merc3065

Here is my current setup...
88 Trans Am with all the creature comforts including A/C and power everything.

88 L98 block, rebuilt stock bottom end
Stock distrib and ignition setup
Have the fiberglass firebird spoiler on it temporarily (my aerowing was eaten from in the inside out yay for GM engineering!)
Alum d/s
3.27 9 bolt rear

Engine Mods

Edelbrock 60859 heads
Edelbrock hiflo TPI base and runners
Accel 24# injectors
SLP TB Airfoil
SLP Cold Air Induction
SLP 1 3/4" headers +y pipe
3" cat into stock 2.75" back to muffler (saving up for a shiny borla system next year)
Smog pump delete
AIR delete (those two above just to clean up clutter and make working easier)
Crane Cams replacement lifters
Comp Cams 1.6 rocker arms for centerbolts
Crane Cams 2032 Powermax camshaft
Comp Cams hardened pushrods 7.195" in length

2600 stall Converter Man torque converter
700R4 with Stage 2 Transgo, bigger 3-4 band, and blue raybestos racing clutches, vette servo and .500" boost valve
Poly bushings all around
Jet Hotchip Stage 2

My first dyno run wasn't very good and the second one wasn't any better...

Heres the sheet


Anyhow, 218rwhp and 280 ftlb tq??

Somethings not working properly here...Is this all because of a lack of a custom chip??

As far as I can tell the whole car is leaned out even at idle. Thing wants to idle at 500-550rpm but fluctuates all over because of the cam (i think?) and the BLMs at idle sit at 145. I checked the timing and set it to 8* advanced and even set the minimum idle air screw and it still wants to idle low.

When driving around BLMs are at 136 and then 134 at WOT.

I checked fuel pressure and with the stock FPR installed at idle its at 38psi, and when it gets up to speed (4500-5000rpm) it reads 32psi. I have a holley AFPR coming tomorrow so i'll be installing that. With the FPR vac line disconnected however, the thing puts out a constant 50psi all the way up to WOT without any trouble. BLMs at idle still are at 142 with the FPR disconnected. But at WOT the BLMs go down to 122 (thats better than before)

I had to replace 3 plug wires as my SLP headers melted through the back ones. So I installed heat shielding over them just for now until I can get some ceramic boot 90* plug wires.

So really, is the only thing holding me back fuel and a properly tuned chip? I was expecting a lot more than 20-30hp over stock numbers at the wheels with all the parts listed above.

Any ideas?

TPI Monte SS

Just looking at the dyno chart makes me seasick. That thing should be smooooooooooooth, not choppy. I believe the fried sparkplug wires and seriously lean condition is killing your power output. Those BLM numbers are very lean. Change the wires, install the AFPR, and toss it on the dyno again to see what your improvement is.

FWIW, I have the Crane 2031 cam in my TPI 305, and on a stock chip I dyno'd 223 hp/ 277 ft/lbs at the wheels. You should be making more power than me, especially since you have an extra 45 cubes.

RednGold86Z

iTrader: (1)

Fuel pressure isn't a function of RPM, it's a function of VACUUM. If you free rev it to 4500-5000, and see 32psi, I'd say that's normal. If at full throttle, and with no vacuum reference at 50, but with vacuum reference at 32, then you have a SERIOUS air intake blockage, but you would be showing 0 hp, not 200+.

If the fuel pressure drops a few PSI from max at full throttle at high rpms, that's normal. If it drops 10, not normal.

A good dyno will have a wideband available. That'll tell you if your fuel supply is sufficient, or if you're too rich or too lean.

Beyond the Hypocrap chip, I'd guess there could be up to 30hp available with tuning, since you've got bigger injectors, and aluminum heads, but are using MAF. But the heads aren't going to likely support much more than that.

merc3065

I know its lean by the gauges used, the visual evidence and what the computer is reading.

The inside of the old manifolds and new headers are whitish grey
The plugs are white
The computer reads 145-150BLM which also indicate a lean condition.
And fuel pressure is nowhere near where it should be, even under load.

I've replaced the plug wires with some NGK ceramic boots to protect from heat.

I have the AFPR to go on this weekend which should allow me to compensate for the lack of fuel.

Im not sure what HP the edelbrock heads are good till, but I know they flow a lot better than the vette aluminum heads do and have bigger intake/exhaust valves as well.

Question tho, what does running MAF have to do with it? It's just as good as SD and is a little more flexible from what i've been reading. I don't see it being a bottleneck till above 300hp?

RednGold86Z

iTrader: (1)

MAF without tuning is a lot closer than MAP without tuning, which reduces the available power with tuning (and I meant ANOTHER 30hp with tuning, not just 30 over stock). Stock power enrichment is conservatively rich, and with larger injectors would be even richer, and with MAF, still rich even with more flow.

But, if you are having a pump supply issue, of course there's more to be had. And if all signs point to trouble, get'r fixed. Something's not right, especially if you can get 50 psi at WOT and high rpms with the vacuum disconnected, but not with it connected, but it doesn't mean a pump or fuel supply issue.

BTW, I have almost the exact same setup sitting on the shelf still. Dunno when I'll be back to install it all, and I'll let you know what it takes to get the tune right. Stock it made about 180 rwhp on our mustang dyno a while back (it always reads pretty low it seems, ZZ4 was at about 220-230 through a th350).

I mean almost exact,
89 350
same stall speed converter
same rear and d.s.
2055 headers
hooker catback
on shelf:
same heads, gasket matched to intake
same cam,
same intake,
delphi 24's
pro mag 1.6's

want to find some AFR 180's instead though. Just a driver, no racing, but saved a TON of money on this adventure.

Rob Wade

Throw that chip in the garbage and fix the fuel pressure shortage and it should come to life.

merc3065

Well heres hoping, I opted to wait until a little later this week to put the AFPR in since the weather has been rainy and very windy. I dont like working under the hood with the breeze making the hood close down on me, and thats with new hood shocks too lol

I'll pull the hypertech one and hope the stock PROM can take over and adjust itself enough to compensate for the cam and bigger injectors until I can get the properly dyno tuned chip done.

Im just hoping that the problem with the setup is just the stock FPR isnt working 100% and that the new AFPR will fix it. If not im going to order up the holley intank fuel pump (255lph) and hope for the best.

brutalform

Im sure the stock chip can do alot better than the one you have now, especially with a MAF.

1MeanZ

iTrader: (9)

I've done similar mods to my LB9 and I am still running the stock chip. With a MAF car you should not need that much tuning. I dyno'd my car when it still had the automatic so my drivetrain loss should be similar to yours. My graph is smooth and very broad. I made my peak hp at 4800-5000 and from 2800-3800 my torque only fluctuated about 30ftlbs. See the sig for modifications my peak numbers are 232rwhp, and 280rwtq.

You should dyno in the neighborhood of 280rwhp. Something else is wrong, your stock chip is not robbing you of that much.

ZZ28ZZ

Just a note. The BLMs at WOT are meaningless since the ECM goes to open loop at WOT. You'll need a wide-band O2 to accurately see your WOT mixture, or a lot of plug reading.

RednGold86Z

iTrader: (1)

BLMs below 128 get ignored. If above, they get used at WOT PE.
If injectors are larger, or fuel pressure higher, that'll make BLMs go down, so yeah, they won't get used.

Best bet is a wideband and a prom burner.

GMTech

I concur. WOT disables Closed Loop operation, but positive fuel trims (anything above 128) are factored in to prevent engine damage.