pianoprodigy

When I purchased my car, I was told it had a Turbonetics T66.

I looked up the map and had absolutely no idea what I was looking at. I've done some reading and figured out how to determine boost (Y-axis) which I have marked on this map. I understand the X-axis is flow, but how do I know what my flow rate is? Is there a standard flow for a stock port? I have a "large streetport." What should I estimate my flow to be?

I'm going to the dyno FINALLY to tune for more boost next weekend, and I'm just trying to get an idea on what to realistically expect. I'm planning on having it tuned for 20 psi. I have been saying for a long time that I expect to make 500whp at 20 psi, but I just wanted to see if I'm smoking crack or what...

Anyways, here's the map with my boost markings...

the_glass_man

iTrader: (2)

You're smoking crack!

nyt

iTrader: (1)

your Y is wrong.

1.96 = 14psi
2.24 = 18 psi
2.37 = 20 psi
2.93 = 28psi



that turbo on a well ported motor can make 500rwhp at 20psi.

your flow will be around 60lbs/minute.

gergrx7

This should help you learn to read compressor maps better

http://cybrina.mine.nu/MR2_Docs/comp..._flow_maps.htm

Carl Byck

From the few high boost T66 dynos I have seen, and trust, a 1.0 Q trim T66 is good for 500rwhp@ 25psi. 1.0, and Q trim, are both on the big end in terms of T66 specs, so unless you have a much larger hotside(big lag) I think ~450 is closer to reality. As you know, I have a T66 .81 Q trim. I chose this turbo hoping that the smaller AR would help my spool, and the Q trim would give me the flow to offset the smaller AR. Unfortunately my car is still untuned, and I do not know what my results will be. There are some very big HP cars running T66s with the 1.0, or even larger, and making well over 500, but I think they are closer to 28psi, and perhaps some spray on top of that. So, if I remember, we do not know if you have a P trim, or a Q, I believe you speculated a .96 P trim. If this is the case, with a largish street port, proper fuel /manifold/ignition/tuning and exhaust, I'd say 450 everything perfect,425 with one or two minor issues. Good luck, and please correct my assumptions as appropriate. Carl

pianoprodigy

Carl,

I knew I could count on you for input on a T66 thread! My car made 360whp at 13 psi and 410whp at 16 psi. That's a 50whp gain for 3 psi. I have assumed that the turbo would at the least gain the same hp/psi from 16-20 as it did from 13-16 which in this case would be about 16.6 hp/psi. 16.6 hp*4 psi=~65hp. Therefore, I would think based on these quick-and-dirty, non-scientific calculations that I should make a minimum of 475whp at 20 psi.

Would you agree that regardless of the version of T66 that I have that I would make at least the same hp/psi from 16-20 as I did from 13-16?

Wargasm

Oooh, this will be fun...

I'm going to say that at 20 PSI, you make 453 rwhp and here is why... I'm no expert, but here's my logic...

Referring to the diagram below... We can guess that a non turbo FD might make around 180 engine horsepower with mods like a port and headers. Let's put that on the graph as pressure ratio = 1 and flow = engine hp/10 or 18 lbs/min.

Now, put your other two points on there. The pressure ratio for 13 PSI is (13 + 2 + 15) / 15. The extra +2 is for the pressure drop though the IC and pipes and I am using 15 because 14.7 is annoying. So we've got 2.0 and a rwhp figure of 360 which works out to around 420 engine HP. Put that point on there.

Put the 16 PSI point on the graph in the same way.

Connect the dots and extrapolate. (Here's where I"m making a big assumption!)

20 psi = pressure ratio of (20 + 2 + 15) / 15 or 2.46 and then you figure out the engine hp is around 533... so figure 15% drivetrain loss... 453 rwhp at 20 PSI.

Am I right? We'll see when you turn it up to 20!

nyt

iTrader: (1)

a lot of it will depend on his tuning/timing. between 450-500 is almost definite though.

twokrx7

iTrader: (1)

I'm with Carl on this one, it's all about exhaust restriction and porting when you try to make 450 to 500 rwhp on the T66. If it's a small A/R p-trim hot side the exhaust may be limiting to well below 450 rwhp (depending on manifold, porting, exhaust aft of turbo, etc, etc). Upping the boost past 15 psi may net much less than upping the boost below 15 psi.

The compressor map can get you to 500 rwhp.

pianoprodigy

Interesting. More "lower" estimates than I expected. Anyone else?

nyt

iTrader: (1)

you made 410rwhp @ 16 psi.... dont see how 4 psi is going to give you 90 horse

the_glass_man

iTrader: (2)

pianoprodigy

I didn't say you were wrong. I think 475rwhp would be reasonable though. That 410rwhp number was done in 90 degree ambient temps as well.

Carl Byck

If we knew AR, and trim, we could get closer, certainly 16 psi is on the low end for a T66, Your gains from 16-20 per psi should equal those from 13-16 assuming that you hava a large enough AR/ Q trim. If it is a P trim, then you may fade to ~10-12hp/lb, as opposed to a Q trim, wherI would try to take it all the way up to ~25 psi and expect to continue to see sold gains all the way up. Carl

pianoprodigy

Anyone have a quick explanation or a link to something that explains P & Q Trim?

Carl Byck

Since I cannot edit my post, "sold" should say "solid", and "wherI" should be "where I"

I have the specs at home, but if you spend some time searching "moreboost.org" you will find the exact specs for a Q trim vs a P trim. basicly, it is a difference in the ratio between the inducer, and the exducer on the turbine, the Q trim outflowing the P trim. In theory the flow improvements will offset the slower spool of a Q trim, ie the increase in flow will yield more HP/TQ at a given boost than the perfomance that is lost due to a slower spool. I am almost positive that the wheel size inducer/exducer on a Q trim T66 is the same as one of the more popular 40R trims. It would require removing the turbo, and measuring the wheels to determine which youhave, at which point I would just dyno the thing, and keep upping the boost so long as you have no problems with AFRs/EGTs/ignition. Personally, I would tune my AFRs fairly conservative(10.7-11.0:1) after that if everything is working perfect, I would use timing to tune for max torque. I would use C16 while tuning to safeguard against screw-ups, I do not subscribe to the belief that you should tune with the octane you will run, as I do not believe that a car tuned on say C16 will behave signifigantly different, when it is run on 100. The C16 simply safeguards against oversights that tend to occur after making alot of changes to your set-up while on the dyno.

pianoprodigy

Yeah, I think I'll just dyno it and find out. I would like to know my setup better, but it probably isn't worth paying my mechanic to take stuff apart when it is working fine. I plan on running at least 110 octane when running 20 psi for safety both on the street and on the dyno. My tuner has assured me that my timing is conservative, and he knows that I would rather make a bit less power and gain that safety net. Hopefully, the weather will stay out of the 80s next week so we can get to the dyno.

diyman25

some Q to ask.

From my research. The T66 is very close to my HKS T04R. but from what i seen. THe japanese never talking about which "TRIM" they have. meaning O,P,Q trim. instead they have number ? my HKS T04R's trim number are Cold side 63 trim. hot side 76 trim. can any explain to me a little bit of this ?

Wargasm

When people refer to "trim", they are sometimes talking about 3 slightly different but related things:

1 - As I understand it, the correct definition of trim is the diameter of the small side of the wheel squared, divided by the diameter of the large side of the wheel squared, then multiply by 100. So, for a wheel with a 2.324 inch inducer and a 3.000 inch exducer, you get: 2.324^2 / 3.000^2 or 60 trim. Hopefully I'm not wrong here ehhe

2 - Sometimes people refer to P or Q trim wheels. This is commonly used for the T04 family of turbines. Saying "P" is a lot easier than saying "Yeah I have a 2.544 inch exducer and a 2.922 inducer". Just saying P or Q is a lot easier.

3 - Sometimes people refer to a wheel size as trim. For example, Garrett lists TWO compressor wheels for a GT40. There is the 88 mm wheel or the 82 mm wheel listed. So, someone might casually say, "yeah I have a GT40, 88 trim"... or perhaps "I have a GT4088". Those numbers are NOT the trim! They are the measurement in mm of the large side of the wheel.

4 - I've even read posts where people say "trim" when they mean "A/R"...

Anyhow, as you can see, there are a lot of terms thrown around and you have to be very specific when you are looking at turbos to be sure you get the one you want.

B

Snook

iTrader: (12)

everything has to be just right
I think usually we overestimate what hp it'll make.
supras can make 475rw at 18psi on that turbo so expect 450@20 if it goes well

are you just going for a number or do you feel that the car isn't fast enough for you right now?

pianoprodigy

Several factors have influenced my decision to "up the boost."

My car needs to be retuned for 16 psi after changing fuel setups. Since my external, noisy-as-hell SX pump died and was replaced by dual, in-tank Nippodensos, anything more than 15 psi gets nasty breakup above 6k RPMs. Since I'm going to be paying for dyno time anyways, I figure that I might as well explore the potential of my engine porting and my single turbo. My tuner and I have decided that 20 psi is the boost level he'll tune for. I'm also, of course, interested in going faster to beat some of the super fast 03 Cobras & Built LS1s with N20. I've been waiting through all the hot months to go back to the dyno so that the ambient temps won't be in the 90s. It also would be nice to be able to say "Yeah, it has 600 horsepower" (but I would need 510 whp for that, so I'm not holding my breath).