Killowatt

My tuner has hit the proverbial brick wall at a mere 217 whp. The goal was 250. The setup is;

stock d16z6 bottom
head ported, oversized vales, crower springs, currently has stock cam, but also have crower stage 2 turbo cam
Greddy 15g turbo, manifold, elbow ( from new Greddy sohc kit )
8lb actuator spring
dsm 450cc injectors
Walbro 255 pump
3bar MAP
Mac electronic duty solenoid
BBK 62mm TB
Skunk 2 IM
2.25 charge piping
FMIC
K Teller down pipe
2.5 exhaust
eCtune
MFactory oil cooler
CX Racing radiator

Was running 5lb actuator and Crower Stage 2 cam. Would not hold more than 14lb boost, then fell to 10lb after 5500 rpm. Only got 197 whp.
Then we put the stock cam back in, and stronger actuator spring, and ran it at 13lb boost. Now the boost would hold until redline, more or less. Dyno tuned at 217 whp, 183 torque. When the rpm hits 6500, the boost warbles ( within 1lb ), and has pinging issues when pushed with more boost or less timing. Any suggestions as to how to reach 250whp? I have seen posts of other who have with this turbo.


Modified by Killowatt at 7:39 PM 9/5/2008


Modified by Killowatt at 6:16 PM 9/6/2008


Modified by Killowatt at 6:18 PM 9/6/2008


Modified by Killowatt at 6:19 PM 9/6/2008

boosted k20

post up a dyno chart. how much timing was the motor running? and what spark plugs were u using? also post a pic of your setup

HiProfile

First of all, thats not a large turbo by any means. The cast elbow makes it 10x worse. There have also been lots of issues with those greddy turbos' wastegates. Most people end up with more power when they seal them and go external.

When a larger lift/more overlap cam hits the floor at that RPM, it's due to way too much backpressure in the exhaust manifold. If you combine extra overlap and very high exhaust mani pressure, you get tons of reversion. That means dead gasses remain in the cylinder, so you're putting less burnable air into it.

chimmike

also, isn't the general rule of thumb that running more than 3x wastegate pressure doesn't work so well?

yeah, 15g is a small turbo, too.

Hybrid96EK

If you did those numbers on 8psi then I fail to see where you find the room to complain at all???

Killowatt

Ha! My only complaint is that we have not achieved the set goal, other wise the car is much more fun than the na version!

HiProfile

I was thinking about this again. There's a good chance that the restrictive turbine/housing caused the exhaust mani pressure to overwhelm the WG, pushing it open. If 5500-6500 is where all your problems are, chances are that's when it's choking up. If you had a dual-port actuator or external WG, eCtune could probably get you your 15psi at redline.

turbo sol

that is almost exactly the setup i am building now.

I too was looking at 250 hp but at the high end. I was thinking 225 would be a little more like it.

keep us posted about what you find out and if there are any "Secrets" to getting over that little hurdle.

Killowatt

My K Teller fit like crap too. The upper flange was not clocked to the correct position when welded in place. We had to hog out the bolt holes to rotate it slightly so it would clear the oil pan.
Last night was spent street tuning. We were able to smooth out the top 500 rpm, so it runs much better. Still running about 14lb boost, so were guessing the hp numbers are about the same. This seems to be as far as we can go with this hardware. About the only thing to change would be custom tubular mani. But every time I think of going down that road, I can't help but to think of scraping the 15g in favor of a gt2871r. That would take the project to a whole new level. And lighten my wallet in the process.

Killowatt

So you have ported a Greddy mani? we were afraid to do so, as we did not want to weaken it.

turbo sol

when you guys are talking about porting do you mean the log or the elbows?

i know this is "egay crap" and what not, but it looks like it would flow better.

http://cgi.ebay.com/ebaymotors...7.m29

doesn't help the elbow portion much though…


Modified by turbo sol at 1:22 PM 9/9/2008