We are working on a project right now and I could use some help from the smart guys on this forum.

Does anyone have flow rates for various turbos including K24/18G, K24/20G, K16 billet, A28s. I am interested in flow rates and compressor outlet temperatures on these various turbos when operated at 1.3 to 1.5bar.

Thanks in advance...

 

Forced Performance doesn't release any maps for their compressor wheels which is what tial use.

So its going to be a bit tough.

 

Not a smart guy but here goes: As you know, this is a big question. Turbo manufacturers will cite ideal/bench test compressor flowrates (or some not at all), but just because a turbo can flow a certain amount at a given pressure ratio doesn’t mean it will on any given engine. You need to know VE of the engine and that can be affected by just about every mod, especially the turbine side. A certain turbo may flow 600 cfm at 1.5 bar gauge (gauge pressure and pressure ratio are a whole other topic but altitude and turbo inlet restrictions have a huge effect) on a stock motor. That same turbo may move 750cfm at 1.5 bar on a motor with headwork, cams, etc.


To give you a general ballpark, at your altitude, the 18g and 20g (assuming the old school non-billet Mitsu wheels here) are off of the compressor map (rpm-wise) producing 1.5bar and ~700hp worth of air. This is because you’ll be running a pressure ratio of around 3.0 to make 1.5 bar at 5000’ of elevation. The BW 2283 billet wheel, 2480, HTA68 and others (common in K16 and K24 hybrids) are more comfortable at these pressure ratios and would probably live around 70% efficiency. You’re looking at outlet temps around 350-375F at 70F ambient and a touch over 400F on a hot day. There are a lot of billet wheels flooding the market now but I would bet any of them capable of making 700-800hp at 1.5 bar (at your elevation) are going to have outlet temps in the 350-375F range. Again, the hotside plays a huge factor.

You can play around with numbers here:
http://www.not2fast.com/turbo/glossary/turbo_calc.shtml
I normally assume a 2-3 psi loss for cars with inlet pipes (add that to manifold boost).
Tack on another 2psi loss across a decent intercooler.

Hope that helps!

 

Thans Earl. I wonder what it might be on my turbos. I have K16 hot sides with ported housings and a 997GT2RS compressor with ported housings. Engine is a 3.8 with high flow heads and it pulls freely to a 7500 redline at 1.3 bar. My altitude is 5200'.

 

My WAG would be mid 300s. That's just based on your IATs and known efficiency from the 997.2s, but also makes sense from the compressor map standpoint (BW2280 compressor is used on the GT2RS).

 

Mid 300s CFM or compressor outlet temp? How much more flow would it be at sea level? Do you have a 2280 map you could post up by any chance. Thx Earl.

 

john ask sean . he may have some details on the k24/billets he makes

 

I would go with bigger hotsides on a 3.8, the K16 based turbos look small to me, based on a generic VE you should get minimal lag and good power all over the rpms band with something like gtx2867 or something equivalent - A28, maybe Efr6758(hot side even bigger)

On the Garrett webside you can look for compressor maps and overlay on a regualar 3.8 engine flow, take a look at my thread here, maybe will help you a bit https://www.6speedonline.com/forums/...ml#post4378703

From the graph above you can see the flow rate at 1.5bar for example on a 3.6 stock engine ( the stock engine is mapped there, not the 3.8.. assume 5-10% more flow on a 3.8 based on work done on that particular engine). look at Garrett website here and get maps for other turbos:
https://turbobygarrett.com/turbobygarrett/
or efr here:
http://www.turbos.bwauto.com/afterma...Reference.aspx

Tial and FP dont public their compressor maps, as stated by Earl

A turbo that can flow high40lbs or so, should be able to give you at least 1.5-1.6bar on the high rpms and like 1.8/1.9bar or even more in the middle range and still not going to overspin or be out of a reasonable efficiency area.

For stock headers I would use the latest A28 turbos - HTA2868 or for more work and power on very high boost - EFR 6758, but EFR might take a lot of work
If going with external gates I would use gtx2867 or even gtx2871 as you might need more compressor flow, taking into consideration your altitude

 

I'm not looking to change turbos, perfectly happy with mine. I'm already breaking wheel hubs and more power would be pointless. I'm limited by the capacity of the MAF so larger turbos would be of zero benefit anyway, just create more lag. Just curious about flow rates and compressor outlet temps...

 

Ok, thought you need other turbos, I dont think a step bigger turbos will have no benefit and also the added lag shouldnt be felt at all considering the bored engine you running.
I would use boost by gear anyway and get advantage of more power in 4th and 5th gears for example

Afaik
K24/18G and A28 should be about 47-48lbs
K24/20G I would expect a bit more but considerable more lag too
K16 should be very limited from the turbine, my guess would be somehere in the mid 30s

If you need a better MAF let me know as I might still have a Ford MAF somewhere that I used on my car before, but going Mafless worked really good for me too

 

John, here are those compressor maps:
2277 -997.1 turbo
2280
2283 -997 GT2 RS (The one that flows the most of these three...)

 

Thanks for the maps Pete. The 2283 is what I'm running. I actually think that the easy answer to my air flow question is to look at logs and look at the amount of airflow the MAF is seeing. If you divide that by half, you will see what each turbo is flowing at any given point in time.

 

I found over the years that compressor maps, better yet, same turbos on different type of cars- lets say a 996TT and a subaru or Evo, do not perform the same way....my point is, especially when it comes to Garret turbos, do not get all excited that XXX turbo on YYY car did ZZZ HP... it just does not work that way. I and Booby have gone thru many turbos on our cars over the years.. and I mean many.... most of it I do not even talk about.
here, I had a evo on a 2L motor with a gt3582R and made 640whp at 30 psi and runs 140 mph.... yet the same turbos at 30 psi can hardly make 900 whp on a P car.... same boost... two 35rs on a 3.6L ( 1.8L a turbos) does maybe 147mph. I mean, its so hard to get real HP out of these cars... let alone run 9s for that matter... something just doesn't add up...

 

Did you measure the backpressure prior to the turbos? Boost level at the intake is a measure of backpressure on the INTAKE side. A more efficient intake side will flow more air and display lower boost IF the impeller spins the SAME speed, but make more power so long as the exhaust supports it. That doesn't happen though, turbos will simply spin faster as intake restriction is removed thanks to the wastegate, while making more power, and show the same boost. Intake pressure is actually pretty meaningless...

This is easiest to see with a pulley driven blower and I witnessed it myself on a Mustang with a centrifugal blower. I had a blower on it making Xlbs of boost but wanted more. Had headers, a ported intake, and seriously ported heads put on it. Driving the car it made several lbs LESS boost but was significantly faster. I was upset at first seeing less boost but I was ignorant and didn't understand that airflow was significantly better. Afterwards I always chuckled pretty good to hear other owners bragging about how much boost they ran as if that was a measure of power when other changes were made. With a turbo you continue to see the same pressure level but the impeller spins harder, it's one of the things I love about turbos :-)

 

A website I've always found helpful...

http://stealth316.com/2-turboguide.htm

Compressor flow maps are at the bottom for the TD05 18G and TD06 20G. Also has a variety of measurements for the compressor and turbine wheels for a lot of different turbos. Based on size, you might be able to come up with a reasonable estimate for the A28's.