taking the old girl to get put on dyno and tuned this weekend!! kind of nervous. this will be the 1st time i ever had a car on the dyno. the guy i bought her from had her on the dyno but would not rev over 4300rpm she was running out of fuel, however was pushing 540hp at this rpm. he added a 2nd internal fuel pump but never had it put on the dyno or tuned. needless to say she is running pretty rough right now! the trans is a 700r4 with 2-2500 stall and doesnt seem to be shifting very well and at a constant speed i can watch the tach vary 2-300rpm. am i hoping for to much to think that this dyno and tune can fix my problems?

 

What are the mods? What are the specific problems?

To make 540HP at the rear wheels (approx 650HP at the fylwheel, thru an auto trans), at 4,300RPM, it would have to be making 800 lb-ft of torque. That's about what my 381 stroker makes with a 300 shot of nitrous.

Obviously it has a power adder. So you need to provide the details on the engine build, in order for anyone to even take a wild guess at an answer?

 

Alot can happen with a good tune but hard to say as it would depend how far off your tune is now. In my opinion once you get over 500wheel hp the tune is often critical and if its not spot on can foul plugs and struggle to continue to run well. My dad has a subaru and he has it pumped up so much very few people can get a good tune on it and now its pushing so much he cant keep the heads from lifting. If it were me I would change ur plugs and anything the tuner may recomend. You might have to cut our tune short and find your problem if its not in the tune. Thats alot of power what you got in it? Do you have any scan and log tools?

 

please look at mods in my garage.

 

Can you give further details...cam, tune, etc?

 

ModificationsExterior Red with Black hockey sticks


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Interior stock, besides buttons for N.O.S.


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In-Car Entertainment and Electronics Pioneer detachable cd player with 1000w amp


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Performance Upgrades 385 CI
4 Bolt Mains/ ARP Bolt/Studs/
Balance Eagle Rotating Assy
Super Damper 7.5
Ported Heads
Comp Hardened Push Rods
Headers
Borla Cat Back Exhaust
72lbs.Injectors
Fast Computer Fuel Management
DI-SC Super Charge Kit (14. Ibs Pulleys)
Dual Intercoolers
2 Stage of Nos
Bottle Warmer
Dual Fuel Pumps

 

not really sure what you mean by tune but hear is some cam info

Comp Cam Grind#lt1 292XFI

gross valve lift is .584-intake and .579 Exhaust

lobe lift intake-.3660 exhaust .3630

duration @.050 intake 242 exhaust 248

 

thanks Lt1son never thought of that

 

What size injectors?...

 

I still say look at your plugs. You have quite a setup and to get it all working together may be a challenge as obviously the previous owner didnt get her dialed in. Are you running a standalone management system or are you using the stock pcm? Again describe what its doing?

 

The way to handle this correctly is to set up a "signature" with at least basic info about the vehicle -year, model, engine, trans and major mods. That way people can help you without guessing where to find the info.

 

72# injectors

 

good idea! thank you sir!!

 

i know the fuel is handled with Fast and i believe the rest is handled with the stock pcm. it is running very rough and rich. i'm hoping i didnt get myself in to to much of a nightmare here. the car has alot of potential i'm just not to familiar with it yet. i'm hoping the dyno and tune will head me in a good direction.

 

I was assuming you were running rich and thats why I say check and or replace plugs. I would also see what plugs your running as with the n2o and supercharger you may need to change them more often and see if your running the right heat range and all that. I am also assuming the last owner didnt tune on it after the fuel pump addition(could be wrong). I figure it was left rich until some of the bugs were worked out and probably will find the plugs show you that. Im more familiar with high hp import turbo builds and the other thought I have is the sc may not really be designed for 14 pounds of boost. Im not sure if boost leaks become an issue or not. Might be easier to dial in with less boost and then progress up . A good tuner becomes pretty important on some builds. Dont be discouraged but look for things that may add dependability with your setup. My dad continues to not do that and he is dependant upon two tuners one on each coast and pretty much no one else can dial him in. But he cant turn up the boost to what its capable of without lifting the head. The tune can make a huge difference for him though. Im assuming your build has crossed thresholds were you dont get what you want at all the perameters and make the compromises that suit you. My other concern is if once you get the power in your setup if the drivetrain will handle it. Might consider that as well cuz if its not built to handle the power you very well may want to run less boost and therefore tune for less(get the new pulley on before tune) reguardless keep this in mind as far as problems go having a car with so much potential and struggling to get it may seem horrible and brain racking but its an awesome problem to be fortunate to have so be thankful while you work through it all and it wont hurt so bad if things dont fall into place.