Best run was 190.7 HP @ 4100RPM and 282.5 TQ @3000 RPM. The engine is running super rich all the way throught the rpm band. I'm still running the reprogrammed 4.9 chip but it's for a stock engine. We think I should be able to get it over 200 HP and 300 TQ with some fuel tuneing, just have to figure out what to use. Any ideas??
We didnt have the exhaust gas analiser hooked up so we didnt get any readings. However we set of every exhaust gas alarm in the cell and there was plenty of black smoke and burning eyes. I want to get some sort of fuel tuneing device and go back with the exhaust gas analiser and see what we can do. I started at 180HP and 170TQ and after 3 runs with advancing timing got it to the 190HP and 282TQ. I'm sure being able to tune the fuel will help a ton.
crzyone wrote:Cudos for going to the dyno, with a tune you might pick up more than 10hp.
That torque curve is brutal, starts falling after 3200rpm... ouch.
The first run the torque curve was flat with a max of 270 and didnt start falling off until 4500rpm or so. After we messed around with the ignition timing it started falling off more. The engine is really out of tune.
I only have the print outs from the best run which was run 3. I really want to get some sort of fuel managment on this thing and try to tune it a bit. They didnt have the wideband in the building we were at. It will be hooked up when we run it again (maybe 2 weeks). I also removed my restrictive filter/intake setup on the last run. I'm going to weld up a nice 4" intake tube with a huge filter on it. I'll have the filter by the stock air inlet. Maybe I should finish wireing up the nitrous kit and get the bottle filled before my next visit too.
I also still want to make some headders. I have axcess to a water jet, tubeing bender and tig welder. The nice thing now is I will know how much power they add when I do it. :thumbleft:
Any ideas on what I should get to tune this thing? AFC??
It all depends on how you drive it. If your into the throttle hard all the time is ok. If you drive it easy it will load up on fuel really bad and eventully start to missfire until you romp on it to clear it out. Same deal on the highway.
crzyone wrote:Cudos for going to the dyno, with a tune you might pick up more than 10hp.
That torque curve is brutal, starts falling after 3200rpm... ouch.
The first run the torque curve was flat with a max of 270 and didnt start falling off until 4500rpm or so. After we messed around with the ignition timing it started falling off more. The engine is really out of tune.
Thanks for posting about your dyno. Hardly anyone does that for 4.9's and consequently certain persons here try to give them a bad rep. You can't expect too much from an engine that was only rated 200 HP from the factory. You're doing well with yours, though. As Shaun said, you're significantly over 200 crank horsepower. Do you have an auto or manual? What other mods do you have?
Yeah, you need some tuning work all over the place. I believe RockCrawl has run 4.9's on 7730's and has a program that would work for that. I'm not sure of the extent of tuning capacity that is available for the stock computer.
I'm running the Isuzu 5 speed. Mods are ported heads, ported Allante intake (if thats a mod?), Delta reground camshaft. I've got a MSD Coil, distributor cap and plug wires but dont know if those are any better than stock either. I want to get something that I am able to tune myself while at the dyno. I'm also planning forced induction and being able to tune it myself would defenatly be good for that.
Forgot, I have nitrous as well but it was not used at the dyno. I need to get the bottle filled and reconnect the power switch. Maybe I'll have that set to go next time I'm at the dyno. :thumbleft:
Well other then a stand alone you are sort of limited one what you can use to tune while on the dyno. I think there are emulators or something that you can buy and plug into your computer and tune, then after you tune you need to burn the chip. So its some equipment to buy o course and then the learning curve of how to use it and then save it and then burn the chip.
You can try to run a few more degrees of timing, bring your fuel pressure down a few psi, and run 1 range hotter plug. That would help burn off more of that fuel so it isn't so rich. However you would have to take all those away if you were to run nitrous on it.
An afc might be your best bet. THe learning curve on it is about 5 minutes and it isnt' hard to wire in. Its sort of a bandaid I guess but for around $200 its not a bad alternative.
Or just have pbj burn you a chip with some fuel taken out at part throttle and wot . Not sure how well that will work though.
To really know how rich you are though you need to get the wideband on it. You can't guess on how much to take out unless you know your a/f curve.
Shaun41178(2) wrote:Well other then a stand alone you are sort of limited one what you can use to tune while on the dyno. I think there are emulators or something that you can buy and plug into your computer and tune, then after you tune you need to burn the chip. So its some equipment to buy o course and then the learning curve of how to use it and then save it and then burn the chip.
The emulator makes a GM computer tune on the fly, just like an aftermarket computer. A laptop PC is required, of course. IE, you can install the emulator, tune on the dyno, drive home w/ emulator, burn chip, replace emulator w/ chip and drive around normally. I think that one version of emulator can be left in the car and just unplugged from the tuning PC.
Fast88Fiero wrote:I'm running the Isuzu 5 speed. Mods are ported heads, ported Allante intake (if thats a mod?), Delta reground camshaft. I've got a MSD Coil, distributor cap and plug wires but dont know if those are any better than stock either. I want to get something that I am able to tune myself while at the dyno. I'm also planning forced induction and being able to tune it myself would defenatly be good for that.
Watch out for 2nd gear. Hasn't someone on the Cadero list (George Ryan?) gone through 4 or 5 Isuzus behind his 4.9?
Is porting the Allante intake adviseable? I have one and from looking at it the runner cross section stays mostly the same for the length of the runner, so by enlarging the manifold, you're making velocity inconsistent along the length of the runner and may be sacrificing power.
I've been wanting to try Allante intake + tuned long tube headers & other bolt on mods just to see how much power can be gotten from a 4.9 "easily". Even RockCrawl's modded engine that ran a 13.2 was still using the factory cast log manifolds. W/ headers that car could probably crack 12's.
I'm on my 6th or 7th Isuzu. This is my 2nd one behind the 4.9, the others died behind my old V6. Every time it's 2nd gear. Next time it dies I'm swapping in a Getrag.
I got to thinking about it and it was the stock 4.9 intake I ported. I did not port the Allante intake because it had bigger ports already. So it's just the heads that are ported.
Figured out some of my problems today! Had a bad wire to the TPS and MAP sensors, they had too much resistance. Replaced the wires and it started running better. I also found out that I'm only getting about 11.8V to the fuel pump due to excessive resistance in the fuel pump relay. I'm installing a new relay tomorrow. :thumbleft:
Fast88Fiero wrote:Figured out some of my problems today! Had a bad wire to the TPS and MAP sensors, they had too much resistance. Replaced the wires and it started running better. I also found out that I'm only getting about 11.8V to the fuel pump due to excessive resistance in the fuel pump relay. I'm installing a new relay tomorrow. :thumbleft:
Always good to figure out problems! Nice numbers also... When you get good 14 volts to the fuel pump, you're gonna run even richer though.
