After some calulations, speculations, and lots of dull pencils, I think I have found the best compressor for my application..

406 cubic inches, with a redline of 6500. Boost will range from 5-20 psi, and will be intercooled. Propane may come later, but for now, just intercooler.

I have narrowed down my choices to three compressors. Either two 60-1's, 62-1's or TS04's. I hope Monty will chime in, as he is running the 60-1's on his 427....and is making 1200hp on 22psi or so. I would think this would be enough for my engine, but the lookin at compressor maps and plotting point, the 62-1's and TS04's look like they may work better, but as we all know, what works on paper, will never work in the real world...just some strange fact of life.

I was looking at the T61's but I think this will be toooo much compressor for what I am looking for. Maybe not, I am waiting for my turbo book to come from Amazon, but got anxious and want answers now....so please help

Hunter

 

There will always be several turbos that will efficiently and effectively meet the needs of any given application. If you look at the compressor maps of the 60-1 compared to the 62-1 for instance, you'll notice that they are very similar, nearly identical for the most part.

However, my reasoning for selecting the 60-1 over the 62-1 is that I knew that the vast majority of the time my car would be used on the street in "stop/go" traffic, or in residential suburban areas.

Additionally, the high-efficiency of my engine, CNC 18* heads, Hogan's intake, as well as it's displacment were factors. My engine doesn't need alot of boost to make the power I was targeting, but it does need the appropriate airflow. Based upon my previous experience with the engine in it's NA form on the street as well as the dyno, I know how the engine behaved with the rest of my comination and that enabled me to select the best compressor map for my specific application.

Basically, rather than selecting the best compressor map for the high end of my engine's operating range, I chose to optimize it for the low to medium operating range (in the 400-800hp range with the appropriate pressure ratio it would take to make that power with my particular engine), which is where my engine/car spends the majority of it's time due to it's intended usage. In the end though, the differences were very small.

 

Ya I think I will be doing the same kinda matching, using the lower engine speeds, and match those to the compressor map, because as you said, it will be in stop go traffic and **** like that...which aint fun

I have a question about compressor maps. I know that pressure ratio is P2/P1. Also the x axis is the airflow in lbs/min, but the airflow of what? The airflow the compressor pushes at that pressure ratio?
If that is, then I should be trying to match how much air my engine needs with the air flow made by the compressor at a certain pressure ratio right? And for twin turbo apps, the air flow should be divided in two since there are two turbos feeding the engine instead of one.

Hunter

 

Yes, the bottom is air flow in lbs/min. It generally takes 10 lbs/min of airflow to support 100 hp. So 50 lbs/min is capable of supporting 500 hp. If you are talking twin turbos, multiply the compressor airflow by two, or alternatively divide the airflow required to support a targeted hp by two and select the appropriate compressor map.

I mapped out where I am on my 60-1 compressor map, based upon hp and and boost from the datalogging during my dyno runs. It might not be exact, but it does indicate that it's following the peak efficiency island pretty well in the low to mid power levels which is where I was striving to maximize efficiency. in the 600-950 hp range, it's right on the peak efficiency island.

 

also note that monty is running PTEs turbos with the GT350 turbine wheel, which in my research and opinions of others....turbine wheels are what really make the horsepower not the compressor wheel. the better the design the better the spool up and the lower the horsepower and if you have the compressor wheel to match it watch your power climb and climb

the difference between 60-1 and 62-1 is minimal but if you desire it, so be it.

the TS04 i belive, dont quote me, is actually a 60mm compressor wheel but in a T-series type .70a/r compressor housing giving it the ability to flow more air than the smaller 60-1 cover (4" inlet, 2.5" outlet, 9" overall diameter) and the even smaller .50a/r compressor cover (3" inlet, 2" outlet, either 6" or 9" diameter)

 

Thanks Monty for that flow map. I think that I will be going with the 60-1 compressors, they will flow enough for my application.

I know the Turbonetics sells these, and so does Precision, which would be the best? I know Monty you got yours from Precision, what were the options that they came with? I think I want ball bearing turbos, which TUrbonetics offers as an option.

What do you gusy think of a ceramic ball bearing? I would like the faster spool up time, and durability is a huge factor with me. I would like to think that these two factors are the reasons most people upgrade to the ball bearing shafts.

For turbine housing selection, what should I consider? I know these specs affect the backpressure, spooling time and shaft speed of the turbocharger. I would like full spool by about 2800-3000 rpms. What A/R ratio should I choose? I am thinking an .81 ratio but maybe a .96 ratio would be best. Any help is appreciated.

Hunter

 

I decided to go with Precision turbos over Turbonetics, etc because PTE is nearby and the guys at Fast Times have a good relationship with them and have had good first hand experiences. Same goes for Tom at TRZ who helped my build my headers, he has used PTE turbos for a long time as well. Harry and the rest of the PTE crew are actively involved with alot of the teams in NMCA/NSCA/NMRA etc so I figured if all these "big money" guys and racing teams are using them, they are good enough for me.

I think any well-known turbo company is probably a safe bet, and the reality is that most all of them use the same Garrett components, just in slightly different configurations. A few of the larger ones, like PTE do cast their own housings, or machine their own covers and can therefore offer a little additional customizations.

My PT-52's are pretty much the same as what anyone else would get if they ordered one. The did a little porting of the .85 turbine housing for us, but otherwise it's stock. I have done some modifications to them since purchasing them, but nothing that would effect performance. I made housing retainers out of polished .250" thick 6061 aluminum to replace the stock stamped steel ones, and I replaced all the bolts with ARP stainless steel 8mm broached studs with 12pt s.s. nuts, and ARP 3/8" studs and 12pt s.s. nuts to mount the turbine housing to the collector. Most of that was just for aesthetics and corrosion resistance.

On a 406ci engine spooling or lag is not an issue at all, the .85 turbine housing would be a good fit for you as well. I helped another guy, Doug Hegge, get his 1000+hp TT setup started and he used the same turbos and housings on a 375 ci SBC. His experience is pretty much the same as mine - boost by around 2500-3000 if you get into the throttle. The larger hosuings are also more efficient, creating less backpressure.

I don't really have any expereince with the ball bearing turbos. it seems people who ahve them like them, but so would I if I spent the extra money. Personally, I don't think it really matters. If you think they are going to increase durability or longevity, consider that diesel and industrial turbos go for hundreds of thousands of miles, or thousands of operating hours, and the majority of them use a conventional bearing. Using clean, high quality oil, along with common sense has the biggest impact on how long a turbo will last between rebuilds. If you let the oil warm up to operating temp before pushing the turbos, and let the oil and bearings cool down before shutting the engine off to prevent coking, you won't have a problem.

 

I think I will give PTE a call. The 60-1 compressors are what I am choosing, and as for the turbine a/r ratio, I think the .85 will do me well.

I plan on ceramic coating the outside of the turbine housing, using billet aluminum backplates, and a turbo timer, which will be integrated into the Motec EFI system I use, so I won't burn up the bearings after I turn the engine off. Upgrading the connectors is a must, and most of the exhuast related compenents will either be wrapped, or coated to keep velocity high.

I think you are right about the ball bearing turbos.

Hunter