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HybridZ

Been holding out on you guys :-)


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Wow, a really sobering night and I have some gremlins to work out...

Not sure what is going on, but 6500 rpm's, car hiccups and I have to get out of it...can't find anything wrong in the datalog, other than a drop in timing from 21* to 15* and a lean spike due to the hiccup... 

It struggled to pull under load and trapped only 114 mph @ 8psi  :-(

I'll get it figured out, but have to post the bad with the good...

It can only get better from here <sigh>

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Thanks John/Jerry, I plan on being there in Oct in Reynolds. It depends solely on my work schedule. I may still be in the training bubble, and if so, then I have no control of my days off...

Hi Pete, I was making somewhere between 750-800 rwhp with the 2JZ according to my 1/4 mile time and weight...

Daz, here are a couple more pics, one showing the drivers side, and the other from the front...The full 3" exhaust exits the stock location in the rear. The 4" exhaust dump exits in front of the pass side tire (has a removable cap v-banded on for street use)

Thanks for the pics ! I really like the design of it and may change what I have to yours !

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  • 2 months later...
  • 3 weeks later...

No appreciable updates. Car runs great into boost. I can feel the spool up, it starts pulling HARD, and then kind of noses over and feels like it struggles through the rest of the RPM range. Datalog doesn't show anything strange (timing is stable, a/f ratio, boost, etc all normal). I replaced the LS1 truck coils with a new set of truck coils, with no change. Next i am going to put a trigger wheel and crank sensor pick up on the crankshaft damper, eliminating any potential problem with the stock pickup (whenever I have the time). Winter is coming, and I am buried under other projects, so I don't expect much progress until the spring. Meanwhile, I'll continue driving it around on nice days, until I can figure out the loss/lack of power, then I'll take it back to the track and get some numbers  out of it...

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Sure sounds like valve float.  Likely are using hydraulic roller lifters and weak springs.  The timing backing off from 21 to 15 degrees sounds like too much roll back.  Sounds like a combination of the two.  If you want to spin it beyond 6500 RPM will need to go to solid roller lifter and camshaft.

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Sure sounds like valve float.  Likely are using hydraulic roller lifters and weak springs.  The timing backing off from 21 to 15 degrees sounds like too much roll back.  Sounds like a combination of the two.  If you want to spin it beyond 6500 RPM will need to go to solid roller lifter and camshaft.

 

Respectfully, no you don't.

 

I have several local friends that have hydraulic roller LS engines that turn 8200 rpm every weekend at the strip. My last combo saw 7000 every time I drove it, zero issues. The above mentioned engines were NA and Nitrous, so a fair amount of cylinder pressure.

 

What springs are you using? The Brian Tooley racing springs seem to be about the best thing on the market as far as a stock- replacement go.

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Respectfully, no you don't.

 

I have several local friends that have hydraulic roller LS engines that turn 8200 rpm every weekend at the strip. My last combo saw 7000 every time I drove it, zero issues. The above mentioned engines were NA and Nitrous, so a fair amount of cylinder pressure.

 

What springs are you using? The Brian Tooley racing springs seem to be about the best thing on the market as far as a stock- replacement go.

Mike, what was your last combo?  Gen I or Gen III?  V8dats has a good suggestion to the problem about exhaust restriction.  Some of the discussed items may be the fault.

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Thanks for all the replies guys...

I am using a set of Comp Cams Beehive springs with LS6 lifters and LS2 lifter trays. The springs are supposed to be good for .600 lift... My cam is .595 lift...

The power struggle begins around 4700 rpm's, after the turbo is spooled. It's no longer breaking up, after i reduced the dwell on the coils (MS3 EMS). It's  just struggling to make rpm's. I've added 4 degrees of timing, and then backed off 4 degrees of timing with no change. I have been in Canada for training the last few weeks, so haven't had any time to play with it. Once I get my ox out of the ditch, I'll install a trigger wheel on the front of the crank pulley and eliminate any crank sensor issues. 

As far as the exhaust choking it down, maybe a little with the full exhaust, but it acts the same even when the 4" dump is connected.

Last combo was 2JZGTE, this is my first V8 turbo

Again, I appreciate the suggestions, and I'll keep the updates coming as I work through it.

Mike

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I still vote for a look at the springs. Have you tried turning the boost down to see what it does? I can just about guarantee you those springs were never meant to deal with the cylinder pressures you're creating.

 

I'm by far no expert on this, just a top down view.

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What springs are you using? The Brian Tooley racing springs seem to be about the best thing on the market as far as a stock- replacement go.

That is what I am running, very nice double spring, good to .675 lift. great bang for your buck investment. Good luck with your new set up!

 

Mike

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Thanks for the recommendations. I had it out today and was able to do some spirited back road driving... At 1/4 throttle, the fall off in power is minor, in fact, the car feels significantly faster at 1/4 throttle than at 1/2 or even full throttle... You guys may be on the right track to look at the springs. If the springs arent strong enough to pull the valves back into place quickly with the additional boost pressure on the back side of the valve (essentially floating the valves open longer than they should), then it stands to reason it could cause the symptoms I am getting...

BTW, Plug gap is .025, I doubt I am blowing out spark, but again a good suggestion.

Edited by Z-Gad
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  • 2 weeks later...

More learning curve for me...

Bought a set of Lunati dual valve springs to install, as well as a recommended Proform LS1 "head on engine" valve spring compressor. Well, I found that my aftermarket Warhawk heads have more casting material and will not allow the use of the special $70 LS1 valve spring compressor I bought. Then, after 2 days of trying to support the valves with 2 different types of rope, and then some rubber vacuum line (always worked great on the ole L-series), and then rope again, I finally caved and hooked up the compressed air to hold up the valves in the seats. Wish I would've done that in the beginning. So I remove the keepers and springs from the #1 cylinder, pull the valve seals and spring seat, only to find my dual valve spring seats will not fit my heads either. The ID of the spring seat is too small for the OD of the valve guide. Apparently the Beehive springs use a wider ID diameter seat, so all of the guides would have to be machined to allow a dual valve spring to be used... GRRRR, another $250 wasted on the valve spring kit... So, i ordered yet another set of valve springs today ... PAC 1519's 

Can't do anything with it until Friday, so I'll have to stew until then  <sigh>

If anyone is interested in a slightly used valve spring tool and a new set of .660 lift Lunati dual valve springs, I have a for sale ad on LS1tech  I'll offer an additional 10% to any HybridZ'ers. I hate wasting money... 

Edited by Z-Gad
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