garrett gt35r .63 ar too small?

[lowvr 0]

looking at upgrading to a gt35r.

engine/gearbox spec:

forged je pistons (8:5:1)

schimmel h beam con rods

arp hardware throughout

charge cooler set up

02m 6spd conversion

I want the power to come in early as possible and and progressively as possible (hence i will be using stand alone management with variable in gear boos control) I want to turn up the boost to the limits of the engine and effeciancy of the turbo .... I think 22+ psi will be a good initial target

but i wanted the opinion of anyone who has run a genuine garrett gt35r....

is a .63 a/r going to be too small/restrictive as i hate when the power dies off as i chase the redline ... i personally cant see it being a problem as the gt35 is big-ish turbo with big-ish wheels

[Jonrandom 2]

Your going to see good power from it it just depends on your goals?

Im in the same boat as you mate have bought a gt35, cleared me out for now! will be getting the rest of the bits like you have hopefully soon.

Would like to know some of the info as well.

How come your going to go stand alone? Have been told the the standard ecu can be mapped for a turbo no problem?

Also was thinking about getting a charge cooler look good and they seem to be the one in the US but as well as the tank do you need to have a cooler/radiator as well for the water, just seems more to go wrong and not really better gains from a intercooler?

Im not sure myself mate just some of the bits ive read and thought would like to the answers as well mate

[lowvr 0]

power goals i would like to keep under 550lb torque and dont have any plans to go above that. my rationale is the 02m gearbox becomes temperamental after that

If i need more power in the future i will add nitrous to the build.

im going stand alone because ive had this car since 1997 and have no plans on selling it...it will always be a "build"

i plan on future tuning and adding more options such as antilag

i will also be using variable in gear boost control hence i dont see the point on flashing the stock ecu to only add an apexi or something along those lines.

Also have no limit to where i will stop adding boost ...it will either be when i think the car is too fast for me or something blows up ...which ever happens first.

i also will be doing a wire tuck at the same time and i think the sand alone makes it easier ...no airmass needed either so will just probably put gauze over the turbo.

chargecoolers do require a rad and tank but they dont need to be massive...tanks can actually be quite small (mine is). MOre complex than an air/air cooler but not exactly rocket science. Simple steps will make sure it runs right

read through this for more information:

http://www.chargecooler.co.uk/index.php?main_page=page_3

[MaidenVR6 26]

In 2007 i had a Garrett T04S T3. 0,63 It was maxed out at 5500 rpm. Made full boost at 3200rpm and broke two gearboxes incl a SQS 02A. Its NOT what ypu want. In 2009 I got a GT35R T3 1.06 Max boost at 3700rpm and from there it goes on until it hits 7200 revlimiter hard. I still have that turbo and it operates from15-30 psi when it maxes out. Solid, reliable and perfect for a 15+psi engine. Forget 0.63 and 0.81 Get the 1.06 and be happy togheter with your gearbox that needs a LSD diff.

[matty.vrt 120]

550lb maybe the limit with the full strain and pure grip of a 4wd system but if your running 2wd the reality is you can run much,much more. As for the GT3582R the .63 hot side is far too small more suited to say a 2 litre evo. I run the .82 which starts making boost a 2800 and makes full boost about 3500 but always wish i went for the 1.06 like Maiden as a small hot side restricts higher in the rev rage raising EGT's especially running 30psi

[matty.vrt 120]

On the management side i run 630cc C2 tune like Maiden and love it if you go stand alone go expensive eg... DTA, AEM or similar I had a emerald was poo i mean dog poo lots of issues.

[lowvr 0]

i appreciate the above ...both maiden and matty

do you not think the 1.06 will be a bit laggy? ...or is this really not an issue? ....i appreciate the vr6 being nearly 3l (mine will be a true 2.8 as i wanted to keep the integrity of the block) but it doesn't have the best head flow and with the lowered compression ratio to (8:5:1) will its not be a slug pre-boost.

from the info above what we can guestimate for the vr6 gt35r :

0.63 - onset of boost? ...full boost (psi?) 3200rpm ...will max out around 5500rpm

0.82 onset of boost 2800 ...full boost (?psi) 3500rpm

1.06 onset of boost? .....full boost(?psi) 3700rpm ..will keep going on past 7200rpm

i would also like to mention at this point that:

i plan on running a 3.5" downpipe and that will merge into a 3" system with no boxes

and i may move this engine into my 4wd haldex shell eventually ....is the 1.06 still going to be the best choice for 4wd power?

from everything discussed above i am heavily swaying to the 1.06 now as all my calculations on this turbo sizing have been based on theory, but the end users performance means more to me than just numbers ...i am not concerned about headline figures, i just want a fun car to drive

i have one other query....what size oil restrict or is suited for the this turbo/engine combo?

[Jonrandom 2]

Some good info cheers. Still cant decide between charge cooler or a intercooler, guess will depend on space in the bay and the easiest to sort out, will see when fitting the engine. Ive got the later 24v so I guess better ecu for management.

As said I agree and reckon you should go for the 1.06, like you say its nearly a 3l and with a proper manifold, downpipe and exhaust can reduce the lag. Ive got the GTX3582r it ran 700bhp on a evo and can produce more. Dont know what the lag was I'm sure a fair bit on the evo but on a 3l with the right intake, manifolds, down pipe and exhaust the lag can be massively reduced.

[matty.vrt 120]

Trust me there's no lag with the .82 and makes 24 psi at 3500 and 30 at 3700 and holds it to the redline. I think .63 would choke it up like a ko3 on a 1.8t,

[lowvr 0]

I'm convinced

First thing Tuesday morning I will order that 1.06 gt35r

What size oil restricter do I need with it?

Matty which emerald ecu did you use on your car what problems did you encounter?

[matty.vrt 120]

Had loads of problems with mapping it and all of a sudden one day it would run crap and I would have to alter the map, could never get cold start right, used to just cut out sometimes when it got hot. It was the k3. Some could argue that all my problems were down to my lack of knowledge on standalones and trust me at times it had me doubting myself, I like the c2 chip the best runs like stock till 3000 then all hell brakes lose I've ran 7psi 300bhp 11psi 360bhp and 24psi 449bhp and that was on a 170000 engine with un-equal compression ranging between 6-8bar it's amazing.

[lowvr 0]

did you map it yourself matty or did you have someone map it for you?

[matty.vrt 120]

Ihad john sleath map it he was amazingly talented he managed to get 360bhp from 11psi

[lowvr 0]

quick update

order the turbo still waiting on it to turn up ...it should have by now but im sure it will ( i hope)

also been thinking about oversize valves on the head with new spring and retainers

i don't want to spend unnecessarily but these are my concerns:

the power output i hope to achieve with this gt35r 1.06 on 630cc tune is going to subject my head to a much higher range of temperatures... i can see in theory the advantage of new valves made from something more suited to withstand this heat

if building with new valves and with the size of this turbo it only makes sense to oversize aswel ...i figure 41mm inlet and 36mm exhuast would be a good step up ....?

...what gains can i expect to see from this and at what rev range?

also if going down this route for larger valves how essential is titanium retain and new valves?

i also see this effectively giving me an increased rev range ...but what can i safely raise my rev limit to? ...i want to know i have built a reliable engine even at this high output

[matty.vrt 120]

Standard valves cope fine with the heat and they have been proven to work well over the years on many turbo builds. I have Firera over sized valves and titanium retainers, why you ask? No particular reason other than when spending the money on good quality valves why skimp on retainers, i also run HD valve springs as this is advised with high lift cams. sp turbo sell a kit so you can diy BVH rather than pay the shipping on a built head. I'm finding since i have fitted the sp turbo BVH im making 5psi between 2500-3000 where as i was only making 1 maybe 2 before.

[lowvr 0]

i just noticed my typo above, the paragraph was mean to say

if going down this route for larger valves how essential is titanium retainer and new valve springs?

but you already answered this ...thanx for the information matty.

I guess i did know the answer but was just trying to see if the money spend on the retainers ans spring was better spent somewhere else...but i cant see that being the case.

with the combo above ...larger valves + hd springs + titanium retainers so you have any theories on what i can safely raise my rev limit to

[matty.vrt 120]

Think the old 12v is about done at 7500 even with this setup i would make that your limit revs kill engines, if you require more power up the boost.

[MaidenVR6 26]

Standard head will work just fine with the 35R.

[matty.vrt 120]

Standard head will work just fine with the 35R.

Very true i ran mine with standard head for about 3 years, but with BVH it is soo soo soo much better both on and off boost its like a different car.

[lowvr 0]

Advice taken on board. I got a blistering deal on some 36mm and 41mm valves so BVH is happening. Will probably order the rest directly from stateside now

If at a later stage I add nitrous to the build plans above is there anything that is worthwhile doing to the internals at this stage to help prepare.

I'm trying to preplan to avoid pulling it apart for no reason as I want to add nitrous as soon as I can get it running at its optimum.

Also I was originally going to use Siemens deka 630cc I injectors as I already happen to have 4 but researching current advances in before technology genesis II 630cc seem to be a better part in everyway. Price difference is $120 more for genesis for set of 6...any experience using these?

This thread is proving to b very usefull can't thank you enough for the pointers so far

[matty.vrt 120]

I use Siemens 630cc and have no issues I cant see the point in paying more, maybe on 4cyl 16v/20v layout spray pattern and other things become more important but due to the layout of the vr6 head, with 3 cylinders at the back it is not really worth it. if you are making the investment into forged pistons you can get an optional top coat that is good for nitrous applications.

[matty.vrt 120]

http://s1325.photobucket.com/user/mattyvrt/media/vr6%20turbo%20build/80886374-E0E9-4C6D-A46C-9C6BEDF17F6F-1434-0000010075139EB5_zps21d95422.jpg.html?sort=9&o=35

[craggsy 91]

Just for reference I have genesis 550cc in mine

[MaidenVR6 26]

Buy two 630 Deka's and be happy. They are good injectors. Had mine since 2009 and been running up to 30psi. Runs very good.

[lowvr 0]

I sold my set of four 630cc and will order a full flow matched set of 6 Siemens dekas

When I ordered my low comp forged je pistons I should have ideally had the top coating added then. Any uk recommendations to coat the pistons?

I know of a few that do the job but no first hand experience.