solocus

iTrader: (8)

Ok, so I need some advice or comments on my situation. Dyno’d the car with just a lid and Holly Powershot filter just over a year ago and put down 308 rwhp 331 rwtq on a DynoJet. Over the winter made the following Mods:

Kooks 1-3/4 headers
Kooks ORY (no cats)
Jantzer Ported TB
160 degree thermostat
NGK tr-55
MSD wires
Free Ram Air Mod (cut lower Air Box)
Paper Air Filter (pulled the Holly Powershot)
Tune (remove Cags, Cats, Fan Temp to 160 degrees, and “98 octane tune”

So Saturday I go to another shop and get it dyno’d also on a DynoJet. First run was “dangerously lean” put down 307 rwhp and 319 rwtq. The guy dynoing it used HP Tuners to adjust my A/F to about 13.6 across RPM range and my numbers were 313 rwhp and 333 rwtq. He did this by just adjusting the fuel tables.

My thoughts, WTF $1000 plus and almost no gain! I guess I could have got major heat manifold heat soak from the FRA. Maybe a filter does make a huge difference. Could TPS on TB be jacked up? Do I need a professional Dyno tune? WTF

foff667

iTrader: (2)

different dyno's different results...going "dangerously lean" on the stock tune sounds more like a mechanical issue then anything since the stock tune commands ~11.5:1 at wot in most calibrations...also 13.6:1 on a dyno will generally run slightly leaner on the street so its a possibility the tune is still off.

solocus

iTrader: (8)

It had a tune prior so it wasn't really a stock tune. I'll have to post graphs when i get home tonight to make sure i have my A/F numbers correct.

foff667

iTrader: (2)

either or...some people have said form one dyno to the next there have been differences of up to 20hp...you'd really need a true before & after on the same dyno the same day to compare accuratly.

niphilli

IMHO 13.6 is not safe (Lean). Try running a diagnostic software against it. Look for knock, A/F (O2), timing, throttle position sensor...etc.

Mike TexaSS

iTrader: (2)

Add some fuel.

TTPMatt

iTrader: (18)

I would look at false knock possibly. If the y-pipe pieces were not installed correctly it could be banging the floorboard. Bad gas... lots of things it could be. That combination I usually get at least 340+ out of even on a "non-dyno queen" car.

you2slo

You run 98 octane in your bolt on car? You don't have a catback? You may have some constriction there.

silverTA2002

iTrader: (1)

Like they said 13.6 is still too lean.

What's funny is that at the dyno day I went to this weekend, the shop guys kept telling the LS1 cars that they should shoot for 13.5 to 1.

WRONG!!

They should shoot for 12.5 to 12.8 to 1 on a dyno wideband for a relatively safe tune with good power.

silverTA2002

iTrader: (1)

Yeah, 98 octane is a big no no for a stock internally car.

You'll lose power.

The higher the octane the LESS combustible the fuel is. Unless you're running seriously high compression or tons of boost...... stick to 93 octane.

solocus

iTrader: (8)

My bad, I meant 93 octane. My car ran smooth and sounded good, he had HP Tuners hooked up so I would have thought he would have caught detonation, he did catch detonation on a few other cars being dyno'd that day. It was hot in the shop, I saw 101 on one of his computer screens and i think a humidity of 30%. I thought this was all compensated for with SAE numbers.

I'm ditching the FRA and going back to the Holly air filter. There does seem to be some argument for manifold heat soak out there. Well the consensus seems to be add more fuel. so that will definately be on my list!

Mike

SVT THIS

iTrader: (27)

Dyno numbers mean jack ****. What were your track times before and after? Did you improve? That's all I would worry about. You don't race people on the dyno...

cantdrv65

iTrader: (3)

13.6 is DEFFINITELY too lean...Id take it too someone who knows what they are doing.

solocus

iTrader: (8)

Here are both graphs.
Could the temp 102 degrees almost be killing me?

First one with Lid and Holly filter



Second with kooks headers and ORY, ported TB, 160 thermo, FRA, Tr55 MSD Wires, paper filter

silverTA2002

iTrader: (1)

What's interesting is on your first dyno, you cut off right when the HP is about to peak. I'd bet you'd even make slightly more power if you'd kept in it.

solocus

iTrader: (8)

Heh, no doubt. I guess the guy didn't want to push it and I knew no better at that time.

98redorangeta

iTrader: (10)

You definatly need to be a little more rich 13.6 to 1 isnt a good afr 13.0 would be better. Check the usual things over too if you can compression, fuel pressure (under load not at idel), plug gap just to make sure things are still in order.

NickcZ28

iTrader: (9)

that sucks i slapped a set of stepped headers "kooks" and gained about 45rwhp

Benjamin Russick

iTrader: (1)

The Holley filter is worth 0-2 rwhp, so that doesn't sound like the problem. I would look for knock or an installation issue.

Louie83

iTrader: (3)

Actually they use a thing called "physics" to test how much power your car is putting on the pavement.