T4 compressor size

[ZVOLV]

Ok, i am buying a t3/t4 ASAP. What trim compressor should I use? I was told by my ford buddy that 50trim is what I should use since he knows that works well on the 2.3 fords. After looking at the maps I am unsure what I should use. I cant tell if I should use the .46 trim or the .50 trim. Maybe even bigger....

Where is Philip Bradley? I know he has messed around with different trim t3/t4's and I love his advice since he is mature, knowledgeable, and modest.

I followed the formulas from sport compact car's sep 2001 article on compressor maps and i got 25.3 as my Corrected Airflow. That was using 6k redline, 15psi, and 80% VE. So with 25.3 airflow and 2.12 pressure ratio (15psi) I am looking at the maps. Here is are the maps I am referring to. http://innovativeturbo.com/cgi-bin/h...65933637923603

Please let me know what compressor you think I should use. I am asking people who have had experience with t3/t4s on volvos or who have a strong knowledge in compressor sizing.

[ZVOLV]

I will probably be running 10psi so the numbers for that figure are 21.1 and 1.78 so the 50 trim looks about right on for 10psi.


What CMf have you guys calculated for our motors?

[Matt Dupuis]

Why would you run only 10 psi on a T4 compressor? You ain't gonna see any improvements with that big of a compressor if you're not flowing enough to take advantage of it. A T3 is more than enough to deal with your airflow... A T3-60 trim is good for your application, based on the guidelines. But in reality, a T3-50 trim is probably perfect 'cause you'll be in the sweet spot 99% of the time, you cross the surge line at about 2000 RPM, and there's only about a million of 'em in junkyards. If you're planning on upping boost, you could do a 60/63, but I would NOT go for a T3/T4.

IMHO, T4s are designed to be used in a balanced flow application - I'm not sure if that's the technically correct term and my books are at home so I can't look them up, but when those turbos were new, wastegates were optional and you didn't make boost before 3/4 of the way to redline. Boost went up with RPM, so the line you drew on the compressor map angled up and to the right, along the long part of the island. With a wastegate, your pressure ratio stays constant, so a flat line across the map. Using a T4 compressor with a wastegate gives you a VERY narrow band of efficiency!

If you look around you can find maps for HX and HY-35 Holsets. That's what a modern compressor's map looks like!!! It's super wide between 1 and 2 bar, so with a properly sized wastegate it'll be very efficient over a wide RPM, keeping your compressed air cooler, giving your intercooler less responsibility.

BTW - I've found an error in SCC's articles before. I don't remember what episode it was, but I remember it was significant. At 10 psi, using the equations found in Turbocharging and Maximum Boost, you're passing about 23.5 lb/min at 6000 RPM and 80% VE. Keep in mind that VE value is VERY ROUGH!!! It's a good guideline, but in reality it's totally dependant on your cam, compression ratio, exhaust & intake breathing, etc. It's probably nowhere near 80% at redline, closer to 80% at your torque peak.

[Pennybridge Pioneer]

shane went with a super50E comp wheel, he seems to think its pretty slick

i was looking at maps a couple nights ago and actually the 57trim looked more suitable for our motors, i was just looking at the intersection of 25lb/min and 2.00pressure ratio, i know its more complicated than that, but i'm not laying down cash anytime soon. take a look at a 57trim map when you get the chance.

what matt is saying about the width of the map makes sense, but i don't really understand them enough to agree or disagree. All i know is that plenty of people still use t3/4's (with wastegates ) and get good results. At least one MVP guy is using a t3/04e and we know they get results. Lots of people, especially in sweden, use holsets because of their "modern" design and they are readily available for decent prices. There's a reason the turbo companies still sell almost exclusively t3/04's.

I know innovative makes a couple turbos using the new garrett GT comp wheels, which are supposedly very superior design to the old t04e comp wheels......

[socalsean]

Talk to MACH375. He's got the knowledge and has a t3/t4 on his 740.

socalsean

[ZVOLV]

I think i am only going to be able to run 10psi before fuel cut. I will run 15-20+ when I get my EMS.


The 50trim looks about right after all.

[the poi]

you should probably take care of fuel (and even ignition) management before you start throwing a bigger turbo on your car. Theres just no point in a bigger turbo without a motor that can use it...

[ZVOLV]

True, point taken. I already know that. I am getting both VERY soon. I just need the turbo ASAP.

[Captain Bondo]

57 and 50 are both good choices. The 50 is the best but 57's can often be found cheap in my experience. I ended up with a 57t4/0.63 a/r t3 hybrid with a stage 3 turbine wheel. Also just wanted to say this thread is hilarious on many levels and in my opinion you're wasting your money at this point. But have fun, anways.

[ZVOLV]

Apparently the 57 is cheaper and more common for whatever reason. It also seems that the 50 will be more versatile. The 50 is ordered and will be here mon or tue.

[Captain Bondo]

Cool- where from? Specs?

[Pennybridge Pioneer]

Originally Posted by Green Death

Also just wanted to say this thread is hilarious on many levels and in my opinion you're wasting your money at this point. But have fun, anways.

care to elaborate?

"care to elaborate?"

Oh just a tongue-in-cheek thing from days gone by...

On topic
Just some comments for Matt:
(With all due respect, of course. ;))

regarding the Holset maps- I'm quite sure those maps are designed to represent a RANGE of apps and are not maps of a single compressor wheel. Holset's words not mine.

Regarding wastegate T4's:
Assuming you select a wheel with a reasonable pressure ratio, the whole "narrow efficiency band with a wastegate" seems a little hard to swallow as I cruunch the numbers.

For example with the T4e50 at 1.4bar the efficiency goes from 68% to 78% and back to 68% between 200hp and 400hp. Come on, a 10% variation over 200hp? I think most people can live with that....
The 57 trim varies from 65%-78%-65% between 200hp and about 350hp at 1.2bar Unless you have a good flowing head it gets surgey beyond that. So a 13% deviation over 150hp- starts to show the 50 trim's superiority. But regardless neither is bad assuming you have the supporting mods and NA flow to keep surge in check and most importantly that you be strategic regarding pressure ratio.

The other side of the coin is that good IC function flattens that deviation even further. I can see what you're saying about following the length of the efficiency "island" but on an intercooled car 10% deviation of 200hp makes your post seem like it might be overstating the issue. Just MO.

We all have our opinions regarding turbo theory, etc. but just suffice it to say nothing annoys me more than that misleading SCC article.

[ZVOLV]

i just used that article for the formulas. Are they wrong? One guy told me a really easy way to read compressor maps in a general way: Y axis is boost in bar and X axis is desired HP. It was roughly the same as the numbers i calculated. Also, there were so many steps, rounding, and estimations (IC pressure drop, intake air temp, VE, etc) there is plenty of error in the calculations. Thats why i asked what numbers you guys have for corrected airflow.

My buddy who is a distributor for innovative was the one who told me the 50 was more efficient (meaning over a broader range) than the 57. He was also the guy who said the 57 was cheaper. I havent done much research, but at least on ebay almost all the kits are 57 compressors and all the ricer turbo kits are 57. My buddy also said people even have had experiences buying what they thought was a 50 and later it turns out it was a 57. I am just spreading a rumor, but as far as I can tell its true. It makes sense since the .54 seems to operate over a broader range it might be a 'better'/'more expensive' compressor.

[WeezilUSA]

Wait, so you want a hybrid turbo to run 10 psi of boost? WTF?

[ZVOLV]

Originally Posted by WeezilUSA

Wait, so you want a hybrid turbo to run 10 psi of boost? WTF?

Hell no. I just think that will be all i can support daily until I get my EMS.

[Matt Dupuis]

Due respect accepted, and returned:

Originally Posted by Kenny

regarding the Holset maps- I'm quite sure those maps are designed to represent a RANGE of apps and are not maps of a single compressor wheel. Holset's words not mine.

Was not aware of that. Why oh why are they so elusive with information???

Originally Posted by Kenny

For example with the T4e50 at 1.4bar the efficiency goes from 68% to 78% and back to 68% between 200hp and 400hp. Come on, a 10% variation over 200hp? I think most people can live with that....

I'm not gonna argue this - you're right, but when you look at the amount of air this engine will actually use, it doesn't cross the surge line until fairly high (unacceptably high to my tastes) in the RPM range, and only comes into full efficiency when the engine is at redline. The engine spends so little time at redline and is so naturally inefficient there, why size a turbo for that RPM?

I realize that I didn't say "crosses the surge line late and gets to max efficiency by redline" instead of "narrow efficiency band", but it boils down to the same thing. Of course, I also should have qualified my statements with "small displacement engines", because of course engines flowing more air through them are going to be happier with a T4 than a T3, because they will stay on the "good" side of the efficiency line for longer.

When I posted, Guidom didn't state that he wanted to add EMS or anything else in the future - he asked for advise on the sizing of his turbo based on the numbers he gave. I gave my opinion based on that information. We were only talking about a 250 hp motor at .8 bar, not a 400 hp motor at 1.4 bar. I still stand by my advise, that a T4 is terrible for a 250 hp motor, unless you have a case of bigdickitis (or you plan some major upgrades damn soon).

Originally Posted by Kenny

The other side of the coin is that good IC function flattens that deviation even further. I can see what you're saying about following the length of the efficiency "island" but on an intercooled car 10% deviation of 200hp makes your post seem like it might be overstating the issue. Just MO.

Absolutely true. If you consider the IC a pure energy dissipator, it should get rid of quite a bit of that extra heat, but some is still going to get through. I don't want to get into an intercooler theory discussion, so I'll just leave it at that.

[pbonsalb]

A 0.63/60 trim T3 will support 275 rwhp. Bill Watson uses two of them on his 550 rwhp twin turbo Ford Mustang. He has done all sorts of backpressure and efficiency testing and is not particularly worried that the turbos are choking the exhaust or producing superheated air. The turbos have been on the car for a couple of years.

Would his car go faster if he made 550 rwhp with 0.63 stage III T3/54 trim T04E turbos? Would he make the same power with significantly less boost? Would he make significantly more power with the same boost?

I have been using a 400 hp capable turbo for over 5 years now and still haven't broken 250 to 275 hp. I could have enjoyed a broader power band had I been more realistic. Maybe this year I will actually need the extra airflow. I say that every year. The header, external wastegate and programmable fuel injection that are going on the car this year make it look more promising, however.

Consider whether your power goals are turbo limited, other bolt on part limited, engine management limited, engine block limited, engine head limited, transmission limited and fix what is necessary.

Philip Bradley

[linuxman51]

it boils down to this:
run the numbers yourself, figure out your projected air flow, and then haggle with yourself over a turbo.

You will, however, find that "standard" sized t3/t4's are generally cheaper and more plentiful..

for instance, you can snag brand new 57 trim examples off heebay all day long for $400.. And they work, and work well.. eric simpson has one on his ride and seems to love it.

but the bottom line is, you're gonna hafta run the numbers yourself and then take responsibility for what you get, not trying to be an ass, just simple facts. Do the reading, run the numbers, and decide fo yo sef

[ZVOLV]

I ordered an innovative brand t3/t4 and I have been told that it already has an enlarged wastegate hole. Now I gotta find a wastegate....or a way to mod the t3 one. What do you guys think I should do.

I am also going to use the ford wastegate housing since it looks less restrictive and I can eliminate that crappy flared tip and 3 stud design. Mine leaks. It appears that it opens right up to 2.5 or 3" right after the turbo and doesnt route the gasses up to the outlet hole, but instead is just wide open after the turbo. (At least the setup my buddy has)

[pbonsalb]

Either the Volvo or Ford wastegate housing should be cut off and a 3 to 4 inch pipe welded in its place. The Volvo housing is significantly higher quality than the Ford in terms of metal strength. Further, the Volvo housing has a larger flapper valve than the Ford. The welding needs to be done by an expert. Cast iron is tricky to weld properly. It is time consuming.

Philip Bradley

[Pennybridge Pioneer]

did you happen to buy this turbo from some guy at honda-tech? "camp1234" or something?

[Captain Bondo]

Matt,
ok cool. In the context of using a T4 on a 250hp engine your comments make sense.


The formulas from SCC are fine. A formula is a formula. A dead string of numbers unless applied properly. A person can have every formula in the world and if they cannot apply them correctly they mean very little. It's not the formulae I disagree with so much but rather the interpretation and application of them.

If you bought the right turbo should not have to "modify" anything for the wastegate. If you bought a hyrbid with a 5 bolt turbine housing exit a Volvo wastegate will bolt right on. It bolted right onto mine anyways... how you choose to mod it is another thread.

Cool discussion.

[Pennybridge Pioneer]

k so to go in another direction, how does, say, a 50trim t4e compressor/ .63 t3 turbine compare to one of the popular Holsets? I suppose if doug could chime in here (or Oskari if he's around) why go with the holset over a t3/t4.... can someone in the know compare/contrast the characteristics of a properly sized holset with a properly sized t3/4, maybe for an 8v b230 with normal supporting mods...MSnS...aiming for around 300hp?