T25flanged GT3071R from ATP turbo

[Gladius]

Looks like atpturbo released a t25 flanged version of the popular GT3071R turbo. http://www.atpturbo.com/

I wonder if this would be feasible for the stock rwd bottom-mount manifold? I'm sure some custom oil lines will be needed, but hey ya never know.

Sr20chris, msaskin? Any insights?

[msaskin]

Sr20chris, msaskin? Any insights?

Wow...I'm being asked for by name...does that make me a guru or something

It will definitely fit the stock bottom mount manifold if they're saying it's the same physical size as a GT28RS/GT2871R. Hell, I've got my GT25/40 stuffed underneath the stock manifold...had to take off the corner of the motor mount and a big chunk out of the motor mount bracket to the block, but it fits alright

I'm not too familar with the GT3017, so whenever ATP's site decides to work again I'll take a look at it and give me take (which is little more than a slightly educated guess) on how it will work for the motor

I would say that more power while sticking with a bottom mount is cool. Also, at least it doesn't have the ridiculous T04(S?) cover that the GT25/40R has...the stupid 4" inlet is really f**king ridiculous.

EDIT: as for oil lines, i'd imagine you'd be able to use the same aftermarket lines that you use for a GT25/40...the taka motorsports ones are nice. Alternately, you can get the lines from ATP for a bit less cash, they're kinda long, but I will say that my taka coolant feed line is a real tight fit around the compressor cover on a GT25, I would love a bit longer line for more slack. Another thing is the taka lines don't come with an oil restrictor so you'll have to get a .032" or so restrictor (ATP sells one for $12 that threads into the block for the oil feed) otherwise you'll do nothing but blast oil past the seals on the turbo (ask me how I know :-x)

~matt

[f150intally]

Matt, how do people connect the coolant line from the back of the block to the stainless braided line? I'm talking about the hard line coming around the back that connects to the rubber line? How do people connect this up usually?

[Gladius]

Haha, you seem to know a few things, plus you have an gt25r on a bottom mount like me, so I figured you might have a good idea.

I know the site is kinda limited right now, but the compressor and turbine maps links work for the 3071.

I agree that the 4" inlet is rediculous, but the pic from the main page it seems you can get the compressor housing in 2.something" or 4". If it is 4", then i would just get that one since my intake pipe is already set up for that size.

I wonder what the spool on that thing would be like. I hope its better than this damn 25r.

As for oil lines, I'm using stock ones.. they're just bent a little. Would the oil inlet on the turbo be in the same place as the 25r? I might be able to get away with reusing the stockers.

[f150intally]

How would it be better than the 25r? its using the same exhaust side and has a bigger compressor section.

[Gladius]

The 3071 uses the same turbine housing, but different a/r and turbine trim. It'll act as a totally different turbo than the 25r, more linear instead of peaky. Plus the wheels arent mismatched like the 25r.

[msaskin]

To address things one at a time:

The 25R wheels are mismatched, but for a reason. the NS111 wheel is relatively lightweight for it's size. The mismatch in size goes against traditional turbo building "rules", but it's exactly what garrett intended the GT series of turbos to be.

For coolant line: I'm running the taka motorsports lines. The coolant return is an AN fitting off the turbo, the line then runs behind the head and at the end of the line is what appears to be an AN fitting but really has a small hose clamp (that you tighten with a flat head screwdriver) at the end, so you just slip it over the small hardpipe coming off the coolant pipe that runs under the intake manifold then tighten it down. Make sense???

Also, I wouldn't consider the 25R to be that peaky, it's real linear once you're above 3500rpm or so

Admittedly the 3017 should have a wee bit better bottom end (or at least faster spool). When I have some free time i'll take a close look at the flow maps and try to get a better idea for it.

~matt

[Gladius]

I went ahead and plotted some points on the compressor map provided by atpturbo for the 3071r. Here's the link for map... http://www.atpturbo.com/root/maps/gt3071r.htm

Here are my assumtions.

- intercooler pressure drop, 1.5 psi-air filter pressure drop, .75 psi-atmospheric pressure, 14.7 psi-post-intercooler temp of 590 Rankin or 130 farenheight-displacement of 1998cc or 122ci-90% Volumetric Efficency throughout 4k - 7k rpm range... i know its not but hey, life is short- I corrected the airflow for the compressor map

I plotted 9psi, 12, 15, 17 and 20 psi, in rpm increments of 4000, 5000, 6000, and 7000rpm for each psi.

i.e. for 9 psi at 4000, 5000, 6000, and 7000 then 12psi at 4000, 5000, 6000, and 7000 and so and so forth for 15, 17, and 20psi.

Now, the efficiencies..

The turbo stayed in the efficiency range of 72% to 75% throughout all said rpm's (4k-7k)and pressure ratio's(1.7-2.5). Guesstimating a 7psi from 3k, 4k, and 5k rpm's the average efficency is in the mid 60%'s.

My guess is that this turbo will make a couple psi at 3000rpms and build and stay very effeicent from there.

Tomorrow I am going to post up a pic with the plots on the map give ya'll an idea.

[msaskin]

You did exactly what I was planning on doing tomorrow sitting on an airplane

Looks like a great match for the engine...more power potential than a 25R with the same if not better low end. Another thing to consider is the much wider choice of turbine A/R's (.63 - 1.03)

Interesting indeed.....

~matt

[Gladius]

I totally agree. I think this is going to be a great turbo for us SR's. I think we would benefit the most from the .82 a/r turbine. I will be purchasing this turbo when it is fully released. I guess I'll get to be the test fit guinea pig on a bottom mount mani.

[f150intally]

believe it or not, most tuners use a VE of 1.0 on our motors when building compressor plots. Scott from Secret Services told me that you can actually have a VE higher than 1.0. So you .90 is not off base at all.

here is a handy spreadsheet that uses the formulas provide by garrett to calculate mass flow of the engine. Hope this helps you.

[msaskin]

Scott from Secret Services told me that you can actually have a VE higher than 1.0. So you .90 is not off base at all.

Did scott give an explanation why? I just can't seem to figure out the physics behind it. Of course I still believe it since I've yet to see bad info come from scott avoy, but still, I'd like to understand why

~matt

[f150intally]

i can't remember the explanation. He also helped me revise the spreadsheet with the latest formulas from garrett. he deserves partial credit for the Compressor Math Spreadsheet.

[Gladius]

That all great info F150, thanks. I just assumed the 90% VE througout the rpm range for times sake.

Here's the points I plotted.

Modified by Gladius at 11:18 AM 9/27/2004

If anyone can host, I can get a bigger image up thats easier to see. Stoopid Imagestation.

Modified by Gladius at 11:22 AM 9/27/2004
Modified by Gladius at 2:52 PM 9/27/2004

[score]

I can host, shoot me an email with the full size pic attacthed. [email protected]

[f150intally]

gladius, nice work. throw one on there with 26psi and email it to me at [email protected]. I can host it for you.

[score]

Non uncompressed image attatched:

Looks like fun.