Holy turbo lag

[boost addict]

So Ive been trying to figure out why my setup lags so bad. Its a 3071r with a t25 turbine housing on an sr. Its bb and not blown. Its internally gated and the flapper isnt leaking or stuck open. Could it be the turbine housing inlet? Me nor the guys at ill garage have been able to figure it out, although they havent looked into it. Only tuned it and gave suggestions. Any ideas?
yuckk
http://i42.tinypic.com/10nyu6c.jpg

[Croustibat]

More details please.

A/R and trim of the turbo ? boost pressure ?
real garrett or an ebay copy ?
Maf ? Injectors ? Fuel ? cams ?
Sure about the CAS / timing setting ?

It sure lags badly ...

[boost addict]

Its an atp turbo so it has their housings but a garret center housing. .86 turbine. I running it at 22psi with bc 264's, 93 pump gas, 850cc sards, and a z32 maf. Armondo at ill garage played with timing but had no diference in spool. Hes the turbo GT3071R-WG Dual BB, 86AR, 90 Trim Turbine, Ball Bearing Turbo : atpturbo.com (http://www.atpturbo.com/mm5/merchant.mvc?Screen=PROD&Store_Code=tp&Product_Code=GRT-TBO-026&Category_Code=GRT)

[rcdad123]

i think .86 is kinda big. try a smaller turbine a/r. or add timing at lower boost pressures. add one degree at a time till your satisfied.

[s15specR]

I would have went with a smaller AR like a 63 or 64, not sure it's available on that tuebo though.

[boost addict]

they have a .64 ar 84 trim model but im am currently emailing back and forth with atp about the same issue and one of the techs said it wouldnt spool that much faster. he said this turbo is spooling like a 42r

[boost addict]

The tech also said that my cam timing could be off a tooth of so. But I thought I heard the motors barely run even off by like one?

[S14DB]

It uses a smaller turbine wheel then the T3 3071. It's modded to fit the housing not for performance. It's not an ideal setup.

T3 3071 Turbine Wheel: 60mm w/ 84 trim
3071 WG Turbine Wheel: 56.5mm w/ 90 trim

There are some threads around about the 3071WG's problems.

[codyace]

Poor housing choices and crappy wheel selection will kill ya. A Good running 2871r would make more average HP and TRQ by far.

I'd sell yoursetup and reduce bac kto a 2871 or just step up to a true 3071 and make some HP.

[boost addict]

Yea I've been thinking about selling it and going t3/top mount all thy jazz. Ill probably go with a precision turbo since they're like 20 min away and cause I have friends that get deals

[Croustibat]

some of the problems are here:
bc 264's, 93 pump gas

long duration cam gives more spool time too. and 93 pump gas ? Seriously ? You want power but you cheap out on gas ? Use high octane and a map made for that. Also, sell those cams if you want low spool time. These have way too much overlap. You added 24° of IN and EX opening, no wonder you get such a bad spool. That set of cam was developped with SR20DE in mind (you can use SR20DE cams in SR20DET), there is no way a turbo setup can benefit from that. Unless you plan on getting a usable powerband of 6000-8500rpm.

Your setup shouts "I WANT TO PRODUCE A LOT OF POWER AT HIGH RPMs" . That is what cams and big turbos are all about. You cant reach them with 93 pump gas, you will have to pull timing long before it reaches the power band.

Your timing can be off a couple of teeth without having the engine run completely bad. you can usually spot that by looking at the CAS, if it is fully set to the left or the right to be at 15° BTDC at idle, your timing chain (or belt on a CA) it out at least 1 tooth. If it looks like it is at the center then its ok. It just lags a bit and lacks power when it happens, but nothing like 50hp. A lot of CAs and SRs out there suffer from that, it is very easy to get a tooth out on these engines when tightening the tensionners (although it is much more common on CAs than SRs), even professionals make that mistake.

I think you need to refine your goals here.
-If you want high power at high rpm, try sourcing 256° IN cam. It can work with 264° EX cam quite nicely. Then high octane fuel and a lot of work on the head awaits you (it does not like high rpms) . That should give you a better spool time. finally up the boost to 25-28psi, and get higher flowing injectors. Even bigger if you go e85. This should put you near 500hp mark.

-If you want the same power level but sooner, install oem cams back, use a GT2871r and high octane gas. With a proper mapping.


Either way your engine begs for high octane fuel, so use it. You are currently getting the power level of an SR with a gt2871r (and supporting mods but no head work) on e85 fuel. But these start to spool at 2000/2500 rpm and get 22psi of boost at 3500.

[Walperstyle]

I have not even finished building my engine, and I did a bunch of Turbo math, and realized that my GT3582R turbo is too big. I need the .63 turbine housing, otherwise, I'm going to be exactly where you are, or worse off, being I have V3 Crower cams 280s.

Degree cams properly, and get a smaller turbine housing.


btw, Garrett's website, along with a few books mentioned in my video are very helpful for anyone that wants to figure stuff out before they make mistakes.
update-Turbo Math, and what helped me - YouTube (http://www.youtube.com/watch?v=AasEZE3IK_w&context=C312d674ADOEgsToPDskKAIddGhArZwYfGEn6zagez )

[4x4le]

I wouldnt be able to stomach waiting that long for power, however it does seem that SHIT GETS REAL about 6k

[inopsey]

So Ive been trying to figure out why my setup lags so bad. Its a 3071r with a t25 turbine housing on an sr. Its bb and not blown. Its internally gated and the flapper isnt leaking or stuck open. Could it be the turbine housing inlet? Me nor the guys at ill garage have been able to figure it out, although they havent looked into it. Only tuned it and gave suggestions. Any ideas?
yuckk
http://i42.tinypic.com/10nyu6c.jpg

It uses a smaller turbine wheel then the T3 3071. It's modded to fit the housing not for performance. It's not an ideal setup.

T3 3071 Turbine Wheel: 60mm w/ 84 trim
3071 WG Turbine Wheel: 56.5mm w/ 90 trim

There are some threads around about the 3071WG's problems.

i use a 3071wg with a .64 turbine housing, and the only problem this turbo has is the internal wg. what problems are you referring too?

i use stock cams and see 15 psi before 3500 rpm, with full boost (22 psi) at 3700 rpm, this is using a shitty leaking hotpipe. on 18 psi i make 350 rwhp and over 500 nm of torque (on a dd) using a external wastegate setup. it holds 18 psi solid vs spiking with an internal wastegate with any gain on the ebc. i have thrown a lot of timing into the spool/low boost portion of the map. the 3071wg is a better matched turbo than a 2871 when comparing the turbine wheel to the compressor wheel, but is based on a t3 footprint, shoved and cropped into a t28 housing giving lesser results than a 3071 in a true t3 turbine housing with a true t3 turbine wheel.

[boost addict]

Honestly i bought the cam setup without putting much thought into it, i know it was dumb but im understanding more and more and it wont happen again. Im not on e85 right now because to my understanding the winter blends suck and my injectors are too small. Id1000's or something larger are on order for the spring and the fact that their are no pumps close to my house. I definitely dont want to run race gas and have to buy it by the barrel.

inopsey- Do you really think that cams and the smaller ar turbine housing could effect it that much.

walpaper- I watched your video and really want to get into the mathematics and research behind that stuff. Its always interested me just havent put the time into it yet.

[Walperstyle]

walpaper- I watched your video and really want to get into the mathematics and research behind that stuff. Its always interested me just havent put the time into it yet.

I just uploaded some videos of how to degree cams. Don't use my numbers, but it might help get you some bottom end torque.

...I have no life, sit in the garage and play on my engine. Tell my wife I'm still alive.

[Seraphim38]

Personally I think the biggest factor is that you are trying to feed the .86AR 3071R from a T25. That combo is too far apart in flow; the .86 wants to flow a lot and the T25 won't support it until it's really spinning. If you had a T3 top mount setup, go down to the .64 with an external gate and it should spool at 4k.

This is what I am debating about right now: whether to go from a .64AR bottom mount 2871 that is very responsive to a T3 top mount 3071R .64, which may give up 400rpm~ish of boost but will provide much more power overall.

[ForceFed]

I would double check the wg. I'm not disagreeing with everyone as that is probably to small of an exhaust side, but that graph starts to pickup at 4500 then delays for no reason... seems like a wg issue or something in the tune

[tunermt]

really looks like there is something mechanically wrong, i would lean towards boost leak, pre turbo exhaust leak or WG issue. That turbo on an SR20 with your cams (properly degreed) will make peak torque around 4200-4500.

What are you using to tune with? What does the timing map look like?

Boost leak and exhaust leak test it ;) DIY...another boost leak tester - Subaru Impreza WRX STI Forums: IWSTI.com (http://www.iwsti.com/forums/how-install/119676-diy-another-boost-leak-tester.html)

[boost addict]

It was boost leak tested and it wasn't leaking, there are no exhaust leaks, and the waste gate is about as tight as it goes and I looked in the housing at the flapper and nothing is obstructing it. I'm really leaning towards the turbine housing but Ive heard people say theirs hasn't had bad lag with t25 housings. I'll probably just buy a t3 housing and go top mount

[s14unimog]

Seems like a similar story to me. I was running a 20g with 264's and stock compression. The car was very fast but responded like a turd. After shattering the #1 ringlands last fall, I decided to up the compression to 9:1 and shorten the charge piping; i dropped about 4'. I have nothing to show for my efforts yet but I'm hoping it will make a difference. If not I'm goin back to stock cams. Revise and rebuild. Let us know if you see some real improvements with stock cams. I don't doubt that it'll change things but I wonder how much on high-er HP SR's

[4x4le]

Im yet to tune a nissan with aftermarket cams that have made me go, "wow that was worth it".

Idle sounds cooler, spools later, maybe a couple hp up top but its hard to say because I havent had any identical cars with the exception of the cams. Im just comparing graphs from similar engines and turbos vs cams being used.

Now Im not a fan of stock s14 cams (KA). I like the 248/248 swap in ka's


edit: because I feel I should clarify something

I know there is a reason for cams. When the turbo is huge, or if your n/a chasing every single hp then go for it.

If your t2 or small t3 I dont see why people bother.

[ForceFed]

If it were the cams it wouldn't have that little pickup at 4500. Are you running off just the wg, mbc, ebc?

[tunermt]

There is something wrong, that turbo with your build will make boost and power much earlier so long as everything else is working correctly even with the wheel and housing you ended up with.
What are you using to tune with? Do you have any data logs?

Get those cams degreed in!