racerx520

iTrader: (1)

so ive been working on my 87 t/a for a while, she's got a 305 TPI but it doenst really move very well. i was talking to someone who used to own a RS camaro with the same motor and he was saying he was able to cut the back tires loose (255's) and even chirp the tires going into second gear with his auto transmission.
should i be getting more power to do this out of my current setup:

motor:
305
shorty headers
cool air intake
throttle body aerofoil

suspension/tires:
yokohoma 255R15 tires
KYB AGX shocks/struts
Wonderbar
Subframe connectors

i feel like with this stuff i should be getting atleast a littlemore power but i seem toget less...iwas trying to think of things that could be wrong, could there possibly be something to do with either somehow my plenum being gunkedup or my injectors being extremely dirty?

Hoffy91

That sounds iffy. Im not a pro TPI guy, but my buddy had a 305 TPI in his 85 Iroc, and yeah he could bust the rear tires loose. Granted he was doing a brake stand. And I dont think the tire chirp sounds right... That guy probably did it ONE time right after it rained and it probably spun a little bit . Your performance parts will help, but its not gonna boost your HP by 40 or something. you can burn rubber all day, but im not sure about chirpin tires in shifting

Rolling Thunder

Well concidering the LB9s only make roughly 200 hp from the factory and with shorty headers and a cold air intake is probably good for about 20-30 hp so it helps and should make a noticable difference but will it make you chirp 255s into second? No. For starters if it was an RS the guy owned, RS camaros didnt come with TPI if im not mistaken not even an option so if he had it it must have been swapped which means other work could have been done (and probably was) as well. Second assumeing he chirped 255s that may not mean a whole lot because theres alot of factors that go into something like that. Quality of the tires, condition of the road, std rear or posi, rear differential ratio, shift kit or a corvette servo perhaps. Also if he was peeling out through first and it shifts into second of course it will chirp alittle just by nature of the fact that the wheels were still spining when it shifted. So its really hard to make a comparison based on that. The question is does the car feel more powerful after the mods? You should be able to break the rear tires loose from a stand still without doing a break stand even with posi if you really mash the pedal. Wont do anything crazy but you should be able to light them up not much beond that though.

racerx520

iTrader: (1)

well thats the thing...i cant just let go of the brake, mash the gas and spin the tires, although i'd really really love to! lol
if i just mash on the gas, it just will seem like its got some force working against it, then as it gets up in rpm's (about 2500-3000)it'll start to finally take off. it does have posi too and the only way i can get the tires to crack loose is if i make a right hand turn, and in the middle of the turn just really stomp on the pedal, that can get me to spin the tires for maybe 2 seconds if im lucky lol then the posi will kick in and then it'll stop, and then it'll seem almost like it kicks down a gear then it'll just go. oh, i forgot to mention, whenever i go onto the road i like to do this with, its uphill lol.

i feel like i should be getting more power out of this motor, and the trans thats in it is replaced but its got 80k miles on it...i dont know what else it could be

Rolling Thunder

Well it sounds like you should give your car a good checking over maby a tune up because my completely stock 86 T/A with the 305 TPI auto posi 2.77 rear and 245s (about as bad as it gets for wanting to do burn outs in concerned) will peel out on a hard launch from a dead stop. Again its not overwhelmingly impressive and you have to be at a dead stop or very close to it or in a turn but it will break loose. Now you say it feels like theres a force working against your car on a launch untill like 3k im alittle confused by what you mean. Like you step on the pedal and it boggs or just dosnt want to go?

racerx520

iTrader: (1)

yes it does kinda bog down...i didnt want to use that exact word cuz the first thing that comes to mind with bogging is transmission problems to me lol

Irocz28NCHS

wow not to steal ur thread man but im having the exact same problem as you. so im going to keep my eye on this thread but i have the same engine and it seems to kinda bogg down too. and i can not seem to break my tires loose either.

Rolling Thunder

Well its ok no worries bogging is usually engine related. First off do you have a check engine light or any trouble codes stored in the comp? When was the last time you did a good tune up?

racerx520

iTrader: (1)

no, no check engine light, and tune up was done 2 years ago this fall....sad story really....car was 20 yrs old and the 2 owners before me NEVER changed the wires, cap, or rotor...after changing that (because it began to miss bigtime when i floored it) then it all changed, i felt like i was driving a lambo or something. then i added the headers, new plugs and did a few other mods to it and still nothing.

i replaced the MAF sensor about 4 years ago with a rebuilt. i have used this 'dump in your fuel tank and it'll fix your motor' injector cleaners and to no avail i havent seen any long term improvement that by cleaning dirty injectors would give. i am unsure if these injectors are dirty, they are most likely original (everything inthis car is from 1987 pretty much lol)

i also change my oil ever 2500-3000 miles, not that this should pose too much of a problem. i replaced the valve seals but yet they still seem to leak when its very warm out and i am in need of an oil change it would seem but i dont think this would have anything really to do with losing power.

i am just trying to think outloud about anything and everything that could be involved.

Rolling Thunder

Ok yea i know how that goes i just picked up a nice lower miles 86 trans am that was about to be parted and scrapped because the guy just kinda abandoned it at his mechanics garage. It was owned by a truck driver so he was never around to drive it. So yea theres alot of stuff thats original on that car most of it still works well though except the tires lol. Anyways the first thing ide do is check the timing, check the fuel pressure, and just jump the diagnostic terminal because even though you dont have a check engin light there could still be codes stored.

racerx520

iTrader: (1)

well its got a brand new fuel pump in it...had to fix a crack in the gas tank neck so we figured it would be out, might as well replace the pump lol...the filter is new as well and how exactly do i check the idle? i was thinking next tune up of getting th e MSD cap and rotor that they sell and the coil too, is that any good? would that possibly help if im not getting enough spark?

Rolling Thunder

Well for starters the msd stuff although good quality isnt really neccessary on a stock motor. Alot of people look for the highest voltage rated coil they can find but it reality the coil will only generate enough voltage to create a spark. For higer compressions and exotic race fuels you need more voltage to cause a spark but again for a near stock car a regular oem piece is fine and you wont really notice any difference unless of course your current cap rotor or coil is no good. A good set of aftermarket plug wires on the other hand is alittle different though. The factory ones are fine and wont cause any problems and its nothing youll notice performance wise but does help a little. Now even though it has a new pump in it there could always be crap in the tank that plugged up the sock it could have a bad fuel pressure regulator plugged return line ect. So ide still check the pressure just to be 100% sure its fine. Takeing a glance at the factory manual it has a pretty well defined list of things that can cause a bogg or hesitation as you describe and probaby wouldnt throw a trouble code (though ide check anyways for stored codes). Heres how it breaks down.

Step one
the visual check

Check for stored trouble codes

Look for vaccum leaks in the vacuum lines/ manifold / throttle body mount ( can be done by visually looking for cracks and splits in the lines and spraying alittle propane over the lines and manifold and if you notice a change in idle its because the motor has a leak there and sucked in propane instead of just air)

look for air leaks between the maf sensor and the throttle body causeing air to enter the system without being measured

look for cracked plug wires and look over the cap and rotor for wear and carbon tracking

General inspection of wiring for broken wires pinched wires melted wired ect

if the visual inspection checks out its time to look alittle deeper but thats a good starting point. also a question for u when u ask "how exactly do i check the idle?" what about the idle exactly do you want to check?

BlueIroc-Z

iTrader: (6)

I too have been unable to break the tires loose with my 305 TPI... I know that is not really a very exact measurement of power, but hey if everyone else's 305 TPI can do it to some degree and mine can't, then there must be some issue right?

Anyway, I did a datalog on mine and noticed a significant (constantly pegged 160 BLMs) lean condition throughout all driving and idle conditions. I figured that was the source of my powerloss, but have yet to fix it. As near as I can tell it is due to the fact that the previous owners didn't switch PROM chips when they swapped out the original 350 for the 305. Don't ask me why they would do that swap, I would have wanted to ask them the same question had I known it was a 305 when I was buying the car.

Anyway, if you get through all the basic checks, you may want to consider getting set up to do a datalog and see if the computer can point you in the right direction.

FireDemonSiC

Just something to think about.

If one of the uneducated previous owners put in a torque converter with too high a stall, it would cause what you are describing. Probably not the case, but worth checking out.

racerx520

iTrader: (1)

torque converter is brand new as of last year, there shouldnt be anything in the fuel tank because when i replaced the fuel pump i had to drain the tank and have a crack re soldered in it, but this has been an issue since ive owned the car.

i will check the MAF mainly cuz the cool air intake is a home made thing and could possibly be leaking, the wires i inspect quite regularly because they always somehow hit my headers even if i zip tie them in like 18 different places somehow they'll hit.

over the past couple days my car has been feeling frisky and has actually broken the tires loose a couple times from a dead stop just going straight, this will probably change now that ive mentioned it lol.

here is one other thing which crossed my mind which i am unsure of if it'll make a huge difference...my oil, now my motor has 165k miles on it and is a bit worn at that age, my father (a GM mechanic) recomended that i put 10w30 in it instead of 5w30 because it is more viscous and would less likely run through the motor...but i was thinking could this somehow impede the motor from functioning properly? i just changed the oil with 10w30 but next time i will try the 5w

and blue iroc...i have heard of some people doing a transition of taking a 350 motor and putting 305 heads on it to increase the compression to give it a bit more power, this could be the case but if it is, then it needs to use a higher octane fuel from what i understand...not too positive but something to look into if at all possible

Rolling Thunder

Well 2 things first im not so much sayin that your problem is crap in the tank plugging the sock i more trying to say that even though the pumps new theres a multitude of things that can cause the fuel pressure to be incorrect so it really needs to be checked. One of the primary causes of a hesitation or a bog is a lean mixture on a launch when it should be alittle on the rich side. When you look over the factory manual a vast majority of the things to inspect are all pertaining to things that could make the car run lean like a vacuume leak. Fuel pressure if to low can also cause a lean condition and thats why it really should be checked even with a new pump installed just to be 100% sure. Lastly about the oil personally ide run 10-w30 that was the original recomended weight for our cars. the 5w-30 although is now listed as a recomended weight of oil along with the 10w-30 is more for slightly better fuel economy but also will slightly reduce the oil pressure and could potentially like your father said be burned off at a slightly faster rate due to its lighter weight. At the end of the day eather should be fine and different climates may push my personal preferance one way or the other but my oppinion is just stick with the 10w-30 unless you live in like alaska lol.

edit: the other thing i meant to mention about although probably unrelated to this problem be careful about now you route your wires as they can induce a spark into adjacent wires if not routed properly. This can cause the car to just run kinda rough and lose alittle power.

Rolling Thunder

My guess is if you cant break lose chances are you have an issue. Furthermore i think you may have already found the problem. As stated in an earlier post orne common cause of hesitation or a bog is a lean condition when you launch the car and really should be a bit on the rich side. Now if the car is not set up right like you said if its a 305 with a 350 prom or whaterever then of course as im sure you know it will never run right so theres really not much point in trying to do any troubleshooting untill thats corrected.

BlueIroc-Z

iTrader: (6)

I know, I just haven't "fixed" it yet because I got side tracked with T-top seals and I have been trying to find a place that can burn me a chip for cheap, seeing as how I just need a stock .bin and no actual tuning. I was gonna do that myself, but the programmer I bought was DOA. Other than the chip issue and the symptoms it causes my car runs pretty much perfect.
When my machinist told me that when I took the heads in for a valve job, I was hoping that I would go back home to find a 350 block... But, nope, casting # was clearly a "5.0L" and bore measurement confirmed it was indeed a 305. Man, I was pissed. Never again will I just look at the VIN and call it good.

I'm sorry if my issue seems to have hijacked your thread. I originally just wanted to make the suggestion that if every thing checks out good, you might look into computer diagnostics as a next step.

racerx520

iTrader: (1)

dont worry about it...so far it seems to still be alive...

and ok, so we've established one area to check is the fuel pressure which can be controlled by the pump, filter, injectors (right??) and the vacuum pressure...now i know how i can check the vacuum, but not so much on the actual fuel pressure other than if i had a scan tool, which i learned in my auto shop class when i took one, but i do not own one. where can i go from there? i know you said i can look stuff up in the owners manual but i have a feeling thats going to have some sort of measurement.

oh and one last thing, the oil cap on my valve cover says use 5w30 oil on it instead of 10w30, but like you said, shouldnt pose any sort of problem

Rolling Thunder

Well theres alot of things that can effect fuel pressure. Fortunetly we dont have to car about them unless we detect a problem lol. To measure the fuel pressure the only way you can really do it with a fuel pressure guage which GM was kind enough to include a fitting for this built into in their design. I beilieve with the vaccum line to the regulator dissconnected the fuel pressure should be 43 psi about?

burnout88

When I first bought my 88 305 TPI it would not turn the tires over and ran a 16.3 in the quarter, it was a 305 auto tpi with a 2.77 gear. I added a 3.73 gear, headers, MSD wires and tuneup, ported the plenuem, a chip, 52 mm throttle body and now the best it will run on motor is a 14.9.

Change the gear, I got .6 tenths in the quarter with the gear and it totally changed the launch on the car.

BlueIroc-Z

iTrader: (6)

True, changing the rear end ratio will definitely improve the launch. But, I think what we are doing here is using the ability (or inability in this case) to break the tires loose as a way to judge the running condition of the motor. Because it seems to be the general consensus that a stock 305 TPI should be able to break the tires loose to some extent (in a straight line, w/ no brakes) no matter what gears are in it, I would say that there is some other issue causing the motor to make less power than it should.

Although being able to do a burnout is probably a terribly basic way to judge engine performance, I wouldn't say it's completely invalid...

c4ta

i was just going to start a topic like this one. i bought my 88'TA 3 months ago. i would spin them like crazy. not so much anymore. 112k on it now. 109 when i bought it. high flow cat. 3" cat back flowmaster 88. underdrive power/amp kit. and air foil. k&n filter also. cap/rotor/wires look fairly new but i am going to start there. fuel pump is pretty loud also and make some weird sounds. so new pump and filter. but its just strange that 3 months ago it didn't what i was on it would spin them. you would think 5-10hp that i have added should not hold it back any. should still do the same. but i will keep reading.

flaming-ford

iTrader: (7)

check your fp at the rail as said above. also aftermarket rebuilt maf sensors surely don't seem to run to well on these motors from what i've heard. a delco maf or a replaced maf with a different style off a newer vehicle or such may be the way to go.

btw i have a 305 tpi and unless i drop the clutch at higher than 1800 rpms or peg it in a turn or just get lucky it won't spin from a dead stop.... i have a t5 5 speed 3.08 gear ratio, posi, all bolt on's other than a msd box i have sitting in the garage. before under drives, new tuneup, 1.6 roller rockers, adjusting fp and timing and adding new 255/50s to the rear it ran a 15.1.... now it would run a mid to low 14 easily and it still won't realy spin the tires unless you try.

as for my last 305 tbi car it had a full msd ignition 1.6 roller rockers and an open element and it would never even if i was lucky brake the tires lose without holding my brakes or being in a bad traction spot....

i think you guys are crazy if you can smoke 255/50s these suspensions in working order work very well at even hooking 300whp on the street with a decent sized tire. If you are smoking your tires just by pegging it from a dead stop then your suspension is either worn out, you have crappy tires or a big *** converter.......... just my opinion. that is taking in to consideration most if not all of the cars who priorly post have a rearend ratio as high as mine or even worse.

c4ta

i have bald 245/50's on mine.

Chevy8588

iTrader: (1)

i had stock tired on my old 88 and all brand new suspension in the read with a 2.77 posi and a 305 TBI and i could break loose from a dead stop with out standing on the brakes easilly, no wheel hop either, donuts were fun.

BigWhiteGTP

Summer time temps have alot to do with lack of wheel spin-ability. Think about it. The melting tarred asphault can get upwards of 150* and the car is breathing all that in. Now the tires get a little grippier because of the heat.

The exact opposite in the winter. The asphault is much much cooler, as are the temps. And again, the car is sucking in air that is 1/3 the temp of summer if not more. And the tires aren't melting either in fact, they are harder so it will be even easier to spin

SupplySgt

I noticed someone talking about hp. hp is not what makes you shoot off the line or burn rubber, that's torque. and the 305 TPI is rated at 295ft-lbs of torque. more than enough to burn some nice rubber. I have an 87 IROC (granted it is a manual) but I have no problem burning rubber (not a good idea till i get better tires though). and I can burn them just fine when it's 95 degrees out. 305 shouldn't have any issues doing it during the summer. sounds like something in the fuel mixture to me. too lean. Good luck though it's no fun not being able to do burnouts.