ken louie

Are they that much better than the k-27's. I current have ape maf, k-27/6 and b&b exhuast. The car is my daily driver. I never had any problems with this set-up since I had it (1994), but some how I feel like I'm missing something? Are they that much quicker spooling up that the k-27's. For the $$$ is it worth the upgrade. Anyone in SF/bayarea has one that I can get a ride in? Any opinions would be appreciated

TIA

ken louie

79 930
86 951

TurboGuy

Ken,

The only one that would be faster spool is the the GT25. This is the only true BB turbo made. All other BB have a single bearing. The problem with the GT25 is every point on your car must be modified to adapt it. The turbo and mounting kit from Technodyne is over $3k ! and does not support the electric water pump and cannot be rebuilt. If it fails you buy a new one. Both will make the same power at the same boost but the GT25 will spool faster. If you are a racer and have the big bucks go for it. I just decided on a K27-6 using the new light weight turbin assembly. Much cheaper and is a bolt on. Good luck.

David J. Harrington

I just installed a Garrett T04E-54. That is not an expression, I literally just got the car running. It spools faster than my k26 did, however, I did make an intake modification. I basically made a custom intake with the stock AFM that emulates the Kokeln intake. I only did this to get it running for a couple of weeks(I cannot implement the stock intake because the turbos inlet is much larger that the stock turbo). I will have a MAF system in pretty soon, so my plumbing store intake will be out soon

I got mine[turbo] from TEC in Colorade, but only because I bought it before SFR started selling them. It has a custom hot housing for the 951. It also works with the water pump.

It is a completely different car. First and second gear are useless without more traction. They just spin when I floor it. I'll have my work cut out for me to get everything perfect.

Hope this helps,
Dave

Jerry

but how long will the car run if it's very stressed? do the easy things first. removing the cat will give you quicker spool up and the linsey boost enhanser makes 5th gear feel like 4th. it also necessary to have lsd and if you make the suspention better it is easier and cheaper way to go faster.

'86turbo

Dave hey whats up just wanted to ask a few questions. How would you rate this turbo on the practicality scale for a daily driven car? Did you go with the bb option? How fast is spool time. What wastegate are you running? What are your opinions on running this turbo with the stock wastegate? How much for entire setup(turbo, options inc)? Any draw backs so far? Are you running a mbc? Man no rubber through 1st and 2nd sounds like a monster!

David J. Harrington

86turbo-

Practicality- right now, it is good for a street car. I am a bad person to ask, though. I drive around with 400# springs and stiff swaybars and call it streetable. It is all an opinion.

I got the thrust bearing put in, which adds durability for boosts over 17psi.

I haven't checked the RPM at full boost yet. I have been watching my AFM and boost gauge too much. If I had to guess, I would put it at 2800-3200 RPM.

I am running the stock wastegate, but will be converting mine to a dual port as soon as I can find a supplier for diaphragms(froom some rebuildable wastegate such as TIAL??). It doesn't bleed off boost as badly as with the stock turbo. I believe this is due to this turbos larger exhaust and less backpressure.

I paid $1200 for the turbo. It came with a custom-cast exhaust side for our cars, and the thrust bearing option.

Only drawback so far: since the inlet is so much larger than the stock's, I had to seriously modify my intake. I could not implement the rubber plenum with this turbo, so I made a custom. My AFM is connected directly to the turbo with a rubber reducer for a toilet pipe. I had to weld a couple tubes onto the AFM(after the "barn door") to attach a couple hoses(crankcase breather and some wierd small line that goes up kindof by the brake booster). I could get a hose to bend the right way to attach the air-recirculating valve, so I modified it into a blow-off valve.

The problem is that the stock valve will be open at idle due to the vacuum, sucking in unmetered air. You only need it open during boost when shifting. Luckily, the vacuum during shifting is higher than during idle, so I needed to make the spring inside stronger(to not open at idle, but open during shifting). I opened it up, cut the spring almost in half, then added shims to make the spring the proper length. It worked perfectly and will get me by until I have a real blow-off valve. BTW, the sound it makes really is addicting.

Before the AFM, the cone is placed in the standard MAF kit place(right in front of the resovior).
I am running a manual noost controller, but will probably switch to a digital one soon(to control boost in a specific gear so that I don't go through these tires too quickly).

I get a full 17psi in first gear.

Let me know if I can give you any more info.

Dave

DanD

Not that I can read it, but here is the compressor map for the T04E-54 turbo. And the URL where I found it.


Garrett Turbo maps

My question is, at the following site I found T04E turbos going for less than $800. What is the difference between these and others T04E turbos.

Turbos for cheap??

I notice that the Porsche turbos were almost twice as much at the same site. Do they have integrated cooling or something?

http://turbochargers.com

Not endorsing these guys, just found the web site and was wondering....

David J. Harrington

Dan, to read that chart, for a boost of 17psi, look on the y-axis at around 2.2(17psi+ATM=2.2bar). Then, you must find the flow of your engine to know where in the x-axis you are running. I don't remember 100%, but I believe I calculated that as 25lbs or so.

I thought that I would lose a great deal of response with this turbo, but that was acceptable because I was going to use the car mainly on the track. I haven't lost anything, but instead gained some low throttle response(probably due to the less restrictive intake).

As far as the turbos go, I believe the Porsche units on that site are probably the equivalent turbo to what I have. The stock T04E exhaust housing will not bolt into our cars, and I am not sure if T04Es are originally watercooled, but mine is.

I am happy with my price. I would have been happier had I bought one from TurboTim(to keep the money in the Porsche community), as his prices are just as good as TEC(plus you get direct advice from his on the specific application). Unfortunately, I bought my turbo before he was selling them.

Dave

DanD

Dave,
thanks for the update.

I'm still a bit lost on the maps. What is the 25lbs? How is it calculated? What is the target position on map?

Sounds like you made a good choice of turbos. What made you decide on that one? Do you know which Turbo Tim sells that would match your Garrett?

Thanks,
DanD

David J. Harrington

Dan, the y-axis is the ratio of boosted air to atmospheric air, all in absolute pressures. If I am running 17psi of boost(or 1.2bar of boost), then the absolute pressure of the boosted air is 14.7psi(the atmoshperic pressure, or 1bar) plus the 17psi(1.2 bar) of boost. This gives me an absolute boosted pressure of 2.2bar(1bar+1.2bar). On the chart, P2C is the boost, P1C is the atmosphere, so assuming sea level, at 17psi of boost, our P2C/P1C is 2.2 bar(2.2/1=2.2)

I actually sized this turbo a little big, as previously mentioned, but I am not bothered by any effects. The flow of this turbo, if tuned properly, should allow for about 400HP at the wheels, but I don't forsee any numbers like that. Maybe 350 at the wheels.

The 25 lbs in my post is pounds of air per minute in our engines(IIRC, I calced this for a 3L engine, which I will be moving up to shortly). To get this, you basically calculate how much air the engine moves at certain RPM based on boost pressure, displacement, et cetera.

Ideally, you want to be in the most efficient range of the turbos operation(that is what those percentages are). The more efficient the turbo, the less it will heat up the air, reducing detonation potential and adding more power due to the more dense air. I am pretty sure my turbo is between Tim's stage 3 and stage 4. You should give him a call. He will be able to explain to you exactly what is going on.

Hope this helps,
Dave

Danno

Ken, come to our Bay Area Pizza Run on the Sat. after Thanksgiving! I don't have a Garrett, but a Huntley Stg.2 K26/Garrett hybrid you can try out. DanD, hope to see you there too! http://forums.rennlist.com/scripts/rennforums/ultimatebb.cgi?ubb=get_topic&f=19&t=0000 75

Ok, I will probably get assassinated for this, but here's a K26 compressor map:



You'll have to do the metric conversion yourself.

And as for the efficiency of a turbo, compressing air will ALWAYS heat it up (PV=nRT), but it's a matter of how much boost you can produce for how much of a temperature increase. Anyone recorded their intercooler inlet & outlet temperatures with the bigger turbos?

David J. Harrington

Danno, I will forever be in debt to you for posting that map. I love you.

Dave

TurboGuy

Danno,

Now that the cat is out of the hat how about the map for a K27/6 ?

DanD

Only if I get a divorce between now and then. We have a couples weekend in Montery that weekend. I was hoping to join you, I know you could tweek my ARCII a bit.

Maybe next year!

Paulyy

wow, i cannot believe a GT25R was mentioned to use on our engines!
it would probably choke before it makes 260 rwhp