Fast4525

I am seeking turbo upgrade advice for my 1988 turbo S.


In a previous thread I was looking for 350whp on 92 octane but I have come to understand that this is a bit ambitious
unless I am willing to spend lots of money or live with lots of lag.

My new goal is to hit 300rwhp - 325rwhp on a Dynojet (91 oct) with fast spool and lots of area under the curve. My package will be simple - Upgraded turbo, 3" exhaust,
MAF + piggyback (undecided on brand), larger injectors, 3Bar FPR, TiAL 38mm and MBC). I will probably use a "dry" turbo to keep the installation simple and to eliminate
some coolant lines under the hood. Dry turbos last a long time on 930s so they should be fine for our cars if they are well cared for.

After reading many turbo-related threads on this forum I think a K27/8 would give the top-end power I want but it will spool too slowly for my liking.
A K27 #6 has too much exhaust back pressure which is why I want the #8 hot side.
Am I correct in thinking that a 47-49lb/min compressor is big enough to reach my power goal? What does a K27 7200 compressor flow?

Example:

LINDSEY "SUPER 48"
Available in 360° or TBB
This turbo utilizes a 48# per minute compressor wheel packed in a TO4E compressor housing. Inlet size is 3" (OD). Your choice of wet (water jacketed) or dry (oil cooled) frames.
This turbo is capable of 480 HP and flows 696 CFM @ 1 bar. It is comparable in size to a K27 in size and power output.


What is the modern bolt-on equivalent of a K27/8? A high tech turbo with modern aero design should be able to beat a K27/8 in terms of spool, response and top-end power.



<OT> Is the A/R of a K27/8 closer to that of a Garrett .48, .63 or .82 T3? IMO, a 2.5L 8V engine making in the area of 325rwhp where fast spool is the goal should use a Garrett .63 A/R T3 housing.


Even after all the reading I have done I still can't figure out which turbos are direct bolt ons for a 951 Do I have to buy from a Porsche place (LR, etc) or will an off the shelf Garrett fit?
Something like a T04E .63 or a GT3071 .63? Like this http://www.atpturbo.com/mm5/merchant...egory_Code=TBN


Advice and suggestions please

P.S. If anyone has a good K27/8 7200 for sale I could be convinced to go back to the old school

elargentino

You do not need the #6 - 8 hot side on a K27 hybrid to reach your goal.
I have made over 400 RWHP (many years ago) with minimal other mods using a k27/6 and 22 psi (If I remember right) PSI.
The KKK series is very robust.

If you are looking for more modern...
I personally have had excellent results on the 951 with Vitesse turbos.
And very good times with GT's on Audis.

Fast4525

My $0.02 is that anything over 300whp with a #6 hot side creates too much back pressure.

400rwhp at 22psi with a #6 hot side What octane?

I can't find much info on the Vitesse turbos.

Scott H

http://www.pauertuning.com/index_fil...gyourturbo.htm

Read through those links.

What your basically looking at is a Garrett DBB 50 trim (check out the compressor map, nice and wide islands and a nice match for our engines), with a Stage 3 turbine. That will give you good punch around town and you will run out of nerve before it runs out of top end on a stock 2.5L.

There is a thread on here, by nize I think, where he runs this turbo and gives his spool up results and dyno charts.

86 951 Driver

Why does the K27/8 get a bad rap on here? Exactly how bad is the spool on this?

elargentino

I agree with your #6 asessment, I was just giving my experiences.
vitesseracing.com should give you more info.
Octane was 104, probably, but your goal is only 300-350, so that would be well within that range - that was really my point.
Here is an old run from a K27/8 - can't find the k27/6 runs - that going to bother me now.

JohnKoaWood

Dont forget the Garrett T3 housing is NOT bolt on to our exhaust, nor are the garrett dbb center sections bolt on to our mount... there is more to cracking the nut of installing the DBB Garret T3 turbos than just bolting it on...

I realize the pricing makes them attractive, but for the 951 equipped with a KKK turbo, you are limmited to simmilar KKK turbos for bolt on, or doing 2-3K more in changes to make a more mainstream turbo fit...

just my 2C

IIRC LR is doing garret based turbos, with replica KKK hot side housings, to make them "bolt on"... but there are additional changes to be considered...

elargentino

Sorry - I may to apoligize here - I am getting old.
I could have sworn we did over 400 with the 6.
Here is a 6 chart.
Maybe I was thinking of the 8.
I will keep looking.
Stock exhaust, and cylinder head, here.
Lousy picture - max - 330/347

hot-J

a GT2871R will give you great spool, and 320ish+ rwhp. so will a vitesse stg III. assuming you have the proper supporting mods

SteveIX51

What you describe is pretty much exactly what I have on my car right now, with a Vitesse stage III kit (turbo, MAF, chip, piggyback), 3 bar FPR, 72# injectors, EBC that integrates w/piggyback (as opposed to your MBC) also from Vitesse, TiAL 38mm DP WG, and 3" powehaus exhaust (no CAT).

I haven't had a chance to tune or dyno yet, so I don't have a chart for you, but I'm pretty sure that I'm in your desired HP range, and spool-up feels good. I also don't have the specs of the turbo I got in the kit for you, but John at Vitesse is very helpful and I'm sure he can answer any question you may have (he's also on this forum all the time -- fast951). The turbo is not "dry" as you seem to be interested in, but a big advantage of the kits from Vitesse is that they are basically bolt on and easy to install, as has been touched on in this thread already, so that aspect shouldn't pose any extra headache.

86 951 Driver

It looks as if the spool up of the K27/8 and K27/6 are about the same? Hmm that really makes me want to go with a K27/8 since I already have one.

67King

That exact turbo popped into my mind immediately.

Scott H

Every "bolt on" DBB turbo is using a Garrett T3/T4R DBB CHRA, with whichever style T3/T4 wheels you want, whether it be Garrett, Turbonetics, Precision, doesn't matter. Then they use a replica Turbonetics #8/#10 (just go with the #10) KKK hotside sized for the T3 turbines and a T04E/B compressor housing and it will "bolt on."

Garretts true GT series CHRAs do not fit without modifying the mount, they are narrower than the T3/T4R CHRAs. Regular T series bolt right up to the factory mount, just need to adapt oil and water lines.

The Lindsey Super 48, SFR Turbonetics Stage 1, and the Pauer turbo recommended above are, for all intents and purposes, the same turbo. Same compressor wheel, same turbine, same hot housings offered. The only difference is that the SFR S1 may use the ceramic BB center section which once again has only a marginal effect on overall performance compared to the Garrett DBB. SFR isn't specific on what center section they use, but since it's a Turbonetics branded turbo it's safe to assume.

A 50trim will perform 95% as well as a GT3071R but with much less headaches. If you want to pony up the other $10k (because you know, "while you're there" changing the crossover and adapting the mount you may as well add the SFR Stg 2 headers, some headwork, an intake manifold, MAF and tuning). If you don't do all of that other work then the benefits of the T3 let alone a true GT hotside and turbine won't be utilized to their full potential so what is the point?

If money is no object, then by all means go ***** out. But if you want a quick, reliable, relatively cheap conversion that performs 95% as well as a car with all the bells and whistles then the KKK hotside, stock headers and crossover are just fine.

I strongly suggest reading the FAQs I linked to in my last post. It's the most straight talk that you're going to get from a 951 tuner regarding turbos on our cars.

racerxrick

Next Tuesday I should have dyno numbers on my very basic build. I went with LR's Super 53 over the 48. Dave Lindsey said that spool up will be within about 100 rpm of the two. Initially I was disapointed with spool and then discovered a vacuum leak at the blow off valve. I have been very happy with the performance PLUS with the addition of a MAF and larger exhaust will improve greatly (along with higher boost levels!).

I still have the stock AFM and only a 2 1/2" exhaust with test pipe. Other basic mods are listed in my sig.

Dyno pulls are scheduled next Tuesday at 11am!

KuHL 951

I have the Garrett T3/T4R in 50 trim from Pauer Tuning and yes it's a direct bolt on. The water feed pipe needs to be lengthened just a bit for better clearance and a restrictor installed on the oil inlet due to the BB design. The alternator cooling shroud needs to be trimmed also to allow better fitment of the hose. Other than that all it needs is indexing for optimum fitment.