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DIY Turbo Discussion greddy on a 1.8? homebrew kit?

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Old 10-30-2007, 09:17 PM   #1
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Default The brg lives again!

After taking my freaking time, the brg is up and running again. Actually, it was running a few days ago and still some minor issues to track down, but today I went out for some serious boosted runs. Started gently at just 5-6psi, but couldn't wait much so once I had a decent tune on the MS, cranked it up to 12psi after about 5 minutes.

The replacement 1.6L engine no longer has a GReddy setup, but a BEGi manifold/DP with a MSP turbo (GT2554R). I figured that the new 1.8 will get the big power setup so decided to try something a little different on the 1.6. Few notes/observations below:

1) Coolant reroute is not leaking anywhere....yet..... Can't find my old logs for comparison and my coolant sensor to MS is acting up so no data to share at this time.

2) MS motor mounts were totally worth it. Mild increase in NVH, but much improved shifter feel as well as less engine shake on startup/shutdown.

3) Compared to the GReddy, GT25R is definitely down on power (at the same boost level as it should be b/c it's moving less air), but spools considerably sooner and power delivery is much smoother. The car is deceptively quick as the power comes on very smoothly, as it doesn't have that "wait... wait... wait... hold on tight" feel of the GReddy. Probably would spool even earlier, but I currently have the 2.5"DP to the stock 1.75" cat then to a 2.5" exhaust b/c need to pass inspection before I slap on a HF cat or test pipe.

4) I think I finally get what "come on cam" means as even though the turbo is producing lots of boost below 2.5K rpm, it doesn't really start pulling hard until after 4k rpm. I can be at 10 psi of boost from 2.5K rpm on, and it pulls well, but there is a pronounced increase in torque after 4k rpm when the cams really kick in. Heck, I think this is one of the few turbos where custom cam gears/grind would be better suited for lower rpm power b/c the early spool.

5) We'll see what she lays down on the dyno, but for a track/fun car, I'm pretty happy to have an early spooling ~200hp car that will hopefully be reliable and I don't have to worry as much about the clutch/tranny/rear end/overheating/etc.... at the track compared to a much higher HP car. Now to build the 1.8 to satisfy the power bug....
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Old 10-30-2007, 09:34 PM   #2
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Really good to hear you got it back up and running! How long was she out for again?
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Old 10-30-2007, 09:35 PM   #3
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Old 10-30-2007, 09:38 PM   #4
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Really good to hear you got it back up and running! How long was she out for again?
Killed the motor at the last dyno day in May so about 6 months. I believe braineack or y8s has some good pics/vids of the big puddle of oil and smoking car.....ahhhh...the memories of my first (and I'm sure not last) blown motor....:gay:
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Old 10-30-2007, 09:41 PM   #5
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glad you got everything running smoothly!
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Old 10-30-2007, 10:05 PM   #6
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nice work tom, i'm still working on the gf to let me go to the dyno, she thinks i'll blow up this time and won't be able to make it home in time.
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Old 10-30-2007, 10:07 PM   #7
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since you asked.

oil comes out:


oil goes in:
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Old 10-30-2007, 11:01 PM   #8
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Good job getting it back to life.
Maybe an auto intake cam would suit that turbo better?
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Old 10-31-2007, 02:11 PM   #9
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Quote:
Originally Posted by brgracer View Post
After taking my freaking time, the brg is up and running again. Actually, it was running a few days ago and still some minor issues to track down, but today I went out for some serious boosted runs. Started gently at just 5-6psi, but couldn't wait much so once I had a decent tune on the MS, cranked it up to 12psi after about 5 minutes.
Quick question.

Are you saying that once you have a tuned MS you can increase the boost without retuning?

Something tells me no based on what I read in the megamanual on how it calculates fuel. Unless I am mis-understanding you.
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Old 10-31-2007, 02:28 PM   #10
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tuning fuel for boost is easy.

you gotta think in terms of a table. if you're running 8psi and then 12psi, it's pretty much a few rows to tune on the fuel table. I'm tuned from 1psi to 18psi.
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Old 10-31-2007, 02:41 PM   #11
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Quote:
Originally Posted by Saml01 View Post
Quick question.

Are you saying that once you have a tuned MS you can increase the boost without retuning?

Something tells me no based on what I read in the megamanual on how it calculates fuel. Unless I am mis-understanding you.
you're right, you can't do that. you have to actually run the car at that boost level to know if you've got the fuel for it. maybe only once, but at least once.
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Old 10-31-2007, 02:41 PM   #12
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Quote:
Originally Posted by Saml01 View Post
Quick question.

Are you saying that once you have a tuned MS you can increase the boost without retuning?

Something tells me no based on what I read in the megamanual on how it calculates fuel. Unless I am mis-understanding you.
Short answer, no. I knew I had a very conservative map so I didn't worry and kept my eye on my WB and poor mans knocksensor (ears+opg).

Long answer, I already had old maps from my old turbo setup with fueling/ignition to 15psi so I was running the new setup at 5-6psi to make sure that the map was not too far off. Once I saw on my WB that I was actually going very rich (9-10AFRs) and that I had changed the ignition map to a much more conservative map, I felt comfortable turning up my boost and going out for logged runs for megalogviewer. I've been tuning little by little, and if anything, I've reduced my fueling map and increased my ignition map.
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Old 10-31-2007, 03:00 PM   #13
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Thanks guys, I got it.
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Old 10-31-2007, 03:54 PM   #14
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Lets see some pics!
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Old 11-01-2007, 02:32 PM   #15
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Lets see some pics!
I took a few today. Still have to clean crap up in the engine bay, modify the GReddy heatshield to fit (instead of my awesome license plate heatshield), and get some piping to fit the smaller air filter behind the headlight lid duct (as well as lots of other stuff I'll find as well). Plenty of zip ties you can't see (and I burnt one and dropped it on the ground for my homie braineack :gay.
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Old 11-01-2007, 02:47 PM   #16
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Old 11-01-2007, 03:17 PM   #17
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Scott,

It's a dual port wastegate so you can either connect the second port to a lower pressure line or have a little more complex solenoid setup to get a little better boost control by having the spring + pressure holding the wastegate shut. Leaving the 2nd port open to air basically relies on the spring like a regular wastegate. The way you have it pictured, when my mbc opens up, both sides of the diaphram will be pressurized equally and my wastegate won't open.
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Old 11-01-2007, 03:38 PM   #18
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it's supposed to work that way, if the mbc has a small bleeder on it the pressure will be less, so it can overcome the backpressure. either way works.


i also forget it should be a regulator valve, not a simple mbc.



and that the boost should go into the top port not the lower.....ahhhh.





i = teh fail.



whatever, wanna race?!
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