How do you read a compressor map?

[glhsken]

Little known fact.. Larry ONLY dynoes his car on days the "elevation" is below sea level... That's how he makes those #'s

[4sfed4]

Quote:

Originally posted by glhsken Little known fact.. Larry ONLY dynoes his car on days the "elevation" is below sea level... That's how he makes those #'s

HAHAHHAHAHAHAHA!

The real reason for the numbers......16V power!

[theskeptic]

Ok, I got it.

So, when I see that I'm going to be pushing between a 2.7 and 3.0 pressure ratio I know that my 60-1 compressor is highly inefficient at that point.

I'm shooting for 400 hp at the crank at a 3.0 PR, what would compressor would be most ideal?

-Dana

[4sfed4]

Quote:

Originally posted by theskeptic I'm shooting for 400 hp at the crank at a 3.0 PR, what would compressor would be most ideal? -Dana

For a street car, Id probably stick with the tried and true TO4E 50 trim (probably the Super version) for that power level at that PR.

http://majesticturbo.com/20576.html

[4sfed4]

Quote:

Originally posted by theskeptic Ok, I got it. So, when I see that I'm going to be pushing between a 2.7 and 3.0 pressure ratio I know that my 60-1 compressor is highly inefficient at that point.

Your 60-1 will curse your name out loud if you try to make it move "only" 400 hp worth of air at a 3.0 PR! I think it will most likely surge.

[theskeptic]

Quote:

Originally posted by 4sfed4 For a street car, Id probably stick with the tried and true TO4E 50 trim (probably the Super version) for that power level at that PR. http://majesticturbo.com/20576.html

This is NOT a street car. I have a daily driver WRX and have absolutely NO intention of making my GLH Turbo into a commuter again.

Lag is not a concern, horsepower is. I don't care if it'll be lazy below 4000-4500 rpm, since I plan on this being a race-only kinda thing. I want a turbo that will maximize my output, so concerns about real-world driveability don't concern me.

Also, since I'm using a TEC3 standlone EFI setup I can employ the "anti-lag" technology all the trick NHRA sport compact dudes use. Something along the lines of "Dump a ton of fuel in, pull timing waaaaay back and spool like a mutha!". Essentially you create a back-fire inside the header collector that spools the turbo instantly. Programmable EFI rawks, eh!

There was a stick-shifted turbo'd modular Mustang running 8.80's in Albuqueruqe a month ago using anti-lag. He'd stage, you'd hear him rev the motor with a few pop-pops and the turbo started bellowing while hed rev in neutral.

So since I'm not looking for the "It won't be streetable" answer to my question: What compressor would work well for 400 hp at a 3.0 pressure ratio? Or since I've got some technology on my side, is there an even bigger turbo that will give me my 400 hp at a lower PR?

-Dana

[theskeptic]

Dang, I sound lik a jerk! That was not my intention, sorry!

I really appreciate any suggestions, but I didn't lay out my plans well enough.

I'm building a '85 GLH Turbo for racing and want to make obscene horsepower. Here's my setup so far:

FM built 2.2 short block
Mike Bachman-prepped G head
2-piece ported/matched
FM TBI -> Turbo header kit
60-1 T04B, Stage III .63 turbine hybrid
Spearco #221 FMIC
TEC3 standalone EFI with direct fire ignition
A568 with Quaife, RP severe duty axles, Clutch Masters 4-puck

So many things to list, but you get the idea.

I'm looking for a wicked turbo that will give me an overabundance of power without the concern of real-world driveability.

Thanks,

Dana

[4sfed4]

Quote:

Originally posted by theskeptic This is NOT a street car. I have a daily driver WRX and have absolutely NO intention of making my GLH Turbo into a commuter again. Lag is not a concern, horsepower is. I don't care if it'll be lazy below 4000-4500 rpm, since I plan on this being a race-only kinda thing. I want a turbo that will maximize my output, so concerns about real-world driveability don't concern me.

Well that makes a world of difference....usually!

Quote:

So since I'm not looking for the "It won't be streetable" answer to my question: What compressor would work well for 400 hp at a 3.0 pressure ratio? Or since I've got some technology on my side, is there an even bigger turbo that will give me my 400 hp at a lower PR? -Dana

There are many compressors that will move 400 hp worth of air at less than a 3.0PR (and the TO4E 50 is one of them). The tough question is finding how much pressure your engine will require to be force fed that airflow quantity.

In my opinion, for 400 crank hp, I dont think you really need much more than the TO4E 50. A tried and true 400 hp (about 350 whp) combo would be the TO4E 50 (maybe Super in your case) / Stage 3 / 0.63 turbo.

Can you go larger? Sure! But I dont think you will really see a difference with a 400 hp goal. All youll get is more lag. I am not downplaying 400 hp as its alot for our engines to make. Heck, I blew mine up at 396 whp :big grin:

If you recall some of my posts from a while back, I actually tested a 60-1 / Stage 5 / 0.82 turbo on my car. Basically, all it added was lag. So, even if one doesnt care how much lag there is, why give up spool for no peak power gain in return?

Tere are also some of the new Garrett GT turbos you could try as well. But, they are going to cost quite a bit more.

[4sfed4]

Quote:

Originally posted by theskeptic I'm looking for a wicked turbo that will give me an overabundance of power without the concern of real-world driveability.

I think this will be waaay too much turbo, but you want wicked right???

The Precision Turbo SC61 is one of the current "bad momma" turbos. I know of two guys using it (non Turbo Dodges) and one Turbo Dodge that will be using it shortly. It kicks butt.

Problem is you need ALOT of engine or rpm to really take advantage of it and most TDs dont fit the bill. If you look closely at the map youll see that most all TDs (even 16V ones) will probably surge at some point in the rpm band with this compressor. As I said...its a bad momma!

The attached file is the map for this SC61 turbo. Its actually the Garrett GT35R compressor.

[4sfed4]

Heres the GT35R compressor in action on a 2.0L Nissan.

This same car actually dynoed at a maximum of 539 whp, but I dont have that plot handy.

So, you see that you need to be serious to use this compressor!

http://web.tampabay.rr.com/enthalpy/...455-actual.jpg

Before this compressor, the car ran the ubiquitous TO4E 50 trim and was still laying down around 400 whp.

[theskeptic]

You are awesome, Larry!

The Super 50-trim looks like a fantastic unit. If the 60-1 doesn't perform well, I'll definitely look into the Super 50.

-Dana

[4sfed4]

Quote:

Originally posted by theskeptic You are awesome, Larry!

I wouildnt say that. Ive had 4 turbos on my car so what I couldnt figure out theoretically I was taught by trial and error!

Quote:

The Super 50-trim looks like a fantastic unit. If the 60-1 doesn't perform well, I'll definitely look into the Super 50. -Dana

For roughly 350 whp on our cars, I think the Super 50 is a better unit than the 60-1. The 60-1 isnt really very happy at high PRs and low airflows like our small engines see. It also has to actually spin faster than the TO4E at the airflow/PR's we are likely to see. (However, I will say this about the 60-1....It sounds pretty **** cool when it comes on full boil! My car let out a wicked hiss when that baby came up to speed.)

But, when you outgrow the TO4E series (you can count the TD's on one hand that need more turbo than any of the TO4Es) , the 60-1 is what most guys have been "stuck" with due to turbine shaft sizes. (Most guys want to stay with the T3 turbines and housings. The T3 turbine shafts are fairly small in diameter and, short of fancy welding and machining exercises, generally only mate with T3/TO4B/TO4E compressor wheels.)

However, as I understand it, that will be changing very shortly! This might be another option for you. Turbonetics has announced they will start making the T3 turbine wheels in the big shaft configuration. This is very good news as it now allows the full T series compressor wheels to be mated to a T3 turbine wheel. From what Turbonetics told me, they will first be producing the big shaft T3 wheel only in the Stage 5....maybe the Stage 3 will follow.

The reason it is such good news to be able to mate a T series compressor with a T3 turbine wheel is that wheels like the T61 would be pretty cool compressors for us to use! Check out the map----

http://majesticturbo.com/30423.html

This wheel is happy at very high PRs and also has a very good surge limit. Even at a very high PR=3.0 like you might run, the compressor only requires about 250 hp worth of air to stay to the right of the surge line.

[DakotaKid]

Larry,
I do not see that turbo being any better for high boost applications.

See the pic, I added lines for my car, like the other graph I did.

Now I am not sure how this plays a part in the whole scheme of things. But the efficency would be worse than the 50-Trim I am using. (Like 10% difference)

The only thing I do see is the degree that the surge line moves UP the graph. It appears the 50-Trim would die at any higher boost sooner because of the degree of change, No?

Your Thoughts?


-Bryan

[4sfed4]

Quote:

Originally posted by TrboVan Larry, I do not see that turbo being any better for high boost applications. See the pic, I added lines for my car, like the other graph I did. Now I am not sure how this plays a part in the whole scheme of things. But the efficency would be worse than the 50-Trim I am using. (Like 10% difference)

Well, the numbers I was using were for Dana's goal of 400 hp with a PR=3.0. So, your car will be different!

That being said....I think you have the TO4E Regaulr 50 trim? That wheel at PR=3.6 and roughly 400 hp is off the map, so wed have to extrapolate.

The big thing to look at is the compressor speed! Look how fast the 50 trim is spinning at PR=3.6 and 400 hp! Again, well have to guess since its off the map, but we know its north of 126,000 rpm!

The T61 will only be spinning about 108,000 rpm. That means the turbine only needs to spin 108,000 rpm and that will drop exhaust backpressure big time. (Thus there will be a big power gain.) However, it will also lag more since compressor lag is almost entirely relative to inducer size (according to the "experts"). The T61 uses a 2.400" inducer veruss the 2.122" of the TO4E 50 trim.

For a car like yours (and maybe others as well) the T-58 would probably be better than the T61. Check out the map. For your car, efficiency would be in the low to mid 70% range and shaft speeds would be in the 108,000 range as well. The inducer is 2.300", so the lag should theoretically be less than the T61.

http://majesticturbo.com/30335.html

It does seem that once you start getting into the huge boost pressures and fairly restrictive engines like ours, it gets harder and harder to find an ideal compressor. For an all out drag car with an auto, its a much easier task though :big grin: You can get away with bigger turbos just by changing your torque converter. You cheaters!

[gasketmaster]

Turbos for all out race cars are kinda like torque converters.You can use the maps and calculations to help get you in the ballpark but you really won't know how it's going to work for you until you use it!
Sometimes you just need to drive a stick into the ground to have a point from which to measure.........sorry,that's my Kentucky roots showing themselves again

Doh!!.........Sorry Ken :big grin:

Turbo oulet temperature will help show you when the compressor side is all done and exhaust backpressure will show you when you need to experinent in the area of turbine housings and turbine wheels.

If you are Drag Racing.......keep a log book.Note your turbo outlet temps,boost pressure,exhaust backpressure readings,EGT's,weather conditions,altitude,time slip incremental ET's and MPH's,ect

Will you occasionally go backwards? Only if you are doing your job well