amdoverclocker

This spring I redid the top end of my 07Z. Here is what I replaced:

stock cam with Katech K501
C5R timing chain
caddliac racing lifters
7.775 pushrods
new stock rockers
new stock exhaust valves
stock intake valves
Titanium valve spring retainer
PSI High Lift Valve Springs
katech spring Seat for bronze guides
CHE bronze guides

I also milled the heads .030. I took it to my tuner and he got it running well but its not perfect. It has some idle hunt issues and he said I had to run 93 octane but the timing still isn't above 20. I've read plenty of threads where people are running this setup easily on 93 octane. Is my tuner a little dumb when it comes to the LS7 or am I missing something? Running 93 in town is fine but now that I want to take it on a road trip, it makes thinks much more difficult. I've been thinking about switching to e85 but there are only 3 e85 stations in KC(home). Thanks!

Big Les

You don't need E85 for this setup and you know that as well. Sounds like you need a new tuner.

blacktavert

You could set it up with Dsteck's flexfuel setup so you can 93 or E85 or any combination of the two
Only way I would run E85

amdoverclocker

Yeah I was reading more on this stuff right before you posted. I'm going to give them a call tomorrow. St Louis is only about 250 miles from here so I'd just assume drive down there and have them tune it as well. We'll see what they say. Thanks!

BOTTLE FEDvette

get a new tuner...steck seems to do a great job.

Unreal

Don't get hung up on timing. I wouldn't be concerned with how much it takes, but the power it makes and how it drives.

Twistedpixels

Do you know the dynamic compression right now? That could be a big reason why. I had the same issue even on 91 with torco when my dynamic was 8.77:1 Lowered it to 8.55 and it took 2 degrees more and made more torque across the board. Before it was maxed at 20 and then took 22 but on the street had to back it to 20. The street wins every time in the timing and fuel wars.

Michael_D

What exactly do you think is not correct? I'm having difficulties trying to interpret what you think is not right. And what spark table are you referring to? There's a bunch. Idle hunt.....easy to fix.

amdoverclocker

My issues are idle hunt, anything near 2k the drive ability is down the toilet and the power doesn't appear to be consistent. If the idle hunt issue is easy to fix, why couldn't the last guy get it right? Stuff like that just doesn't give me a good feeling about his ability.

According to cr133r worksheet I'm at 8.88 DCR.

I called dsteck(dan? cant remember) and got more info on the flex fuel conversion.

DSteck

Dave.

vertC6

I just ordered Dave's flex fuel sensor this week!

amdoverclocker

Yep that's the guy!

Michael_D

Well it sounds like you need someone else to look at this, as there's no reason for it to be behaving that bad. That cam isn't all that aggressive. But do keep in mind, it will not feel as snappy under about 2500 rpm as the OE camshaft did.

You could call Katech. They have a pretty damn good tuner now, and he's very familiar with that camshaft. Or, just let Dave have a go at it, seeing how he's in your neighborhood. He is a ornery SOB, but knows his shitt. Bring him a six pack of one of the fancy micro brews.

silverarrow

My experience with a Halltech Tune by Jim Hall is exceeding all my expectations. Give him a call I believe he can fix your situation so it will run right. Just one mans 2 cents

The_Raging_Bull

If your warranty is over, just use Torco to achieve 93+ octane. It requires half a quart per 16 gallons to be about 93.5 to 94 octane. The key ingredient is MMT, a gasoline additive that acts as a octane booster while lubricating the valve guides..just like tetra-ethyl lead (TEL) used to. It's not illegal as Ethyl Corporation beat the EPA fie times in court, but (my guess from having a brother who as an executive VP at Ethyl - and in charge of their MMT development programs) - the govt and the big three probably colluded to ban MMT use in the states with a warranty; since it does void your warranty, and is easy to detect either by the orangish colored deposits it would leave in the runners after the hot gases escape the engine on their way to the exhaust..or via atomic absorption/ICP spectroscopy of the deposits...manganese is a positive test.

That said, MMT is used successfully in many countries for just this reason, the closest is Canada - which is why Chevy doesn't want you buying your Vette in the US if you're a Canuck; and then buying gas there, Vettes in Canada would necessarily allow the use of gas with MMT - since they use it in their gas.

Frans96ss

Where are you located?

Hib Halverson

I'm a little confused by one thing in the OP.

It says "Stock cam with Katech 501".

So...do you have a stock camshaft or do you have the Katech 501?

The problem with some "tuners" is they can do a reasonably good job with the "basics" such as WOT fuel and spark but some of these guys don't know much about how to properly tune for good idle and part throttle drivabilty and, also, some people who are consumers of tuning services don't want to pay the cost of good part throttle tuning work.

That said, the 501, If that's what you have, likely has a lot more overlap than did the stock cam and overlap is want can make tuning at idle a real challenge and no "tuner" will be able to fix it but a good aftermarket calibrator (ie: a real tuner) could likely have success.

Also, some of these "tuners" may be good at changing spark tables and fuel tables but they really don't understand the special needs of the LS7. For instance, a lot of guys will see GMs rich at WOT cal and lean it out. Unfortunately, that's the kiss of death for long term exhaust valve and seat durability unless you're running a really expensive Inconel or titanium exhaust.

As for milling .030...that's quite a bit. In some parts of the torque curve you're really going to need some good gasoline. Also, if this is a car you are going to use on long trips into places where 93-oct fuel is not available don't let your "tuner" commit the sin of copying all the high octane spark data into the low octane spark cal.

Lastly on E85 you can't just "switch to E85" and have good durability unless your car has an E85 fuel system. Also, you need different injectors and a different calibration to run E85. Lastly know that from a consistency standpoint, most E85 that comes out of pumps at gas stations is really crappy. It can be anything from E60 or so to E85 so you really need an engine with an ethanol sensor, the right ECM and good calibration.

That said, the racing E85 sold by many race gas vendors will be exactly 85% ethanol and 15% gasoline.

The_Raging_Bull

Hib's exactly right; we have to deal with this in Oklahoma all the time...many gas stations may say E85- but you need to test the gas to make sure. During various seasons in Oklahoma they sell anywhere from E60 to E85; and it'll ruin your day to spend all that money and STILL not have E85 in your tank. Here's the tester at JEGS:

http://www.jegs.com/p/Holley/Holley-...83596/10002/-1

Basically if you get lower than E85 - then you're having to boost octane with Torco or the like; as your tune REQUIRES E85 - assuming you've done larger injectors and a boost-a-pump, and a flex fuel system complete with that ethanol sensor to make sure you're delivering the extra 30% fuel and the 105 octane that an E85 tune requires and a build where the compression ratio is not as high as a full on E85 system would let you run. I recall Jason Harding at Katech talking 13:1 with E85.

A friend of mine here in Tulsa (we're both in the Tulsa Vette Set) gets around all this by taking a truck with a couple of 55 gallon barrels to Oklahoma City and buying 110 gallons of real E85 from the station there that has REAL E85 all year long; which is a PITA.

Unreal

That is the whole point of flex fuel. 0% to 100% meth, car doesn't care. Tune is adjusted. e60, e90, e30, car don't care, it adjust for it.

amdoverclocker

I'll admit I am a flex fuel novice but I thought that was the point of dsteck's kit. It will detect what fuel is in the line and adjust for it.