Another KA-T on the road: pics, mixed results and questions

[Jurand]

First of, see signature for my setup.

Here are some pics:





Forgive the wiring, I'll clean it up once car is tuned right and all the bugs are fixed.

The wastegate is supposed to come with a 7psi spring and is a real Tial unit. The wastegate signal is coming straight from the compressor housing. I'm getting 5.5psi on my mechanical boost gauge at around 4k rpms with the silencer on the exhaust and 6.5psi with the silencer out (no cat, but I'm getting a 3" high flow soon). The boost gauge is T-ed off the BOV line which in turn is T-ed off the FPR vacuum line. Are my boost readings what you guys would expect? I think 0.5-1.5psi pressure drop through the intercooler (upgraded BD unit 24"x6"x3.5") is about right. Last night, it also spiked to 9psi at redline which seems to be "normal" with the BD manifold. I plan to turn the boost up maybe another 2-3psi due to this boost creep and the fact that I don't trust the e-manage too much.

Now, as far as how it feels - I get very mixed results. When cold, it seems to pull as well as you'd expect with 6psi on a T3. However, once it gets hot I get this loud buzzing sound at 3.5k+ rpms which seems to be the POS SSAC exhaust and the car loses power. Now, at first I was really freaked out and thought that maybe this was detonation. I'm pretty sure it's just the exhaust going into crazy resonance and vibrating like hell. I don't understand why this would cause a loss of power though. I have the AFR's set up for anywhere from 11-12.5 under boost (crappy datalogging with the LC-1) and timing pulled as much as 12 degrees to account for shift in the timing map with the airflow correction. I'm thinking that maybe the knock sensor is going crazy with all this vibration and pulling even more timing and killing power. Does that sound plausible?

On a funny note (funny to you guys, not so much to me), I couldn't help myself when we first took it out on Friday night and got a ticket for 66mph in a 45mph zone on a deserted road in the middle of nowhere. This was about 30 minutes after the turbo install was finished - maybe a new record. Just my luck that the one set of headlights a long way behind me turned out to be a cop. In the end it was my stupidity to be tuning/speeding on a Friday night when cops are out all over the place.

Let me know what you guys think. I'll try to set up a dyno session soon to see if it's really not as fast as it should be. Maybe all the time I spent riding a bike and in my friend's 400rwhp+ cars has ruined the feel of only ~230rwhp.

[sunnys14]

0.5 psi pressure drop with that small of an intercooler.... hmmm i would expect like 1psi pressure drop at anything over 14psi. i have a BD kit also and i have not experienced any boost creep. you should also unrestrict your exhaust (get a testpipe and run no silencer). what are you using at timing control? emanage? pulling 12 degrees of timing at 7psi seems like way too much... i hope u keep working out the kinks of that kit, i know i did but it should run just fine afterwards. good luck

[Jurand]

I'm running a test pipe for now and I took out the silencer. I want to get a high flow cat, though, because I feel like an ******* running no cat.

The 12 degree retard includes the shift in the timing map due to airflow correction. It really only retards about 5 degrees from 26 to 21 degrees of total timing at WOT. Basically, stock timing is 26 ---> with airflow correction (ECU reading less load) of 0.5 it's now 33 ---> 33-12 = 21 degrees of total timing. This is about 0.75degree/psi and the map was actually what Enthalpy (I'm about 95% on that) posted on freshalloy a long time ago.

[virus77]

you might be puilling too much timing which will make the car feel sluggish. I was running big injectors on my kat before and I was pulling a grip of timing to account for the "timing advance" but it was hurting the car alot. I ended up checking the timing of the car at WOT under load with a scanner and my total timing numbers were around 20-21 degrees on the stock ecu with big injectors. I originally had dialed in enough timing retard to counter the advance thinking I would be around 29 degrees. I ended up bumping timing around 8 degrees or so and the car just came alive. Basically you should get your total timing checked out. If your car has a working OBDII port ive got a pretty cool scan tool for sale in the link below my sig

EDIT: had a little more to say

I had always thought the timing bump would be pretty big but realistically your car looks at TPS and MAFS to get a load value, then it puts that load value against RPM for your timing maps. The stock mafs WITHOUT a turbo I recall gets to around 4.5v near redine, which would be the max end of the spectrum for the mafs value and you are at WOT so maximum load vs. rpm is used in the timing maps.

Lets say now you have bigger injectors, turbo and piggyback cutting back fuel. The Mafs at wot now is seeing 4.7-4.9 v and is being cut back to 4.4v due to injector correction but it puts you pretty close to stock NA timing numbers in the map. Although it is still too much timing for a turbo car its not as advance as people make it seem.

But before you bump any timing you should get your timing checked at WOT and go from there. And remember when you check timing at WOT on a scan tool and it shows 22 degrees and you have it retarted 12 and the emanage it means you timing is around 10 degrees. The scan tool doesnt know what you are retarding since it reads the timing value before the emanage intercepts it.

Modified by virus77 at 9:33 PM 11/9/2005
Modified by virus77 at 9:34 PM 11/9/2005

[Jurand]

Excellent post, thanks a lot. I was planning on getting some sort of scanning device to see what the actual timing was. I guess my (and others') thinking on this and assumption of linear relationship between MAF voltage and airflow is incorrect.

Emailed you about the scanner.

[Jookmasta]

whats the turbo specs? whats ur gap at? i run a str8 T3 and my base timing is at 15 degrees.......this is for 12 psi daily.

[Jurand]

It's a Boost Designs T3 which I believe is a rebuilt garrett super 60 trim with .48A/R.

[DammitBobby]

Does the compressor say ZY????

[Adikt]

nice to see another KA-T up and runnin in Chicago, my Greddy kit came in today and im starting the install sometime next week

[Jurand]

Does the compressor say ZY????

No, it says AiResearch like a Garrett.

[Jurand]

whats the turbo specs? whats ur gap at? i run a str8 T3 and my base timing is at 15 degrees.......this is for 12 psi daily.

I'm running BKR7E-11 plugs gapped to 0.035.

[240sxfan6882]

It's a Boost Designs T3 which I believe is a rebuilt garrett super 60 trim with .48A/R.

Those turbos are remanufactured by MJMturbo in Alabama. They are Garrett certified rebuilders. I've been talking to a guy who's bought 5 turbos from them (between himself and some friends) and he praises them and says he hasn't had a single failure yet. I got one also, t3/t4 60/.48ar, got it checked out by a shop here and they say it looks good. Your turbo should be ok. Just FYI.

[DammitBobby]

I got one also, t3/t4 60/.48ar, got it checked out by a shop here and they say it looks good. Your turbo should be ok. Just FYI.

As long as it doesn`t say ZY you are ok. Yes I visited the shop a month ago and got the same exact turbo you have. T3/T4 60/.48AR

[Jurand]

I pulled the intake off last night. The impeller spins freely and doesn't seem to have any shaft play. However, there does seem to be a slight groove in the housing. Is this normal or an automatic red flag? The moron who I bought this kit from (kit is used but supposedly only for 500 or so miles) had almost no packaging material around the turbo when he shipped it. I'll try to post a picture of it this weekend.

Also, I put a 0.060" restrictor on the oil feed line. I know there's no general consensus if these should or should not be used, but from my research most people say to do so. Should I try to take it out and see if there is a difference?

Thanks for your help guys. This is my first turbo project and I can use your collective experience.