Jeff20B

iTrader: (13)

Comparing a T04B and GT45. Trying to decide which is right for me.

The T04B has a 1.00 divided exhaust housing and a p-trim turbine! Some say this is the right choice. However the compressor wheel is 82mm so it might spool a little slow for me. The GT45 comes with a .84 divided exhaust housing and roughly the same size compressor as the T04B. Faster spool maybe? It's not a p-trim though. But it does have a 4" v-band while the T04B has a 3.25" v-band. Make a difference in spool? Even necessary?

They share very similar specs. I'll give you the sames followed by the differences.

Sames:
4" inlet
2.5" outlet
divided T4 flange
.70 AR compressor

Differences:
T04B
compressor inducer 65.55mm
compressor exducer 82.00mm
turbine inducer 73.01mm (p-trim)
turbine exducer 64.15mm

GT45
compressor inducer 61.40mm
compressor exducer 82.00mm
turbine inducer 73.60mm
turbine exducer 64.50mm

The GT45 has a water cooled CHRA and an anti-surge compressor housing. The T04B does not. The GT45 also looks better made.

Since the GT45 compressor wheel is slightly smaller on the inducer only, would it spool faster? Combined with the .84 exhaust housing, is this the better choice on a nearly stock ported 13B? Well, 74 ported, but that's another thread. It has a bit more total port area than a stock T2/FD.

Both compressor wheels appear to have 6 blades, but the T04B might have an 8 blade wheel (the picture is not very good). Is there an advantage to having 6 or do I want 8 for lower boost applications??

Which turbo will like 14-15 psi? Which will spool faster? Which will let me run without an intercooler at first like during engine break in/saving up for an intercooler/figuring out where the heck to put it? Thanks.

Jeff20B

iTrader: (13)

Ok so maybe those two turbos are too big for me.

Here is a cxracing turbo that might be perfect for my needs.

http://www.cxracing.com/mm5/merchant...ory_Code=TRBT4

One thing that bothers me is the word "mayor" instead of major. Yuck. But check it out.

I hate that they use inches instead of metric so I converted for you guys.

Compressor Wheel
Exducer: 2.32" 58.93mm
Mayor:3.00" 76.19mm

Turbine Wheel
Exducer: 2.07" 52.58mm
Mayor:2.36" 59.93mm

Um, that's not a p-trim, is it?

Havoc

Is this going on a 13B or 20B ?

If 20B both are quite small. But would be super responsive (and restrictive)

Jeff20B

iTrader: (13)

This is for a 13B. Going NA on the beast. I have a T72 that is getting listed for sale (if a moderator would get around to it). Too bad its 102mm comp wheel is large and laggy on a 2 rotor.

Jeff20B

iTrader: (13)

Getting back to the cxracing turbo, Looks like it's a clone of a GT3076R! But it has a T4 divided inlet and a 1.00 ar housing! Also a 3" 4 bolt flange! Perfect for my needs!

My only concerns are about the compressor housing being a .60 ar with a 3" inlet and 2" outlet. I wanted a 4" inlet and 2.5" outlet (.70 ar).

I feel like the turbine is a little small, but I recognize it's basically a GT30 knockoff turbo, and those only had around 60mm major. This one is around 59.94mm. I wanted a p-trim around 73 or 74mm. The stock S5 Hitachi HT-18 is 63.75mm. Will this lead to too much backpressure and heat inside the engine and turbo?

Jeff20B

iTrader: (13)

Now I'm looking at a TD61 or T04E from turblown. They seem to have the features I'm looking for.

I'm kinda leaning towards the TD61 becuase it has a .70 AR compressor housing. Not only does it flow better than a .60 AR, the .70 AR has a 2.5" outlet which is more compatible with the charge pipe I'd like to run.

Now the big question on my mind is which exhaust AR to get? .84 or 1.00?

Elliot at turblown said there isn't much difference in spoolup between .84 and 1.00. The big difference is that the .84 starts to lose efficiency at 6500 while the 1.00 keeps going until 7500.

So then I had to look at my engine specs. Since the engine isn't built yet, I can make changes and adjustments.

I have three complete rotating assemblies.

R5 13B 9.2 CR 3mm and a GSL-SE flywheel (26 pounds)
S4 NA 9.4 CR 2mm and an NA flywheel (24 pounds)
S6 FD 9.0 CR 2mm and an S5 NA flywheel (21 pounds)

If I were using the R5 assembly, I'd get the .84 AR because it's heavier which needs all the help it can get to spin itself up, let alone a turbo, and it's got 3mm apex seals so that's a practical ceiling of 6500rpm. Would you guys agree?

But since I have access to an FD assembly, and a nice fairly light S5 NA flywyheel, that's a 7500 rpm ceiling, especially considering I have more total intake port area than a stock ported FD, as all four of mine are the same size as FD secondaries. 74 spec!


So I'm thinking the 1.00 housing but would like some opinions. Thanks!

sharingan 19

iTrader: (16)

1.0 unless you use the 5-letter assembly.

Jeff20B

iTrader: (13)

Thanks! Any other opinions?

jantore

Jeff what power ranges are you looking at?

A GT45 is quite big on a 13b. Or are you looking for big numbers?

Id look at Garrett GT turbos. Like a GTX something. From GTX35R for quick fast spool and 400-450rwhp easy. Or a GTX4202R for the big 700-800RWHP

Im gonna run a GT4094R for about 500rwhp on a bridge port E85 engine.

JT

Jeff20B

iTrader: (13)

jantore, at first I was looking for 220flywheel HP because that's double a stock REPU's 110HP. But now it can be 300+

That sounds like a good plan, man. But to answer your question, it's not a real GT45. It has a 61mm/82mm cold wheel like a GT35 and a P trim hot wheel in a T4 divided housing like a Turblown TD61. The only thing that makes it a GT45 is a 4" exhaust outlet. Everything else is like a hybrid GT3582.

If I went ahead and got this fake GT45 it may never perform like a real TD61, but it might come close. Thoughts?

Here is a link. http://www.ebay.com/itm/GT45R-1-GT45...item3a6ecc7990

jantore

Now that's a cheap turbo, hmmm realy cheap. 232 USD for it. Hmm china turbo?

For the power you are looking for id go for a small size GT35R with maybe a 0.86/.82? Or a 0.96 housing and get good low end spool. So that it works good from 2500-3000 rpm.

But a GT35R is quite alot more money.

JT

Jeff20B

iTrader: (13)

Yeah it has to be shipped from China, according to the ad. Expensive shipping charge!

Are you sure about recommending a .96 AR exhaust housing? That's undivided right? That is going to take a lot longer to spool than a divided would.

Oh wait you're talking normal GT35R, so T3 undivided then? Not really interested as the hot side is too small, and I don't want a high backpressure hotside as that eventually leads to problems (and can be bad for apex seals springs when the heat travels back through the exhaust ports on shut down and can ruin the temper of the spring steel if an apex happens to park over the port - like running a thermal reactor with no air pump).

I've seen fake GT35s on eBay with a T3 hot side in a .82 AR divided and considered getting one. But anything with a T3 hot side just works out to be too small for me. Then again I'm new to turbos so I don't really know.

Another thing about any T3 that's within my price range is the exhaust outlet is usually 2.5" in either a v-band or a 4 bolt flange. I've already set my sights on 3" or bigger. I've seen lots of T04B p-trim type turbos with a 3.25" v-band, so that could work for me. I'd just have to adapt it down to 3" for my exhaust system.

Speaking of which, if I get this fake GT45, I'd need to do something about its 4" v-band. Hmm... maybe run a 4" downpipe? Too big?

I read somewhere in an old post on this forum that 13Bs love a p-trim. So I looked up what that is just so I can understand what it means. It is a turbine wheel in a "T4 frame" exhaust housing that measures from 73-74mm major and around 64mm minor.

I read elsewhere that a rotary loves a divided housing because it lets the strong exhaust pulses do what they do best ie it spools a turbo faster. Also apparently helps "transient" response, whatever that is (I can guess what it means... but total noob here so I'll let you tell me).

I also want to go with a T4 frame size on a 13B because the T3 volute is way too small. Now I don't know if that is in regards to divided vs undivided, or in other words whether an undivided T3 volute is ok on a rotary as long as the AR is big enough, but stay away from a divided T3 as the two volutes are tiny? Don't really know so I chose to focus on divided T4 housings so it's guaranteed to be big enough if I go with the T4 frame size.

You also want to look for a 1.00 AR because .84 will limit you above 6500 -- at first I liked what I read about others using a .84, and felt it would be best for a truck that needs low end torque (and spool!) but Elliot at Turblown said the actual lag time difference is pretty small, like 400rpm (that's like nothin'!). He said the biggest difference going from .84 to 1.00 is at higher RPM as mentioned above. He also recommended me a T04E because it spools another 300rpm lower. Hmm, a total of 700rpm sooner spool is nothing to shake a stick at. But I also have a budget to consider here, and haven't found a decent looking T04E with a divided p-trim on eBay yet.

Why is it they always have several T3/T4 hybrids listed which have a T3 hot side and a T04B cold side? Man I'd prefer the other way around with a T04B (T4) hot side and a T04E cold side lol!

Jeff20B

iTrader: (13)

I kinda like what Zero R said here: https://www.rx7club.com/showpost.php...4&postcount=15
Just wondering if this pertains to me going .84 if I have a 3" or greater discharge?

Whatever I do, I'm not interested in a turbo with a 2.5" or smaller outlet or "discharge".

just startn

iTrader: (33)

You describe something like this.
https://www.rx7club.com/single-turbo-rx-7s-23/need-opinions-gt37-please-990739/
http://www.ebay.com/itm/Precision-PT...cd112d&vxp=mtr

Jeff20B

iTrader: (13)

Thanks for the link! But it's not quite like this turbo. That one is bigger than this fake GT45 "thing".

As for where knonfs mentions .84 and more or less recommends it, turns out I had remembered what Elliot said incorrectly. Here is what he said.I thought he meant the turbo BEGINS spooling 300 rpm sooner for .84, and 400rpm sooner for the To4E. That's where my 700 rpm figure came from. Glad I caught it my mistake.

So now it seems it doesn't really matter which housing I get for low end spool. The only real difference is at high RPM. I'm not really concerned with WHEN it reaches full boost. What I'm interested in is how soon boost begins to build. So it seems I can choose any combo.

I suspect there is another difference, not touched on in the PM, that Howard Coleman mentions from time to time is how much heat the turbo will add to the engine due to pressure ratios or backpressure or whatever it's called that builds up inside the exhaust manifold. So I'm thinking because it's a truck and will receive some level of porting, it should probably get a 1.00 housing. This is to reduce heat and backpressure for a longer survice life and future compatability with other engines and more porting options. Then again it IS a truck and would like to reach max boost as soon as possible... so .84 right?

I'll need to read up more on the subject of course. If anyone has anything to add, please do. Thanks!

jantore

You can get the GT3582R with a T4 housing, but it's a 1.06 housing. Not sure what the spool difrence would be on that.

I have had the T04E and was quite happy with it. About 400rwhp at 1.3bar of boost. But spools quite slower then a GT turbo. Ballbearing is what you want for low end spool.

But get what your gutt tells you and what your budget allows

JT

FD_FTW

Gt35R!!!

Jeff20B

iTrader: (13)

Thanks jantore. Ball bearing would be nice but going journal.

I just worked out the trim of that strange turbo listed above with the GT35 wheel and a p-trim.

compressor
56 trim

turbine
76 trim (basically p-trim)

Do I want a 56 trim compressor wheel?

XLR8

iTrader: (52)

300+??

TO4E
TO4S

I would keep the A/R between .84 and 1.16. Adjust it on the low side for better threshold.

http://www.atpturbo.com/mm5/merchant...egory_Code=TBN

http://www.atpturbo.com/mm5/merchant...egory_Code=TBN

The 60-1 will make more overall but both are going to depend on boost level. The more boost you run, the faster it will spool. If you are planning AI or water then I would just pick up a T04E. You can wring it out to 20+psi and get 400hp and it would be very snappy in spool. The T04S will make high 400's at the same boost.

Don't dick with junk turbo's. IF it's an absolute budget build, then pick up a used Garrett.

Jeff20B

iTrader: (13)

I'm throwing a new(used) Garret in the other rotary baja. It's T04E 57 trim with a p-trim hot side and a 1.32 housing. We'll use it but look for a .84 in the mean time.

That is for the baja. For the truck, looking to run 15psi on pump. Don't want aux injection. What are my options? Actually 5-6psi up to 15psi.

I have a new 46mm "precision turbo" wastegate in the box. Big enough?

Turblown

iTrader: (12)

Why run an oil cooled only To4S for $100 less than our TD61?( which is water cooled..)

sharingan 19

iTrader: (16)

The world will never know...

Jeff20B

iTrader: (13)

Just picked up some 3/8" tubing to make a new fuel send line.

Jeff20B

iTrader: (13)

Thinking I'm gonna go with a .84 hotside and a 3.5" downpipe. I don't need much past 6500. I could use all the low end spool I can get. Thoughts?

Rotospeed

iTrader: (8)

sounds like you are looking for something like thishttp://www.godspeedproject.com/shop/...oducts_id=1509

or maby this
http://www.godspeedproject.com/shop/...oducts_id=1065

this is also what im lookin at for my 1/2 bridge 12a if i upgrade the turbo