Project: Huron Speed + 1999 Z28

[sman]

Damn, you were cruising! What springs did you go with? Those are BLUE!

[1999Black_Z28]

Damn, you were cruising! What springs did you go with? Those are BLUE!

LS9 springs from Lingenfelter. I figured I don't need much spring for a stock GM cam

[Nocooler]

LS9 springs from Lingenfelter. I figured I don't need much spring for a stock GM cam

They are mustang springs....

Dave you'll just have to keep an eye on back pressure, if it starts creeping up it might float the valves in the higher rpm's. A lot of guys run into this - plenty of threads on LS1tech. Should have read the thread closer and told you to look into duals before you assembled it.

But I'm sure you've done your research - and it'll be all good

[1999Black_Z28]

They are mustang springs....

Dave you'll just have to keep an eye on back pressure, if it starts creeping up it might float the valves in the higher rpm's. A lot of guys run into this - plenty of threads on LS1tech. Should have read the thread closer and told you to look into duals before you assembled it.

But I'm sure you've done your research - and it'll be all good

Thanks Jeremy, you're right. I've read about the backpressure issues and I went back and forth on this. What it came down to for me was this:
-The LS9 comes standard with a larger cam and runs more boost than I will
-I do not plan to run over 6k rpm's
-For every one with valve float issues there seems to be 4 or 5 running 100k+ mile truck engines to 20psi with stock worn out springs

Worst case I have to swap springs at a later date but it was worth the chance to me. Let's face it, high performance springs are not the most reliable so I wanted to try my luck with GM springs. The added bonus is that they only cost $70 but cost was not the deciding factor.

[Fbomb]

For the coolant crossover when I installed my FAST, I ended up cutting up the stock LS1 crossover and heating and bending. I then ran heater hose between the ports in front of and behind the manifold.

[1999Black_Z28]

The new pushrods were waiting for me when I got home on Thursday and my company was closed for Good Friday so I made some good progress this weekend. On Friday I double checked the length and installed the pushrods, installed spark plugs, coil packs, oil catch can, exhaust, and added oil and coolant.

Saturday morning I spent some quality time with HPtuners to write my new base tune. I used stock Z06 VE and timing tables to match my Z06 cam and LS6 intake, used the Banish injector data for my injectors, and I converted to the 2 Bar Speed Density operating system. After that I performed a “write entire”, double checked everything under the hood, and turned the key.

The Good: It fired right up and found stoich on my wideband very quickly.

The Bad: There was a loud hissing sound and the idle was high...sure sign of a vacuum leak. After feeling around for awhile my hand found the back of the intake manifold and located the source of the leak…it was where my MAP sensor connects to the intake. I was able to change the hissing and idle by pushing on the MAP sensor.

My new 2 Bar MAP didn’t come with a new seal so I used the old dried out one and didn’t give it a second thought at the time. A quick internet search turned up GM p/n 16194007 so I placed one on order Saturday afternoon. Unfortunately I will need to remove the intake again and wait for shipping but luckily it doesn’t appear to be a major issue.

On Sunday, after all the Easter festivities were over, I took it for a short, easy drive around the block. The first reason was so that I could check the functionality of my new MAP sensor and secondly so I could get another heat cycle on my valve springs. With key on / engine off my MAP sensor reads 0 kPa instead of 101 kPa like my 1 Bar MAP did. With the car running at idle it read around 40-45 kPa (like expected) and seemed to react correctly during my short drive. After verifying the fueling was close I went WOT briefly and the MAP went to 100 kPa just like it should. I’m not sure why it reads differently with the key on / engine off but it seems to work fine when the car is running…anyone have any insight?

It’s very weird driving the car with the Z06 cam and stock exhaust compared to my old Pat G cam with long tubes and cutout. The car is very quiet and smooth (other than the Detroit locker going around corners). I will post a before and after idle video once I get the new MAP sensor seal installed.

[Nocooler]

Nice Dave - another trick on the map is to tap the hole, install a barbed fitting and then run a line to the map. This way you don't have to worry about blowing it out of the intake under boost.

[1999Black_Z28]

Thanks Jeremy, thats a great idea

[Nocooler]

Yeah I need to do it to my FAST intake next time I have it off.

[DETROITMUSCLE]

very good progress from this project thus far congrats on being on the verge of drving the car again. How long do you plan to run the car on motor before throwing the kit on? Also did you decide on a turbo yet?

[SS4Matt]

As Jeremy said, every line on your intake you will want to add hose clamps or tapped fittings (your brake booster vac line on the back of your intake and where it goes into the brake booster itself will need hose clamps. your map lines and what not as well. where the stock map sensor plugs into the back of the intake. I used i think a 1/4" pipe threaded in that had a T that uses the push to lock lines that ran to each of my map sensors (one for the BS3, one for the Gauge) then I have a single push to lock towards the front of the intake for the vac reference

[1999Black_Z28]

very good progress from this project thus far congrats on being on the verge of drving the car again. How long do you plan to run the car on motor before throwing the kit on? Also did you decide on a turbo yet?

Thanks Jeff! I only plan to drive it a short while to work out the tuning bugs (injectors, speed density, etc) before installing the kit. I figure it's much easier to take care of these things before I turn up the boost. Hopefully it will be back under the knife within the next few weeks and when it emerges with a turbo I won't have to worry if the thing will start, idle, etc.

I'm still undecided on the turbo but I'm starting to think the on3 is worth a gamble at just over $300. The car has a manual trans and is primarily street driven so I want something that spools very quickly and that's why I'm leaning towards something in the TC76 size range...

[c0ncEpT]

I don't think you can really go wrong with either. $300 for a new turbo is hard to beat. Used TC76's seem to be going for around $800.

[1999Black_Z28]

I don't think you can really go wrong with either. $300 for a new turbo is hard to beat. Used TC76's seem to be going for around $800.

A lot of people ask around $800 for a used TC76 but I would buy a new one from Summit for $734 shipped to my door

http://www.summitracing.com/parts/TNT-11534/

If you search Turbonetics Hurricane series (vanessa 11534) you will see that it is dimensionally the same as a TC76

At first it seems like a no-brainer to buy the new TC76 from Summit but t-netics seems to be having an increase in quality related issues and I'm not sure they are any better or different than on3. I almost feel like your are paying $400 extra just for the turbonetics name...

[DETROITMUSCLE]

I would surly try a ON3 turbo they seem to have great standings within the mustang community and I believe summit or jegs even sell their kits. Jon will take care of you with any company he works with as well.