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HybridZ

Little update on my Z.


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We'll my 240z has spent the last 6 months or so at a local shop. I originally took it there thinking it's only going to need a tune and I should be good to go. We'll as we all know things never go as planned. Supposedly the Edis box that I had controlling the coil on plug setup wasn't firing correctly and $1500 later I had a new accel system no longer using my crank trigger but a one off dist system running off the cam sensor. We'll that system wasn't compatible with my old gen 1 fast system so out that came and in went a gen 7 sytem. Figuring all that out took this place about 5 months. Now got the car running better and on the dyno it went. Then the new problem came up. The car put down a whopping 400rwhp on 21lbs of boost!! Ya I know!! So they took the blower off and it put down a incredible 198rwhp.

 

Now one thing I noticed when I 1st fired the car up 2 years ago was that there wasn't much air coming out of the exhaust. You guys have seen the old video, the car thumped out air at idle before. The shop I had it at seemed to think the cam timing was off and that was why air wasn't flowing through. We'll the cover was pulled and the cam timing is dead on. Also when this work was being done my guy told me that the intake manifold and intake runners were full of exhaust soot, all the way up to the throttle body!! What the hell could be causing this? This motor was a fresh rebuild although it did sit for 8 years or so before being fired up. Also the motor shouldn't be making 21lbs with the pulley combo I have, maybe like 15-18 at the most. This has to be a head related problem. Cam doesn't look flat, what the hell could be causing this?

 

I'm having a hell of a time getting this car back on the road, it's been over 9 years since the original video was made.

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Valve lash OK?

 

Cam timing OK? Double check intake and exhaust CL on several cylinders, verify overlap and opening and closing points.

 

Piston to valve clearance OK? If the cam got put in wrong you may have tagged the intake valves.

 

jt

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What are the specs on your cam?

 

Forced induction engines don't like too much overlap.

 

not sure, it's been so long I can't remember and the machine shop doesn't have any record

 

Definitely an intake/exhaust restriction. Why? Valve timing/Cam wrong, valves not opening enough, clogged exhaust, hydraulic lifter problem...

 

Did someone leave a rag in the intake or exhaust? Stranger things have happened.

 

How are the AFR's?

 

 

I'm still running the stock lt1 heads, but since the motor is coming back out I'm going to get some better heads and maybe a hogans intake. Maybe the lifters are bad?

 

 

Valve lash OK?

 

Cam timing OK? Double check intake and exhaust CL on several cylinders, verify overlap and opening and closing points.

 

Piston to valve clearance OK? If the cam got put in wrong you may have tagged the intake valves.

 

jt

 

Timing is on it's mark, car runs and idles good so the valves are fine. It should be making close to 400rwhp without the blower and close to 700 with it.

 

Have you compression tested all cylinders?

 

No I haven't, probably a good start lol.

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So they took the blower off and it put down a incredible 198rwhp.

 

It has to be clogged heck even if you have a BBody LT1 cam it would do better than that. I remember seeing that car and it was healthy just idling so I am voting for blockage on the exhaust side.

 

Good luck

 

PS I put down ~450RWHP with a small cam with iron heads in an 8.5:1 LT1 with 9 psi.

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1) Ignition timing good!

2) Cam timing good!

3) Not the cam specs. The loss of power wouldn't be this extreme for a given boost level and the engine would still make decent power N/A, i.e. with the blower disengaged, which it didn't.

 

Lots of boost pressure in the intake, but all that boost isn't getting the crank. i.e. not flowing freely "through" the engine and "soot" in the intake? I take it this is abnormally heavy exhaust soot, not to be confused with the normal black sometimes oily coating we will see in the intake manifolds of high mileage engines, typically from PCV.

 

Two things come to mind, Rags mentioned one, Darius mentioned the other;

 

1) Critter made a home somewhere between the blower and exhaust tips.

2) Lifters! Are they collapsed not allowing the valves to open adequately, or are they pumped up holding the valves off their seat during operation, causing the "soot" in the intake?

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There's definitely no wildlife living in my exhaust lol. The motor is back out, I'm going to take it back to the place that built it and have them figure out what's going on. The motor still has bone stock lt1 heads and intake. I'm probably going to put a set of afr's on it. Is the lt1 intake worth messing with or should I get a lt4 intake or a hogans?

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There's definitely no wildlife living in my exhaust lol. The motor is back out, I'm going to take it back to the place that built it and have them figure out what's going on. The motor still has bone stock lt1 heads and intake. I'm probably going to put a set of afr's on it. Is the lt1 intake worth messing with or should I get a lt4 intake or a hogans?
If you're going to get different heads (or have the stockers ported) get your stock intake ported as well. There aren't any aftermarket intakes for the LT1 engines and a stock ported intake is better than an LT4 intake.

 

Edit: Edelbrock does make an aftermarket intake, but I haven't seen anything that shows it's any better than the stock one.

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There's definitely no wildlife living in my exhaust lol. The motor is back out, I'm going to take it back to the place that built it and have them figure out what's going on. The motor still has bone stock lt1 heads and intake. I'm probably going to put a set of afr's on it. Is the lt1 intake worth messing with or should I get a lt4 intake or a hogans?

 

A friend's brother has AFR LT4 the big ones and he matches the power of stock iron with 2.02/1.6 valves on a twin turbo running the same boost.

 

Better parts don't always make more power...They are both running ~230 and .570" lift solid cams.

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I didn't remember which engine (or even engine family) you were running Darius, so I didn't realize you should have been making so much more power. Definitely not a cam choice issue!

The lifter problems definitely sound like a a possibility. How long ago was the engine built?

 

like 8-9 years ago, It did sit for quite a while before it was running.

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