on3 70mm turbo setup spooling strangely

[Mustang Matt]

Don't think cam timing is the problem. The motor would probably run rough if it was off side to side.

Won't a compression test tell for sure if one side sees significantly different compression than the other?

 

[Tims97SVT]

Won't a compression test tell for sure if one side sees significantly different compression than the other?

Besides this spooling issue what gives you the idea that the cam timing is off? In that bill you had it looks like 805.00 bucks charged to install cams. That better be timing/degree them too. Would a comp test tell you if the cam timing is off maybe but it can't be that off of the car would run like poo.

 

[Turbo98]

Most shops won't degree the cams in unless it's requested. It's very time consuming and I would think a task like that would be specifically called out on the invoice if that was done.

 

[Mustang Matt]

Besides this spooling issue what gives you the idea that the cam timing is off? In that bill you had it looks like 805.00 bucks charged to install cams. That better be timing/degree them too. Would a comp test tell you if the cam timing is off maybe but it can't be that off of the car would run like poo.

I missed that line with the $805. That's interesting.

Well here are my thoughts... The car has never run quite right. It dynoed NA around 250ish. My other car (a 98 cobra) on the same day and same dyno with a stock motor dynoed closer to 280. I assumed the HCI intake was costing me the 30 hp difference. These heads are also ported, maybe they're overported and there's not enough intake air velocity.

Even with 4.30s though, this car just didn't move that well. "Run like poo" was a fairly accurate description. It was completely drivable, it just wasn't as fast as it should be.

This entire time I've assumed it was built for boost, it just needs boost to be fast.

So I have a tuner I use that is well known in Missouri and has a great reputation for safe tuning. He literally cranks forced induction cars out of his shop. I won't list his name because I don't want these problems to reflect negatively on him. He works with on3 kits all the time and this is the first one he's seen spool like this.

5 months and $$$$ later. My car still runs like crap. I've kept in contact with the previous owner (I bought this car with the motor already built in 2007 I believe.) and I called him to see if he had any thoughts.

He said that compression was low on one side of the motor so he thinks he remembered one cam being advanced to compensate. It had been so long that he couldn't remember the details though.

I guess I jumped on the cam timing idea as a problem because even if it's not the problem, the factory cam timing is not ideal for a turbo car anyway. So I'll be improving performance and either fixing the problem or seeing with my own eyes that there isn't a problem. One reason a turbo wouldn't spool up right is if it wasn't seeing a correct amount of exhaust gas. One reason it wouldn't see the right amount of exhaust is cam timing. (The only other is exhaust leak?)

This is a huge learning process for me and I really appreciate all the feedback guys. I always learn a lot more when I'm dealing with a problem than just trying to read a text book.

I'm going to try the Tial wastegate first. (It should be here next week.) Then I'm going to do a compression check. I would have already done the compression check but I've misplaced my compression tester so I need to grab another one.

In the meantime, I've almost got my garage completely cleared and cleaned up ready for dropping the motor to check the cams.

 

[boosted2000si]

My last bit of advice is to find a second tuner for a second opinion.

I know you like your tuner but it really sounds like an issue in the tune. Why is the car breaking up?

 

[Mustang Matt]

That's a fair piece of advice.

After I swap the wastegate and do the compression check, I'm going to do some data logging and I may send it off to a few well known tuners to see what ideas they have.

 

[Mustang Matt]

Bolting the new wastegate on tonight.

 

[Mustang Matt]

Maybe marginally improved spooling but still the same overall behavior. So third wastegate and this time an American made one and same problem.

Next up is compression check.

 

[Mustang Matt]

I think I've narrowed down what pistons I have to:
Mahle #644-MOD220571I16
4.6/5.4 Modular Ford PowerPak Piston Kit
Forged 4032 High Strength Aluminum Alloy
Bore: 3.571''
Pin Diameter: .866''
-16cc Dome Volume
Compression Ratio @ 46cc: 9:1
Precision Ring Grooves for Included 1..5, 1.5, 3.0mm Rings

Which with 52cc b-heads should put me somewhere around 8.76:1 if I did the math right.

How do you convert overall CR to per cylinder PSI? That way I'll know what to expect.

 

[Mustang Matt]

Quick update...

Pulled the plugs. They were gapped all over from .035-.044. What causes gap to increase? It couldn't be detonation because there's no timing in the tune right now. I regapped them to .025 and will do some data logging after tonight's compression test.

Compression tester wouldn't hold pressure so trying a different one tonight.

Another thing to mention is that the spooling was linear even at 5-7psi as was the breakup above 5k.

 

[Mustang Matt]

Compression was:
1 - 156
2 - 152
3 - 146
4 - 150
5 - 160
6 - 149
7 - 158
8 - 155

Regapped plugs to .025

My friend Steve and I went to the backroads. After figuring out we had crossed 7
& 8 plug wires, we took it out for a pull. I could only go to 6k
because there was a curve I forgot about.

Car pulled HARD and didn't stumble and didn't stop pulling.

So we pulled over and looked at the data for several minutes.

Then we got to a straight and did a 2nd gear pull. It pulled so hard
the sct went flying and the cable came loose so we lost the data.

Then all of the sudden the car starts stumbling. I'm thinking... crap
I blew a spark plug out of the head. We don't have far to go so I'm
limping it back home but it starts dieing. Crappy wal-mart battery is
getting weaker and weaker each time. I get to the street before my
house and it's dead.

So I get my neighbor to help me out and we gather up a chain and a
flashlight and some tools and by the time we get back Steve has
realized when I got off the gas from that pull, the pressure blew the
intake coupler off the throttle body. I don't know if I didn't get it
tight enough or if this 50mm on3 blow off is crap or what. So we got it
tightened back up and jumped the car and drove it another 300 feet
home.

I'm going to work on the O2 circuit next. Currently stuck in open loop due to some really funky O2 readings even after new O2s and swapping them bank to bank.

Either way I was smiling from ear to ear. Jury is still out on the spooling issue, but the average of the banks was 151 vs 155.25 which seems like cam timing is pretty close to factory.

 

[CPRsm]

No timing=poor spool up