Well, I am stuck on purchasing the TO4R with a 1.00 AR hot side P trim. ATP suggested this turbo....

Garrett GT4088 Journal Bearing Special
Code: GRT-TBO-035


Garrett GT4088 Journal Bearing. Compressor housing is slip on 4" inlet with anti-surge ported shroud and compressor outlet is 2.5" slip-on. ATP Special Exhaust housing with divided 1.06 T04 Flange with standard 3" V-Band machined into it for easy downpipe compatibility and plug and play replacement for older large frame T-series turbos. Largest trim available in GT40 family capable of making a healthy 700+ HP setup.


Turbine
-Wheel: 77mm 84 trim
-Maps: Not Available

Compressor
-Wheel: 88mm 54 trim
-Maps: Not Available




My target for the TO4R was in the 500 BHP.... Purpose for the setup for street/strip use....I do want a drivable car, with some compromise... and yes i do have the supporting mods like doweling porting of oil pump and pass...etc etc.

Now how will this turbo compare with the to4, with regards spool, flow, pressure ratio etc?

The inducer seems to be much bigger than the to4. From the dyno sheets and word of mouth i was led to believe that the to4R is very streetable, will reach the 15psi round 3500rpm with the right porting. Will this compare? Any body running this turbo?
I will use the Tial 46mm WG for the set up....

Feed back will be appreciated. Sorry but I have no flow maps for this turbo or any maps what so ever.

This is the link to ATP:
http://www.atpturbo.com/Merchant2/me...ory_Code=GTNBB

Thanks all...

George

 

Here's a compressor map.

http://www.turbobygarrett.com/turbob...8_703457_2.htm

 

it seems to me from those charts....this turbo has nothing to do with the to4r specs. it will boost like a t78 i figure roung 4500-4800rpm.....

right?

 

Ps.... it has no wet section and comes with a divided flange and smallest ar of 1.06...

guys, some feed back please....

What am i lookin at regards rwhp on 15psi? (extended street port and 3mm seals)

Thanks

George

 

i'm wanting feed back aswell. i'm stuck on a turbo.

 

bump^^^^

 

This turbo should flow about the same as a T04R, the compressor inducer is a little smaller, but its exducer is 4mm larger, which should help boost faster by itself, but on the other hand its turbine is a little larger than a P trim on a T04R, which might make it boost a little slower by itself, so response-wise both should be a death match. They are both 70lb/min rated, too, so it might be a "new tech, old tech" choice in there only. And they are both priced around the same. Hard choice, only experience will tell... Its turbine inlet is a perfect match to an SSA manifold, tough.

 

hmm thanks, makes sense. So, since the GT040 is not a ball bearing turbo and does NOT have a wet section, would then the To4r be the better option for street strip use?

I am worried that the GT will have heat issues, since it is not water cooled.....

what would you do had it been for you?

Thanks

George

 

the t04r is a much more proven turbo. i have seen some numbers from the gt40's and i am not too impressed. i havent seen many gt40's over 400whp at 15 psi, now as for the t04r it will get around 420-430whp on 15psi (depending on ports and all) and flow over 500whp on high boost. here are some dyno sheets you might want to check out.

also heres a link to the gt40's dyno.

https://www.rx7club.com/showthread.p...ight=rx6+gt40r

 

I'll give the nod on the T04R over the GT4088: as it uses a common P trim hotside, you can just switch to so many other available A/R covers if your initial choice doesn't suit your response needs. Also, its replacement parts are basically universal.

 

just a few ideas for you...

firstly, i don't recommend any dry turbo for the rotary. i digitally log EGTs on both of my rotors. if you don't run water/alcohol injection you will be making at least 1750 degrees into the turbine. piston engines make 1325 degrees when properly tuned. you need all the help you can get as far as cooling. yes, i know a few mid hp turbos seem to run ok dry but you don't want to roll the dice on a 400+ hp setup.

as to comparing turbos sizewise...

i solve for the area of the major and minor wheels and then use the average...

looking at the to4r and the gt4088...

to4r
compressor area is 6.99 sq inches, o k, call it 7.0
turbine is 5.894 sq inches

gt4088
compressor is 7.247 sq inches
turbine is 6.38 sq inches

so you see the gt4088 is 3.5% larger on compressor and 8.3% bigger on the hotside.

cold to hot ratio is 1.18 for the to4r and 1.13 for the gt4088.

as to flow...

i haven't found a published rate for the to4r other than ray hall's site which uses 63 lb/min. while i think highly of the site i doubt the flow based on the hp levels achieved by the to4r.

my guess is since the cold wheel area is 96.5% of the gt4088 the wheel flows 96.5% of the 72 lbs/min of the gt4088 or 70 lbs.

based on the above flow rates using the following formulas here's what you can expect to make in Rotary rear wheel hp...

to4r

70 lbs/minute X 14.471 = 1013 CFM/ 1.92 = 527 Maximum Rotary rear wheel hp.

gt4088

72 lbs/min X 14.471 = 1042 CFM/ 1.92 = 543 Maximum Rotary rear wheel hp.

 

Well, it seems after all, that comparing apples to apples, the to4r is the better deal with regards to reliabilty and availability.I wasnt very impressed with the GT4082 that's on the other thread.... i would have a =expected better numbers from a turbo that is said to flow some 900cfm...

Well quoting turboby garrett, the to4r flows 75lbs/min. I cant prove this claim, but at the expense of 15hp, i have the availabilty of a 'wet' turbo. yes my target is within the 500 mark. so as such, from the dyno charts, equipment reliabilty etc....the to4 is your recommendation.

Thank you to all for the very informative posts. I will stick with the to4r....pity it does not come with an anti surge housing.... HKS sell the to4Z housings, but i doubt that they actually are competable.

Yes the Turbine intermixing is also an asset. thanks for pointing that out.

so, based on your info gentlemen, i will go for the to4r.

Thanks to all!!!!!!

George

PS...Happy Christmass to all of you!
G

 

i prematurely hit the send button... continuing on..

notice i solve for Rotary hp.

when you read published hp targets for various turbos keep in mind these are generally for piston engines. the rotary is less efficient in converting airflow to hp.

a general rule for piston hp is to multiply airflow lbs/minute by 10 to get hp. in order to get Rotary hp you then divide by 1.3

using the above flow #s.

to4r 70 lbs/min X 10 = 700 piston hp/1.3 = 538 Rotary rwhp

gt4088 72 lbs/min X 10 = 720 piston hp/ 1.3 = 554 Rotary rwhp

these are MAXIMUM #s. you need everything optimised.... support systems, tuning etc. you will not want to run this tune on the street... one bad tank of gas and, well you know the storyline.

perhaps a more real world method of setting expectations would be to look at the compressor map flow at one bar ( 14.5 psi), and say, 17 psi... the general limit on 93 octane pump gas.

since i don't have a to4r compressor map let's use the gt4088...

at 14.5 psi... 58 lbs/min or 840 cfm/ 1.92 = 437 rotary rwhp
at 17 psi... 64 lbs/minute or 926 = = 482 rrwhp.

a final non hardware comment is that it will be important to find a turbo vendor that will support you after the sale. the best way to figure this out is to talk w people who have already been down that road.

good luck,

howard coleman

 

Thanks Howard.

Very Knowlegable! Thanks for the info. I will stick to the To4. Yes, I fully agree, porting, tuning, supporting mods, FUEL and all are a must. I dont see a rotary doing 700 bhP on a to4 or gt 40.....

Reliability and aftermarket issues too are decisive factors!!!!

Thanks all!!

George

 

Is the water jacket on the T04R standard fare or an option?

 

No its an option, but the all up price is the same as a GT40.
i gather its some $75 extra.... but dont quote me!!
I have been quoted $850 for to4r with these specs:

Compressor TO4R/T4
T4 turbine & foot print divided Hotside
66.5mm inducer
P-Trim
Exhaust A/R 1.00
Intake A/R 0.7
V Band Exhaust 3"
4" intake with 2.5" air outlet
Wet Section
360 Bearing.

 

i can sell the TO4R for $825. pm for more info.

 

If with the above specs, am interested^^^^^

pm sent

 

Sorry to get off topic but...where did you read that at Howard?

Maybe they were refering to NA piston motors? Or maybe they were refering to EGT after the turbine wheel?

Well tuned turbo piston motors normally run 1490-1650F when measured 4" off of the head (which is common practice). 1490F being a low boost/advanced timing setup and 1650F pushing things a little. A really aggressive setup pushed hard on quality fuel with the timing pulled way back might make max power at 1700-1720F.

 

i was referring to NA piston engines.... 1325.

my Roger Mandeville & Daryl Drummond 12 A Bridgeport SCCA GT3 (NA) motors all tuned on an engine dyno made max hp at 1750

howard coleman

 

btw, i will sell the "wet" center for the same price. Generally the only customers that ever request the wet are the road race guys that more often use the smaller turbines which build a little more heat and, that are loaded for much longer durations.

 

How streetable to you guys think this turbo is?? I have been checking into it and am looking to get one myself.

I need a divided housing for my manafold, and i was wondering if i could get some opinions on what a/r to go with if i were to go with this setup??

 

yeh, intention is for road raced and minor strip work......pm sent with e mail..... email me


Well, it should boost 15psi by 3400-3800. as i drove the turbo, and i compare boosting like to a non sequencial setup...just load more of kick!!

I am going forthis setup, so its streetable, but i can have fun at the strip...you should be able to tune..to over 400 rwhp....

DR...email me!!

George

 

anybody here actually already using a GT4088?

 

^^^^bump....anyone?