tMikeD has a .70 A/R T4 with a P trim and spools at 3500 and has full boost (10psi) by 4500 in 4th gear. MardiGras with his 3.0L setup .58 A/R P trim saw boost onset at 3450rpm and 6psi by 4000 and 9psi by 4400 - all in third gear. You'd have to have a pretty asinine piping setup to not even start to spool by 4000rpm with a .58-.68 A/R T4 unless you are talking about 1st gear. Heck even maxmaxima91 with his MASSIVE 1.32 A/R T4 and P trim sees his full 13psi by about 4500 if I recall what he told me correctly on his old tired 1991 VG 3.0. It's all about the piping.

 

We need to agree to common terminology. When I state the turbo is spooled, I mean it has achieved its boost target (a "high" target might take an extra 100-300 RPMs to reach over a "low" target; however, I am just providing ballpark info). I do not mean the onset of boost.

I was also thinking about 4th gear roll values from low RPMs (< 2000), which are what should be used as a common metric IMHO. The difference in boost vs RPM is of course very large even between 3rd and 4th gear on the same car.

 

My inlet side is a .65 A/R, my exhaust side is 1.1 A/R. Is this turbo good enough? I kinda wanna start to spool at about 3k to 3.5k until whenever it can go...

 

That tells me nothing without knowing what your compressor size (actual inducter/exducer dimensions or "TO4B 60 Trim" type of info as examples) and turbine size (T3 or T4) and turbine wheel type (O-trim, P-trim, stage III, etc) and turbine housing A/R (0.42, 0.58, 0.63, 0.68, 0.81, 0.96, etc).

The turbine (wheel + housing) is the dominate factor in when you will spool the turbo. The compressor size does matter somewhat due to larger compressors having higher moments of inertia, which take more power to spin up. Think of the turbine wheel, the shaft connecting it to the compressor, and the compressor as one unit. They are mechanically linked together and spin at a 1:1 ratio to each other. To achieve boost this entire unit must be accelerated to somewhere between 50,000-100,000 RPMs. This will require a certain amount of energy.

If you increase the MOI of the compressor you will slow the acceleration and delay spool. If you change to a smaller turbine housing you are increasing the power generation of the turbine and increasing the acceleration and thus moving spool to a lower RPM point. However, if you have too small of a turbine housing/wheel, it can be incapable to providing sufficient power to spin the compressor to sufficient RPMs to produce higher boost targets or you could be choking the engine on the exhaust side. It is all a trade off.

Finding the happy medium is the key. The best way to do this (turbine selection) is based upon what others have done and what there results were. The engineering way to do it isn't simple (the method involves an iterative technique).

In general, you pick your goals for power level and boost response and then pick a turbo that will acheive them. It is very unlikely that the turbo you are describing will be a good fit. If it is a T4 turbine, then you are looking at 4k+ before spooling.

As an example, my mildily modded 5.0L mustang has a T66 (66mm inducer on the compressor) with a 0.68 A/R T4 Turbine with P-trim wheel. I get 8 PSI by 2800 RPMs and 13 by 3000 RPMs. So if you do have a 1.1 A/R T4 turbine/housing it is pretty much certain that you are not going to get your boost response target.

 

Yeah i kinda understand. The turbo is a Garrett T4. I dont know what kind of trim it is. Im guessing im gonna have to call them with the s/n if that would help... Any suggestions?

 

Did you buy it new or used?

If it is not some oddball turbo, you can easily change to a 0.58 or 0.68 A/R housing for cheap (my new 0.68 A/R p-trim turbine housing only cost $65)and greatly improve the spool (I doubt it will get full boost before 3.5k though). This is if of course the compressor is a reasonable enough match to use.

I would ask them specifically the questions I mentioned to you. The s/n doesn't tell me anything.

 

Where did you get that (.68 housing for 65.00) from?

 

http://www.boostedsystems.com/index.php?cPath=22_30

I have no idea why he lists them on the website so high. I did mention that I was a Turbomustangs.com member to get that rate.

The Master Power turbos (and other parts) are high quality Brazilian turbos of compariable quality to Garrett, Precision, etc.

Just call them and ask for Joe.

 

Thanks for all of your help. I will see if i can do that.

 

FYI

I added some relavent info to post #7 related to the turbine and spool.