I'm next in line to get my engine on the dyno at my mechanics shop. The last engine just got off last night so I should be up on it today or tomarrow. This got me thinking and I forgot to get a good timing table set up for the engine.

I'm running an LT1 with mild ported heads(~250cfm) and a t76 ptrim with an a2a.

I was going to start with 30* at 0psi and do a 1*/psi drop across the board to start with. Do you guys think that this is too conservative, just right, too high? I'm planning on tuning for 7(street) and 15(track) psi all on 92 octane.

Let me know what you guys think.

 

a good place to startbut a bit too conservitive I think. our chambers are pretty efficient, it shouldn't need that much retard.

 

DUDE!!!!!!!!!!!!!!

Well.... whats that haps man.. whats the word? let us know!

Chris

 

I stopped by the shop yesterday and dropped off some gas for the dyno. My mechanic had been out all day because he little girl cut herself really bad and had to go get stitches. It took him pretty well all day to get that done.

I saw the engine, bottom end is together. It's about 2 feet away from the dyno haning in the air off a hoist. So its flywheel, mount it on the dyno and then slap the heads and intake on. A few hours of wiring and setup time for the turbo stuff and I'll be ready. When we'll actually get time to do it I'm not sure. It's kind of frustrating, but at the same time I can't expect to be his number one priority in life. So life goes on. I atleast saw the new Batman movie last night that I know I wouldn't have ever seen otherwise.

 

I've got an update. I went to the shop last night and guess what, the engine was sitting on the dyno. I stayed out there until about 11:30 bolting on random pieces that needed to be put on it. I ran into a few snags with the wiring harness and one of the header bolt holes.

Tonight she should be almost all the way together! And we should have her fired up sometime this week! I'm getting very excited now!

 

Cool, hang in there, you're getting close now!!!!!!!!!

 

Man you have GOT to snap some pics of it sitting on the dyno man!!! I wanna see I wanna see!

Chris

 

Well Chris, today is your lucky day or maybe mine. I got done working on it last night at about 1am and its all there, everything is hooked up. I went to hook up the laptop to find out if the Accel deal is hooked up right and I realized that the laptop I borrowed from work doesn't have a serial port on it.

So I bought some cables and tonight after work its going to be adding oil, swaping to 93 octane gas, setting the distributor, TPS and fuel pressure and it'll be good to go. Hopefully I'll have some stuff for you guys tomarrow. I'll be bringing my digital video recorder so I should be able to get some stuff this weekend for you guys. Wish me luck!

 

Did you get a USB to serial cable adapter?? I ask because I tried that with a Gen 7 system recently and the serial cable kept having communication problems. Craig Smith at DFI told me they have a lot of problems with communication with that adapter; better to get a laptop with a serial port. Just an FYI... BTW, good luck man!!! Hope she makes lots!
-Jeb

 

Hell yeah man... can't wait to here the results and see some pictures man.. keep us posted i am chomping at the bit over here in NC!

Chris

 

Well guys, you know how these things are always plagued with problems. So after I had to rewire the TPS sensor, Disable the codes that were causing it to lock the TPS sensor, plug the knock sensor holes, re-install the gasket for the thermostat, then the thing wouldn't start.

Guess what, no spark! So we decided to totally remove the stock ignition module and coil. We took the accel wire up stuff and wired it into the MSD 6AL that was bolted to the dyno, and an extra coil that was laying around. Then we had some spark, not sure what was up with the stock stuff, maybe something went bad or the wiring was messed up, we decided not to mess with it and do it a different way.

So we got her started and gave it a little gas, you could see the silicone elbow suck in when the TB plates opened. Kind of weird, but we tried to give it some gas, not a real pull but just something to make it work. I watched the map sensor go to -5psi at WOT until the turbo spooled and then it shot up to 7psi like it should. This would seem normal to me given that the turbo would be a restriction until it starts to spool up, is everybody else seeing this too??

We did run into three problems though.

1.) The last guy that tuned my car couldn't get the car to idle right so he drilled some holes into the TB plates to get it to idle right. Well with the much smaller cam these two holes are causing a vaccume leak and getting idle up to 2000 rpm or so.

2.) Second problem is the BOV. We hooked up a vaccume gun up to it and it takes 30 in of HG to get the thing to open. The engine will make 15-20 in after you slam the TB shut. But the other 10-15 in equates to about 7-10 psi to get it to open, but it didn't seem like it wanted to open at all, but its a tial BOV and there's no adjustment.

3.) I've got kind of a big exhaust leak around where one of the slip fit connectors for the cross over tube is. I was told that this shouldn't effect the O2 reading at WOT since the pipe will be consistantly pressureized and won't actually suck in normal air to throw off the O2. But I'll need to fix it eventually for the car to spool at a decent rpm. Anybody have any ideas besides welding it closed?

So today the TB should be fixed, and we'll hit up the tuning tomorrow morning. I've gotta say though, that thing sounded SWEET when it spooled up! It would have sounded even better if the BOV would have opened up afterwords too.

 

On #2, give her some time and it will work loose. Mine was sticky at first, a little marvel's mystery oil goes a long way.
On #3 go to the local truck dealer and get a stainless band clamp. the kind that are 3" wide, have a cast zinc Double "U" and the spreader bars. You know what Im talking about when you see it., Dont get the kind that just have staniless wrpped around 2 flat steel bars, those suck.
I have used the better variety to butt 2 pipes of equal dia together and it held for years (until I built the turbo) and I use them on everything I build today. At about $8 bucks you cant go wrong.

 

Outstanding man!!!!!!!! that is great new Brian! Glad you finally got to fire her up... I just went in the garage and tried a vacuum gun on my BOV as well.. its one of the Tial Knockoffs by XS Power.. same thing you got about 25-30 inches of vacuum before she opened.. i disassembled it and lubed it up a bit and it went down to about 20.. once the spring actuates a few times i am sure it will drop a little more as well as it "breaks in" looses some of its tension like valve springs drop pressure once they are set.. with some boost and the throttle plates shut, I think it will work just fine.

as for the spark... not sure man.. but if ya have it fixed.. good deal.. what are you running it on now? just the 6AL and an old style coil? lemme know i am curious..

so did ya get any footage man.. i wanna here some spool dude!

Chris

 

Chris, the ignition setup is this: The cam and crank sensors are hooked up in the distributor(Accel Dual Sync) and the one crank trigger reference goes to the MSD along with switched power. The MSD is then hooked to a coil that gets hooked into the distributor. Basically we are using the MSD as an ignition module. Seems to work great.

BTF, I got one of those band clamps, you're right they work great. It actually molds to the pipe features, very cool.

I should have some videos ready Sunday Night. But I might need someone to host them for me. My bandwidth limited sight won't support it. I'll keep you guys informed with what happens tomorrow.

 

Well guys, we's takin a break from this dyno thing for a bit. We are just getting the A/F stuff setup and running 23 degrees of timing or so. Hp numbers are 448 hp at 5500 and 464 tq at 4600, corrected to 468 and 484. This is all at 7.x psi. The guy says that his dyno is pretty conservative and it'll give closer to rwhp number rather than crank. I'm hoping thats the case as I dynoed at 350rwhp on pretty much this same engine with a bigger cam N/A.

Well, back to looking at data. I'll give you some more info when I get it.

After looking at the data it seems that the engine wants to have more fuel than just the 12.5:1 ratio. We're gonna try it at 12:1 and see how much it goes up. I'm still leaking a bit out of that one pipe I wonder if it's causing the O2 to read rich when its acutally lean?

 

Could be, if it's on the upside of the turbine it will read all farked up during boost.

 

We tried more fuel and it didn't help, it hurt. We had a storm front move in and it was actually starting to rain when we did the last few runs. That messes with the number by a good chunk.

We started adding timing and it liked it, we were up to 510 tq and about 500 hp corrected (489tq/475 un corrected) by adding some timing and it ran really lean after that, our best guess is that the fuel pump isn't keeping up anymore. We've been seeing the afr's going up slightly the last run ot two and the last one it went haywire. I'm gonna pull my walbros from my car and bring them out tomarrow morning.

For all you turbo guys out there, my 224/218 cam shaft falls on it's face after 6000 rpm. One pull went from 470hp at 5900 to 441hp at 6200

 

Where's the intake centerline of the cam ?

 

Did the boost go down, iat's go up at the last part of the run? you could be running out of compressor, or corking up with turbine flow.
you should consider tapping a 1/8NPT hole in the turbine using about 10 feet of copper 1/8" coil, and running one more boost gauge for turbine pressure,(even just temporarily) then you have the full pcture of what's going on in the sytem. Later if you don't need it anymore, just use the hole for a turbine inlet temp probe.
I went with a 230/224 on a 114+4. I hope to run to 7k with it, but your giving me doubts about that one.

 

The cam is on a 114 centerline.

I know I'm running out of compressor just from looking at the compressor maps. I'm borderline with a T76 turbo. You can hear the turbo start to screem more the last 1000-1500 rpm's of the run. I wish I could have gotten the video download of the run to work.

I did see the IAT's go up at the end of the runs but I'm thinking thats just heat soak from the intercooler. The fan, affectionatly called the "squirl cage", moves a bunch of air, but nothing like sticking you hand out the window at 40 mph.


Boost did seem to stay very steady. I did try that Gen VII vtech output to control a solenoid to regulate boost pressure. It worked, just very slowly. It took about a second between the time that it would open and close so the boost would swing from 12 to 6 and back. Next we tried cranking down the wastegate spring as much as possible. It did work, kind of but it didn't give the valve enough room to swing open enough so we saw some boost creep from 10psi to 12 at the middle of the run and then it started going back down to 11 at the end. But we did make 630 tq and 600hp on that run. Luckily those compressors get more efficient at higher boost. I over-nighted a boost controller and it should be here tomorrow afternoon. We'll see how things go when we up the boost.

So tonight I get to sit back, clean my house that I've been neglecting, and not have a beer since I haven't had time to go grocery shopping in the last week or two working on this thing.