questions about the L36/L67 Cartuning turbo kit....

[Guest TurboSedan]

i have a few problems with what i've seen with the new turbo kit offered by Cartuning for the Series-II L36/L67...

 

- what is the deal with the rear exhaust manifold? is the turbocharger run off one bank?. for $3000+ please tell me this isn't so....

 

Custom-made stainless steel exhaust crossover assembly -mates perfectly to STOCK exhaust manifolds or WPI Ported Exhaust Manifolds (coming soon).

 

running the turbo on STOCK manifolds or even TOG headers would lead me to believe the turbo is run off of ONE bank (the front bank). for $3000, i would certainly expect a custom rear manifold that feeds the turbine exhaust gases from BOTH banks would be included. i have no idea about the WPI ported exhuast manifolds...

 

- the turbo is apparantly not watercooled. not something i particularly like, but maybe it's not needed?

 

- where does the external wastegate dump to? does it dump into the downpipe or what? after studying the pictures on the 3800 Performance website, i really can't tell.

 

- what about the BOV? the Series-II L36/L67 is MAF controlled right? shouldn't the BOV be routed to the intake somewhere BEFORE the MAF? from the pics i've seen it seems the BOV vents to atmosphere.

 

for $3000 it hardly seems worth it. the 3800 Performance site almost seems to go out of its way NOT to show the rear exhaust manifold.

[skalor]

The turbo runs off of both banks, but the external wastegate only runs off of the rear manifold. There always arguements on clubgp about the external wastegate placement, and I don't really care for the wastegate placement either. They seem to work good though so that's the arguement for the wastegate placement. I think every intercooled CT turbo car is in the 12s. I think intercooled with the PT-61 they run about 15 psi. Charles(beyerch) from DHP has an Intercooled CT turbo kit on his '04 and he put down ~400 HP at the wheels.

[Aaron]

what is the deal with the rear exhaust manifold? is the turbocharger run off one bank?. for $3000+ please tell me this isn't so....

 

what about the BOV? the Series-II L36/L67 is MAF controlled right? shouldn't the BOV be routed to the intake somewhere BEFORE the MAF? from the pics i've seen it seems the BOV vents to atmosphere.

 

From what I can tell, it is run off both banks. It would have to be actually. But what they do is make a crossover from both banks, then include a plate to block off your downpipe exit. So both manifolds are stock.

 

On an automatic you don't really need a BOV. The only reason is for showing off the sound when you go from WOT to closed very quickly, of which most people don't do in automatics. The main purpose of the BOV is to keep the compressor spinning during shifts, to keep it from backing up on itself.

[dbtk2]

On an automatic you don't really need a BOV. The only reason is for showing off the sound when you go from WOT to closed very quickly, of which most people don't do in automatics. The main purpose of the BOV is to keep the compressor spinning during shifts, to keep it from backing up on itself.

 

And a BOV is a very good idea to avoid compressor surge, because everytime you let off the gas in a turbo car that doesn't have a BOV under boost the boost in the pipe going to the TB has nowhere to go since the throttle plate is closed except out the front of the turbo. This kills the turbo. A BOV prevents this because the boost goes out the BOV instead.

 

Shawn

[Aaron]

Everything you said is true and I agree, but in an automatic you aren't really letting of the gas drastically that much, unless you are doing it on purpose. Daily driving you let off, but not from wide open to closed, its more from barely cracked to closed, which wouldn't hurt the turbo any. So the BOV they have probably works just fine, I wouldn't worry about it any.

 

But if the car was mine, I'd be closing the throttle a lot on purpose to show off, and let people hear the BOV, so I'd want one. I'm just saying that if it is just a daily driver car, and you are semi careful, it isn't essential.

[Guest TurboSedan]

lol, i know what a BOV does, i was just confused about where it vented to. i thought the BOV should be vented back towards the intake stream on a MAF controlled engine, however, since it is mounted before the MAF sensor i suppose it could just as well vent to atmosphere.

 

From what I can tell, it is run off both banks. It would have to be actually. But what they do is make a crossover from both banks, then include a plate to block off your downpipe exit. So both manifolds are stock.

 

so the kit does come with a plate to block off the rear manifold dump?

[Aaron]

If it does what I think, yes it would come with a palte to block off the manifold dump. Not a bad idea, it keeps things cheap, but some shorty headers would help a lot.

[Guest TurboSedan]

after looking at the pics of the Cartuning kit a little more, it looks like the wastegate is actually coming from the rear manifold dump. so i guess there is a plate there; just not a 'blockoff' plate - more like a plate for the external wastegate to mount to. so like skalor mentioned, the external wastegate is only on the rear bank (i don't particularly like that either...wouldn't one bank run a little more lean than the other bank by doing that?). the other side of the wastegate dumps the exhaust gas into the downpipe. kind of hard to tell by looking at the pics.

 

http://www.3800performance.com/ct_ic_turbo_kit_pics.htm

[Aaron]

How would it cause the car to go lean? The point of the wastegate is to get less exhaust to the turbo, so it dumps it into the downpipe--bypassing the compressor. The wastegate can be put anywhere in the system before the unit, it is just generally put at the final Y before the turbo for ease. IMHO, that is actually a decent place to have it, it makes the system look really clean.

 

It looks like a pretty decent kit, the only thing I'd be worried about is that turbocharger, I personally would choose a different unit, a full ball-bearing type, but that costs money.

[Guest TurboSedan]

i really have no idea. a long time ago on the TGP forum i mentioned something about using a plain NA 3.1 MPFI rear exhaust manifold but instead of blocking the rear dump, mount an external wastegate there instead. i remember RedZMonte saying something about it running lean, or hotter at least on one side or the other (been a lonnnnnng time). i will hunt for that thread....

 

EDIT: here is that thread:

 

http://www.netavalanche.com/tgp/viewtopic.php?t=1958&highlight=external

 

i've never used an external wastegate so i'm not very familiar with them at all. both of my other cars use internal wastegates, which i much prefer.

[Aaron]

He was wrong about the exhaust manifolds, maybe he is on this as well.

 

I value his opinion, but I don't know how it would cause it to run lean. It could cause 1 bank to have less exhaust resistance, but since they Y at the crossover, that equals them out anyways. I do not think it would have any negative side effects. Try posting over at ClubGP, maybe some of them are running the kit, or know more than I do (<HIGHLY unlikely... )

[skalor]

There are quite a few CT equipped cars that hang out in the turbo section on clubgp. Like I stated, there have been numerous arguements over the wastegate placement in that kit. It could cause a cylinder inbalance, but L67s already have a cylinder inbalance from the blower and how it pushes air into the lower intake manifold. The good new is that the L36/L67 PCM has a cylinder balance table(IPW skew vs. cylinder) that shows which cylinders gets less or more air. This table skews the IPW to account for the flow difference. The table shows 1.00 on all 6 cylinders stock, but some aftermarket PCM tuners change the values so that they aren't all 1.00. 8)

[Guest TurboSedan]

Try posting over at ClubGP

 

i would if i could, but my computer doesn't like that site for some reason. i can't figure it out. it takes at least 5 minutes for each page just to start loading. i guess ClubGP just doesn't like my classic Mac and OS 8.6

[timg]

Josh,

 

Do you still have my phone number? If you want, call me and we can talk about it.

 

The wastegate on one bank is a BAD, BAD idea for running low boost (<7 psi). With a good turbo and a good exhaust system, the wastegate will not be able to vent enough gas to prevent overboosting. Since they're all running big turbos with >10 psi, they avoid the problem...

 

External wastegates typically dump into the atmosphere. It's not legal, but results in better boost control. Dumping into the downpipe is quieter and street legal, but degrades wastegate performance. Since the wastegate should only vent at full boost, your car should be as quiet as stock except for full boost. Wastegate dumps usually aren't loud enough to worry about.

 

BOV's can live happily vented to atmosphere on a MAF car IF they're vented to atmosphere before the MAF sensor. Most of the 3800's have a MAF around the TB so they're after the BOV. Mine used a MAF before the BOV originally and I had huge issues with it. A correctly setup Tial BOV will be open at idle and venting air from the turbo and will only blow off when you close the throttle rapidly. Tial BOV's have a variety of springs and you must choose the correct one. The application guide is on their site. DSM BOV's should be open at idle as should most others.

 

Watercooling is not necessary with older turbos and makes the install much easier. My T04E is NOT watercooled- my GT30R is. It is a benefit and can result in increased turbo life. For a modern Garrett GT series turbo, watercooling is a requirement. Virtually every OEM turbo is watercooled. Any BB turbo should be watercooled.

 

Hope this helps.

 

Tim

[Guest TurboSedan]

will do Tim, i still have your business card around here somewhere with your phone # on it. i've been wanting to talk to you about where you got your Turbo LQ1 crossover built.