- Mar 30, 2014
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ok.....for one,im running lean cus im pushing more air correct,but im also producing the same small amount of fuel with the 19lb injectors?? someone correct me if im wrong,but i do beleive fuel and the stock maf is my problem
New Heads And Same Inlet Tract. No New Power? Wtf??? O_o
- Thread starter skarrphace 5.O
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If the cylinder heads you put on can flow more air, but everything before the cylinder heads is the same as before, then the new better flowing cylinder heads are not going to be able to make more power, because there is no more air available than with the old cylinder heads. The engine is nothing more than an air pump. If the amount of available air does not change, then the engine can not possibly pump more air, so the power remains the same.
Step 1.) Go back and list all the mods in one place at one time. Chasing around to find what you have and haven't done is bound to create misunderstanding.
List:
Intake manifold - make & model.
MAF - make & size.
Heads - make model valve size port volume and flow data if available.
Throttle body - make and size.
Cam -make & model, valve lift and duration.
Stock or aftermarket ignition, if aftermarket, make & model.
etc., etc.
Once you have posted a complete list, then we can come to some informed conclusions.
Step 2.) Do a cylinder balance test and dump the codes to make sure you didn't break something during the installation.
Cylinder balance test: use this to find dead or weak cylinders:
Revised 25 March 2012 to add necessity allowing the KOEO tests to finish before starting the engine and the need for a properly functioning IAB/IAC to run the cylinder balance test.
The computer has a cylinder balance test that helps locate cylinders with low power output. You’ll need to dump the codes out of the computer and make sure that you have the A/C off, clutch depressed to the floor and the transmission in neutral. Fail to do this and you can’t do the engine running dump codes test that allows you to do the cylinder balance test.
Here's the way to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great. You watch the flashing test lamp or Check Engine Light and count the flashes.
Be sure to turn off the A/C clutch depressed to the floor, and put the transmission in neutral when dumping the codes. Fail to do this and you will generate a code 67 and not be able to dump the Engine Running codes.
Here's how to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great. You watch the flashing test lamp or Check Engine Light and count the flashes.
If your car is an 86-88 stang, you'll have to use the test lamp or voltmeter method. There is no functional check engine light on the 86-88's except possibly the Cali Mass Air cars.
The STI has a gray connector shell and a white/red wire. It comes from the same bundle of wires as the self test connector.
89 through 95 cars have a working Check Engine light. Watch it instead of using a test lamp.
The STI has a gray connector shell and a white/red wire. It comes from the same bundle of wires as the self test connector.
WARNING!!! There is a single dark brown connector with a black/orange wire. It is the 12 volt power to the under the hood light. Do not jumper it to the computer test connector. If you do, you will damage the computer.
What to expect:
You should get a code 11 (two single flashes in succession). This says that the computer's internal workings are OK, and that the wiring to put the computer into diagnostic mode is good. No code 11 and you have some wiring problems. This is crucial: the same wire that provides the ground to dump the codes provides signal ground for the TPS, EGR, ACT and Map/Baro sensors. If it fails, you will have poor performance, economy and drivability problems
Some codes have different answers if the engine is running from the answers that it has when the engine isn't running. It helps a lot to know if you had the engine running when you ran the test.
Dumping the Engine Running codes: The procedure is the same, you start the engine with the test jumper in place. Be sure the A/C is off, clutch depressed to the floor and the transmission is in neutral. You'll get an 11, then a 4 and the engine will speed up to do the EGR test. After the engine speed decreases back to idle, it will dump the engine running codes.
Trouble codes are either 2 digit or 3 digit, there are no cars that use both 2 digit codes and 3 digit codes.
Cylinder balance test
If you have idle or IAC/IAB problems and the engine will not idle on its own without mechanically adjusting the base idle speed above 625-750 RPM, this test will fail with random cylinders pointed out every time it runs. The IAC/IAB must be capable of controlling the engine speed to run in the 1400-1600 RPM range. Playing with the base idle speed by adjusting it upwards will not work, the computer has to be able to control the engine speed using the IAC/IAB.
Warm the car's engine up to normal operating temperature. Use a jumper wire or paper clip to put the computer into test mode. Let it finish the Key On Engine Off (KOEO) code dump. Start the engine and let it go through the normal diagnostic tests, then quickly press the throttle to the floor. Remember to keep the clutch pedal (5 speed) depressed to the floor during the test. The engine RPM should exceed 2500 RPM's for a brief second. The engine RPM's will increase to about 1450-1600 RPM and hold steady. The engine will shut off power to each injector, one at a time. When it has sequenced through all 8 injectors, it will flash 9 for everything OK, or the number of the failing cylinder such as 2 for cylinder #2. Quickly pressing the throttle again up to 2500 RPM’s will cause the test to re-run with smaller qualifying figures.
Do it a third time, and if the same cylinder shows up, the cylinder is weak and isn’t putting out power like it should. See the Chilton’s Shop manual for the complete test procedure
Do a compression test on all the cylinders.
Take special note of any cylinder that shows up as weak in the cylinder balance test. Low compression on one of these cylinders rules out the injectors as being the most likely cause of the problem. Look at cylinders that fail the cylinder balance test but have good compression. These cylinders either have a bad injector, bad spark plug or spark plug wire. Move the wire and then the spark plug to another cylinder and run the cylinder balance test again. If it follows the moved wire or spark plug, you have found the problem. If the same cylinder fails the test again, the injector is bad. If different cylinders fail the cylinder balance test, you have ignition problems or wiring problems in the 10 pin black & white electrical connectors located by the EGR.
How to do a compression test:
Only use a compression tester with a screw in adapter for the spark plug hole. The other type leaks too much to get an accurate reading. Your local auto parts store may have a compression tester to rent/loan. If you do mechanic work on your own car on a regular basis, it would be a good tool to add to your collection.
With the engine warmed up, remove all spark plugs and prop the throttle wide open with a plastic screwdriver handle between the throttle butterfly and the throttle housing. Crank the engine until it the gage reading stops increasing. On a cold engine, it will be hard to tell what's good & what's not. Some of the recent posts have numbers ranging from 140-170 PSI. If the compression is low, squirt some oil in the cylinder and do it again – if it comes up, the rings are worn. There should be no more than 10% difference between cylinders. Use a blow down leak test (puts compressed air inside cylinders) on cylinders that have more than 10% difference.
I generally use a big screwdriver handle stuck in the TB between the butterfly and the TB to prop the throttle open. The plastic is soft enough that it won't damage anything and won't get sucked down the intake either.
A battery charger (not the trickle type) is a good thing to have if you haven't driven the car lately or if you have any doubts about the battery's health. Connect it up while you are cranking the engine and it will help keep the starter cranking at a consistent speed from the first cylinder tested to the last cylinder.
See the link to my site for details on how to build your own blow down type compression tester.
- Mar 30, 2014
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prior to installing the gt40x heads,i already had a e303 mild cam,full valve body shift kit but stockAOD internal trans gears,no smog,a/c delete,off road xpipe,stock lifters,stock rockers,65mm TB,stock maf,stock distributor,stock 19lb injectors,then in came the gt40x heads,cobra upper lower intake,shorty headers,9mm wires,aftermarket spark plugs,and it has never ever been tuned
whats your timing set at?....you need to upgrade some stuff....fuel,throttle body maybe,dyno tune helps to tie it all together...but i would think you should have felt somthing?...
ill stay out for now....
these guys will set you strait though im sure...
ill stay out for now....
these guys will set you strait though im sure...
I mean there's guys that are running 24lb injectors but you don't need anything bigger then that you don't need a dyno tune with that small setup it's ideal but not needed a calibrated maf and matching injectors will get you close enough.
thats what i was thinking?.... throttle body should be ok also?,"maybe" bigger....should feel somthing though?....i put upper and lower intake headers,and 65mm tb long time ago on my stocker and it felt way better...
- Mar 30, 2014
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thanks for all of your help,i was leaning toward the 24lb injectors and 75mm maf....i will keep yall posted
- Mar 30, 2014
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I didn't see what size throttle body you were running but larger with matching spacer would be good as well.
When you're able, get a better cam with more lift. It will make better use of all the inlet restrictions you're eliminating.
When you're able, get a better cam with more lift. It will make better use of all the inlet restrictions you're eliminating.
- Mar 30, 2014
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65mm tb,i cant do a bigger cam with a AOD trans cus i dont have a stall converter,thats why i have the e303 cam which if im not mistaken is the most mild cam for that motor
- Mar 30, 2014
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I would get a 70mm throttle body with that 75mm MAF also I didn't see or pay attention still 1.6 roller rockers? Or did you upgrade those to 1.7? Being it's an 303 cam maybe you can achieve more lift by getting 1.7 roller rockers
- Mar 30, 2014
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ok,and i initially installed 1.6 rollers but they came with crappy aluminum pedestal mounts......so naturally the mounts cracked when i torqued the rockers down,thats why im back to the stock rockers
Don't think I'd bother with the larger throttle body at this point. The Cobra inake and GT40X heads aren't moving tremendous amounts of air on a 302, so going from a 65mm to a 70mm isn't really going to do anything but empty your wallet. Spend that money on a MAF Meter upgrade. Your stock unit is only 55mm. Stepping up to a PRO-M 75mm bullet would certainly benefit you at this point...and if you're going to go that far, you might as will pick up a set of 24lb/hr injectors as well. You should be able to run some additional timing with your GT40X's over the stock E7TE's as aluminum heads less susceptible to detonation.
Picking up a set of aftermarket headers will really help you out too. The stocker are crushed down to 1.5" in diameter in a few spots and are anything but beneficial to performance.
Save until you can afford to do all of these mods at once so you can really feel the difference. Doing it stages might leave you feeling a little flat as far as a "wow" factor is concerned.
Picking up a set of aftermarket headers will really help you out too. The stocker are crushed down to 1.5" in diameter in a few spots and are anything but beneficial to performance.
Save until you can afford to do all of these mods at once so you can really feel the difference. Doing it stages might leave you feeling a little flat as far as a "wow" factor is concerned.
- Mar 30, 2014
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ok thanks,and i totally agree with 75mm pro-m maf along with thestock 65mm tb,55 mm maf is to small
Ok wait....did you change out to a 65mm throttle body at some point, or are you under the impression that the stock one measures 65mm? The stock unit is only 60mm in diameter, in which case a throttle body upgrade might be warranted. In that instance, a 70mm would be what I would recommend
I only stated that you shouldn't upgrade from a 65mm to a 70mm, because the airflow and subsequent horsepower gained between the two would only be something you saw on a dyno sheet. But....if you're upgrading from the stock 60mm unit, go with the 70mm right off the hop. The price difference between a 65mm and a 70mm throttle body is only about $30 and the power difference between a stocker and a 70mm with your above list of supporting mods (as well as the ones I recommended) could be as much as 10-12hp.
BTW...you'll need access to a dremel or a die grinder, as the Cobra intake manifold will need to be opened up a tad to accommodate the 70mm throttle body.
- Mar 30, 2014
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Dude you gotta type more clearly and stop rushing through for good answers. What gears are in the car i didnt see that answered anywhere unless i missed it . I think the car may run better with a little more timing in it too but thats variable on the car and how much it will take until it detonates.
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