ok guys i'll give u all the info up front
LO3...700R4...car weighs 3470lbs...heres the old mod list and times...cat-back,160stat, hyperthech thermomaster chip, ultimate tbi mods,14*3 flat based open element, IAT resistor, torque converter lock-up switch, SLP Torsen Posi w/Richmond 3.73's...best ET 15.841 @ 86.41mph w/a bad 2.363 60'

Heres the new...same mods as above plus i added Headman 1 5/8 primiaries w/3" collecters and a y-pipe...and the new times are...a 16.3 @ 82 mph!!!...what the hell happend??? well here are my ideas

1-damaged O2 sensor will doing exhaust work=improper fuel mixture
2-Smog Pump=new headers have no AIR tubes so the smog pump is just kinda hanging out right now not hooked up just injected air into the engine bay
3-VSS=well the speedo gears aren't totally accurate once it goes into OD...actually off by almost 10mph...could this possibly be sending improper readings to the ECM?
4-PowerBand movement=does the car wanna run out the tach a little more now?...shifts outta 1st and 4,500rpm

the timeslips are almost the same as my olds until i hit the 1/8th mile and 1,000 ft mark...any help would be great

 

forgot to mention the car did go 86mph after the headers (same mph as my previous best) but that was my best of the day w/accompanied my best 60'...a 2.1

 

maybe you need a chip and or more fuel pressre. Might be going lean on top.

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-Tas
'89 Formula WS-6

305, TBI, auto, 14x3 chrome flat based open element with K&N, Milodon 160* thermo, functional Formula hood, cross-flow Flowmaster, '99z28 rear pipes and tips....

To be installed eventually far far far into the future: Yours if the price is right and I don't have to ship :
Hooker 1-5/8" 50 state legal headers, Dynomax 3" I pipe (PN 44063 and 43248), Catco 3" cat, and injector spacer.

Super GRK_Taz World
F-Body Dual Exaust
EFI & Intake Options
AOL IM: superGRtaz

 

Hey. a little off topic here but did that hypertech thermo chip help out much power wise, i.e. was it worth getting? I was thinking about popping one in along with a 180 degree t-stat in the spring along with similar stuff to what you've done.

But on topic, I'd guess it needs a fuel pressure bump too, it may just not be delivering enough fuel up top. Does it feel weaker on the top end, say up above 3500?

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88 Camaro (The mighty LO3 SC!)
305TBI/700R4/2.73/123,XXX miles
14" Open Element and Flowmaster 80 seires

Next up: headers and gears

 

well i found out that the car was leaning out a little but i don't think thats the whole problem...the car just wasn't puttin out enough fuel in the cold dense air...anyone else have any ideas?...as for the chip if u can get it for free like i did sure but don't pay for one...didn't notice anything

 

c'mon guys i need your input...especially from some of the TBI veterans here

 

I would say spend the 100 bucks and get a walbro fuel pump. Then adjust your pressure. It sounds like you are lean and I hear that is common with those mods.


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1990 RS 305 TBI T-5
.5" turbocity spacer
Edelbrock TBI intake
180* stat
Summit 14X3 OpenElement W/k&N
Hooker 3" Areochamber
MSD - Wires, Cap, Rotor, Coil
Bosch Platinum +4 plugs
Metallic Red w/28,000 Pampered miles
(Still have the original wiper blades)

 

Hmmm, well, I'd have to say that if it's not a severe lack of fuel (fix it anyways, make your FPR adjustable, if it is already, take the time to increase it) it might be because you need to rev the car a little more.
Most of the mods you have done (open air element, 1 5/8" headers, cat-back, and ultimate TBI mods) are going to ALLOW you to make more horsepower up top. Not necessarily increase the engines ability to make hp, just make it easier to realize it's full potential. Anyways, you're going to have to get the car into it's power band. Shifting at 4,500 is not going to do it. After similar mods to my car, the shift point could move progressively higher. I've heard that LO3 valve springs can take about 5,300 RPM. Try shifting at that, and get back to us.
Good luck.

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No guts, no glory.

 

I have to say buy a chip, I saw a big difference when I put mine in and its only the street runner. I also manually shift my car at a little above 5 grand, 4500 I think is to low. I can run a 15.1 with mods listed below. As far as fuel pressure, I tried an adjustable unit and with increased presser the car ran worse! So I just put my stock unit back and car runs good. Sorry I'm unable to help more but try manually shifting and see what happens

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Trans Go Kit
Hooker Areochamber 3in Cat-Back (Gutted Cat)
Hypertech Chip (Street Runner)
Cowl Induction Hood
Under Drive Pulleys
Open Element Air Filter
1/2 In TBI Spacer and
TBI Injector Spacer
Best E/T 15.170 @ 89.82

 

thanks guys...as far as shift points i let it shift itself becuase im bracket racing the car and its more consistant...but who wants to go conistantly slow right...im gonna do the adjustable regulator and bump the timing up (its at top dead center) and probably the IAT resistor may hafta go back in...any ideas of a good fuel pressure setting?...they were all "suppossed" to be the same from the factory but we all know it didn't happen that way...keep 'em commin

 

Dude, you need more fuel! The engine will make it's most horsepower when it's running closer to 13:1 a perfect example is Tim and his extreamely rich running piece! His car runs dog rich at idle but doesn't get starved when he gets "up there."
Please believe me, you need more fuel, do NOT bump timing up unless you run with a scan tool to make absolute sure you aren't getting any knock.
Lets just say I burned an eprom which ran too lean and I ran a second slower in the 1/4 AND I had just gotten the 3.73 and posi!!! I didn't have a "rich" chip or I would have taken it down the track with the other eprom. As for shift points, try resetting your TV cable. You need to just pinch in that tab and then open throttle to reset.

------------------
, Jon (350 TBI!)
91 Red My website

 

I have most of the same mods you do and I run alot faster. I run 11 psi of fuel pressure, and shift at 5000. I had a simular problem with the car slowing after th 1/8 mile. The car would fall flat on its face after 3800 and make alot of noise. It turned out the tranny mount was ripped in three places. It would slow me down ALOT. I would vary about 4 tenths slow. Hope this helps!

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1991 Chevy Camaro RS TBI w/auto
Mods:
Edelbrock TES Headers, REALLY high flow cat, 2 1/2 in catback flowmaster, 160 stat, hypertech chip, MSD ignition (rotor, cap, superconduct. wires), Bosch quad4 plugs, Ram Air Box twin snorkel, all TBI mods, no smog stuff, no EGR, lots of suspention and alignment upgrades, and a big Chevy bowtie sticker on the back.

Fastest e.t.:
15.64 @ 87.8mph

 

I forgot...I run 6 deg. advanced, with NOS racing fuel additive

 

ok guys looks like i should get off my a** and do the adjustable regulator mod soon....jon since the knock sensor isn't effective at an idle why can't i set the timing by ear at an idle?....thanks guys

 

because the ecm increases it non-linearly through the rpms, setting advance at idle might be ok, but when your engine goes to give it 24 more deg at wot, good luck keeping the engine from knocking.

also, if i were you, i would buy one of the vacuum adjustable regulators. from the sounds of anyone who has put one in, they have better idle, and dont have a wot lean condition. just make sure to use your stock spring, instead of the one that is in it already or you will be pumpin at 14psi at wot.

yank your emissions, completely, no reason to leave it just hangin in there pumpin into the engine compartment.

put your iat back in, reset your computer, drive for a few days with the iat, when you go to the track, try different resistors on a run, then try your iat in, and see what it runs. i think you will be best with an iat.
edit: that is, if you solve your initial fuel problem first.



[This message has been edited by snflupigus (edited September 18, 2001).]

 

snuffy, where do i obtain a vaccum advance regulator and how much am i going to spend?...also im am yanking the smog pump as soon as it get the new belt...i also may try to do some 02 sensor tunning...thanks

 

hey guys...whats a good reading for WOT from the volt meter (if i do o2 tunning)...if i remember correctly something like .900 is a good mixture?...thanks for your help i gotta get this thing runnin right