1991sleeper

iTrader: (-3)

Help ! What do I do when I get VE overflow ? I just increased the FP by like 3psi and left the BPC alone ... This crap is getting old doin as I start gettin VE close I run into overflow and gotta start all over WTF !

1991sleeper

iTrader: (-3)

Pulled up at a red light today right never to a late 80's Z28 Camaro ... He revved up and asked what u got in that thing I smiled n said oh just a little 305 .. u? ... Oh mine has the 350 wanna run? So I say sure why not ... And sucked his doors off before he went under the light hahaha ...... Just a base model firebird with a 305 TBI .... Still have some major tuning to do ... Every time I get the VE close I gotta start over cause I run into VE overflow .... FP is at 26psi now at WOT and around 18 at idle

ownor

iTrader: (5)

resized rods on arp bolts, main studs and main bores align honed with good tolerances and a good balancing job like it seems you got should be running 6.5 no problem imho. if you really need the rev range or you're running into flow limitations already, well that's another question. also maybe valvetrain issues, not sure.

haven't had it happen that bad but i just hate this reservoir full of corrosive brake fluid with the kinda leaky top cover on these cars..

damn yeah open headers be sound'n good all in all, good build you got goin on there to me, i'm subscribing

1991sleeper

iTrader: (-3)

Haha thanks man ... It sounds pretty good for a little 305 especially after about 4500 ... And as far as I know there are no flow limitations or valve train issues .. The only possible limitations I can think of are the throttle body (CFM tech 620cfm unit ) and possibly my dinky little headers .... But I have a vacuum gauge in the car so if I ever get it tuned where I feel safe running it up to 6000rpm I'll know if it has an intake restriction seeing as I'm at sea level map should read 100 at WOT ... Sometimes with the key on engine off I see 101-102 map

ownor

iTrader: (5)

I was gonna say exactly that, you can always check with either a vac gauge or just the EBL WUD or logs to see if you get up to atmospheric MAP. btw interesting detail about being at sea level, i was always wondering what that would like in terms of MAP. does it ever go below 100 MAP with engine off (baro)?
anyways yeah think it's better to have it all dialed in first, you dont want any high rpm hiccups i guess but yeah should be within a few kPa of atmospheric MAP unless the intake is restrictive, can check that. think it sounds like a strong 305 build plan otherwise, curious to what numbers you'll be cranking out

1991sleeper

iTrader: (-3)

Yea it feels pretty strong so far but I believe there's a lot left in it ... I really haven't messed with SA a lot yet either cause I can't get VE right ... But I'm gonna try the correction offsets from the 3001 bin along with the SA tables I been running the 3006 SA tables ... And yes actually I do see baro at 98-99 sometimes too .. I guess it just depends on the weather ... And I'm actuall a little above sea level in the far northwest corner of alabama about 30 min from tenesse and 10 min from Mississippi but I live in a valley right next to the Tennessee river so not far from sea level mabey couple 100 feet at most ..... And I'm right there with ya I can't wait to get it tuned right to see how it's gonna run the track should b open late February , I'm hoping to run 8.000 in 1/8th mile .... With the basically stock Lo3 shifting at 4500 I ran 9.802 at around 71-72 mph .... All it had was 1.6roller rockers ,TBI spacer , bigger TB ,CAI headers , full exhaust , 4:10 gears.... And lots of suspension mods with crappy street tires and 2.06 - 2.1 60ft times .... My dads 08 mustang gt CS ran a best of 8.97 that same night with CAI full Exhaust and a tune ... I'm hoping to dust his *** now !! If not ...
100 shot :-)

1991sleeper

iTrader: (-3)

My ole time slips from stock engine beefy suspension and street tires .... I've also added SFC's and took about 150+ lbs off the front end since then plus the engine rebuild shouldake up for some decent times .... Mabey ... I need bigger tires too

ownor

iTrader: (5)

i've never gotten around to drag racing myself, although i been planning to go for ever and longer. i can make sense of quarter times but not sure about eighth mile numbers.. no idea where to put them, if that's slow or fast numbers lol. >2.0 60ft times is not too good tho, since you had a posi with the 4.10 and some susp mods. i would have thought it would hook much better than that. there might be a lot in the tires tho. or in your launch technique, but as said since i never did drag racing i'm not gonna act like i know a whole lot here heh.

1991sleeper

iTrader: (-3)

Yea 60ft sucked it was spinning bad .. And due to tires .. It had some cheapo half dry rotted 50$ used tires with some name I never even heard of and they only had about a 8"wide tread if that

1991sleeper

iTrader: (-3)

This is how good my CAI works .... Look close and u can see the condensation forming on the outside of my throttle body after about 10 min of idleing .... Keep in mind it's about 60 degrees here today but it's got a lot to do with the phenolic TBI adapter too TB stays cold even if I unhook the CAI but it don't form condensation like that with the element in the engine bay ....and there is no exhaust or coolant crossover under the intake and drivability around town is actually quite good

1991sleeper

iTrader: (-3)

One more video for y'all .. The tune is getting much closer I believe but it's down to 40 degrees so soon as it gets a little warmer I'll get y'all a driving video :-o ....

1991sleeper

iTrader: (-3)

Couple pics a the ole fire chicken

ownor

iTrader: (5)

hehe, 40 for me is a pretty nice weather for christmas time, although i guess it rarely gets down that much over(/down) there in bama?
we've been pretty lucky with around 50 deg F the recent days, managed to pull some tuning sessions on a 355 in a friends 88 camaro between getting the belly stuffed and the other usual christmas stuff
hoping the thing you worked out with the FPR clears up some fueling issues?

edit: not bad, i like the looks.. nice rims there (what are they?) and the rear looks much better with the D80 spoiler and the early style rear bumper.. that's what i run on my 89 formula as well
i would loose the 90-up headlight frames tho ^^ and maybe get it lowered just a bit.

1991sleeper

iTrader: (-3)

The rims are gunmetal C6 replicas from OEwheels.com I got em on sale last year for 358$ a set plus 80$ shipping ! So delivered to my door for around 450$ a set

And I would lower it about a inch but the roads here suck n I already scrape my exhaust and air dam area a lot .. And my suspension is already tuned for the current height .. I think I'll just go with a taller tire soon to fill the wheel wells a little more ... The front end actually raised about a half inch from the motor swap n all the weight I removed from the front of the car .. I had to adjust my strut mounts all the way in towards the engine cause the tires were wearing on the outside after I rebuilt the motor and had bad bump steer cause I didn't have a good footprint on the front anymore .., it's much better now but I still need to go in with the mounts some more to get it right so I guess some founders mounts will b next on the list

1991sleeper

iTrader: (-3)

Have a slight problem here ... Did some logging yesterday .. So in this shot I'm cruising at about 50 mph (14.3 AFR 19.9psi FP) I drop to 4th gear (3200rpm) and give it about 80% throttle AFR goes lean for a split second 15:1 AE PW @ 3.998 and DC goes to 103% at 26.5 psi FP ! Wtf ? This is all in the top 3 lines



I'm starting to think I shoulda went with some bigger injectors

ownor

iTrader: (5)

k, nice on those repro wheels then. suspension also makes sense with those roads if you drive it a lot then. the thirdgen is usually only a summer toy for me here so that's different, and roads are prolly better too.

for the log, i see diddly squat without squinting my eyes, so you better learn how to upload files you figured out how to do it for pics, so not sure where the problem is.
that 26.5 psi is at max MAP (=static FP setting)? it seems you need more AE fuel, but yeah with 103% DC you're not going anywhere with commanding more fuel anyways.. what are your min and max VE from the learns so far?

1991sleeper

iTrader: (-3)

Right now my lowest VE is 10 and my highest @ 6000rpm is 90 but idk how close that area is yet I think it may be a little rich

Also note that during this 103% DC event the AFR is way rich like 11:8:1 ... And that 26.5psi is not max ... It goes up to around 29 when under 100% throttle

Street Lethal

iTrader: (16)

Might have missed it, but why is the voltage reading so low in the video...?

1991sleeper

iTrader: (-3)

Under drive pulleys ... After about 1000rpm it goes up to normal

I need to get a higher output alternator

ownor

iTrader: (5)

even a higher output alternator may not have the desired (required) power output at that speed..

1991sleeper

iTrader: (-3)

Well it's worth a shot ... That alternator has been on the car since I've had it 6-7years ... So if that don't remedy the problem I'll put the smaller pulley back on the alternator

ownor

iTrader: (5)

6-7 years+ is a good time for an alternator on these cars, yes, but i'm pretty sure if the alternator was goin south there would be low output at other operating points (other engine speeds) too. and unless you have a 900+ idle and a redline of 6.5k+ i wouldn't go to an underdrive for the alternator, my 2c.

1991sleeper

iTrader: (-3)

Idle is at about 700 - 750 and redline around 6k the new pulley just looks so much better tho :-p ... I may put the old pulley back on just the alternator idk yet ... It's not causing any problems really as long as u don't just crank it let it idle for a long time then just cut it off it still cranks fine ...

ownor

iTrader: (5)

yeah, well as said i'm not a big fan of underdrives, especially the alternator. when racing from a light, the power you gain during the run is probably lost by the additional power needed to charge the battery that you just drained at idle lol.. as said unless you have a high idle on a big cam (say 900 up) and a high redline, there's no need (no gain) to shift the speed range of the accessories up in rpm (UDPs effectively change the "gear ratio" of the belt drive).
i personally just dislike the voltage dip you would typically see when sitting at a light at idle speeds.. even more so when it's dark and there's higher electric power demand.
but since you already have them, oh well.. but can always go back to the old alt pulley and paint it black!

1991sleeper

iTrader: (-3)

Duly noted .... I'll see how I goes and make the correct decision ... The crank pulley is already under driven also so it just a tad bit overkill with ALL the pulleys under drive ... Cooling system still works great but I think the old alternator pulley will fix the problem .....

So anyways .... What do y'all think this motor is capable of ? Like seriously ..... Y'all know all the specs ... With the basically stock LO3 I ran 9.80 in 1/8th @72mph ... With street tires and crappy 60ft .... It's a base model firebird so it not quite as heavy as some other models and I believe I've lost around 200lbs from firewall forward from stock ... Has 4:10 rear end and all tubular suspension in the rear with T-5 trans .... Intake manifold has been ported and matched to heads 620cfm throttle body ... Y'all know the rest .... According to the fuel requirements so far it's capable or around 350 hp and Desktop dyno says closer to 380 with torque around 350 and I'll b shifting @ 6000rpm ... I'm also gonna b going with bigger tires soon about 2" taller to get some gear out of it ...

1991sleeper

iTrader: (-3)

Well I got a datalog and a bin posted up on the tuning with Ebl thread so if anyone can help that would b great

1991sleeper

iTrader: (-3)

Someone helllllpppppp with this stupid tune ! The driveability is good it just don't have the power it should !!! I'm about ready to slap a quadrajunk on there and go

thomas1976

Now that you figured out how to connect the fuel lines and regulator to the TBI, start all over with a fresh LO3 bin.

Fuel pressure For the basic steps to setting up a bin with new fuel pressure do everything RBob has suggested https://www.thirdgen.org/forums/diy-...o3-lt1cam.html

Injectors Here is how to set up the bin when changing injectors https://www.thirdgen.org/forums/post...012-post4.html except you need to use the 55 number from the 55#/hr injectors.

Alu head LT1 SA table https://www.thirdgen.org/forums/post...53-post14.html

SA The recommended total 34-36° SA given by the manufacturer, is at WOT, the heads on my engine are probably almost identical to yours, I used the SA table for LT1 aluminum heads, as starting point.
You will need a little less SA in the low rpm/MAP tables, and I really doubt it will be because of knock, but rater the engine running a little "energetically shaking rough".
For WOT SA use the engine simulator, it will show you a FWHP line with SA line, use that FWHP line for reference and calculate the fuel required for each 90-100kpa (WOT) cell. The SA is easy, use the simulator numbers minus the PE added SA.

VE VE learns, takes a steady and linear throttle, every time you have a nervous foot you waste your time.
After 3-4 30 minutes VE learns, when it starts to stay within +-5, it is time to take a brake and enjoy the car for a while and then go over it with a WB02 if you have one.

Hope this helps

1991sleeper

iTrader: (-3)

Thanks a lot man ! That's more help than I've got regarding tuning so far ! And just for reference I'm using 68# injectors not 55 ... And another thing about SA is my base timing is not perfectly matched to the initial setting yet but I believe it's within 2 degrees ... I need to order a piston stop and see exactly where 0 is on the balancer because of the difference in timing marks from a 305 to a 350 (stupid) .... The driveability is great idle is smooth and steady just when I get on it hard it's running way rich most of the time and power is not what it should b but it may just b deceiving cause of the low end torque loss over stock ... And I haven't really wound it up yet .. I guess I just need to stick it hard and run the **** out of it and see what it will do in the upper rpm's (while data logging of course) oh and I have the initial timing switched to where I use the idle state SA where it stays constant at 21 degrees ... Idk where it should b for these heads but that's about 2 degrees over what I had it with the stock engine .. But anyways I guess I'll just keep working at the tune .. I did put it in close loop for the first time yesterday and int/BLM's were all over the place :-/ ... And driveability went down slightly but not anything too bad just noticed some differences ... If anyone needs me to post a different datalog or something to help u help me let me know .... I think I'm gonna go out and get a short datalog of me driving it a little on the hard side so there's not a bunch of idleing and slow cruising crap y'all gotta look through to find the WOT areas

thomas1976

I know you have 68# injectors, do the equation and you will figure out what I wrote.

I never noticed a difference between O.E. 305 and 350 timing marks, and even if there are 2° inaccuracy I would not worry about it.

Take a new LO3 bin, do the math described in the post above only, load it in the EBL, do VE learns and work with that one.

If you get stuck with the math, let me know

ownor

iTrader: (5)

good input here from thomas i'm not sure i got the above quoted part tho, care to expand on that a bit? otherwise some generic tuning stuff there but nonetheless seemed to be very helpful. you just need to search around this site and read a lot ^^ starting over with a stock bin and just modifying it for the basics might be a good idea though.
after fixing your VE you should probably look at getting AE and PE in line, imho.

thomas1976

Thanks Ownor, for reading and quoting the BS, sorry but I was watching a movie while writing the reply. I just edited it again, should be good now.

Absolutely, basic tuning.

ownor

iTrader: (5)

hehe thomas, ok i see what you did there but still in the dark on what simulator you use to get out the SA

is that a common practice with our engines? so far i've tried to get it right by starting with very generic SA tables, depending on primitive engine characteristics (head material, port/chamber size and design, cam), and then go from there using knock sensor as a feedback. however, a dyno tuning session would be much better here for sure, in order to tune SA for maximum brake torque at every breakpoint in the map..

p.s. btw some engine simulators (dyno2003) indeed produce both FWHP and a VE line

thomas1976

Lets not make confusion here, we are talking about a base calibration for a specific custom engine, the LT1 aluminum head SA table with the engine simulator WOT SA is certainly a good start.

I am aware of the simulated VE line, though not sure how you would make a relation with the required fuel for a cell.

thomas1976

I mainly used desktop dyno 5.

Hope 1991sleeper is gonna come back with questions too

1991sleeper

iTrader: (-3)

Well I copied over the LT1 aluminum head SA table n the motor seems to line it quite well only got a couple knock counts in the lower 1400rpm low load areas so I reduced that area by 1* and increased the WOT areas by 1.5* ... I also reduced the AE rpm multiier table ( inserted negative value ) from 3600rpm up ... And reduced TPSAE by 5% haven't drove it yet (stupid rain) since the AE adjustments but I'll let y'all know where it's at soon As I do

1991sleeper

iTrader: (-3)

And I'm goin back to wrk tomorrow ! Been laid off for 3 months :-/ ,... So I think a wet kit is on the way as well as a billet MSD dizzy !!! Mabey even some long tubes and new exhaust system ... I don't think it likes these little 1.5" primaries (summit brand shorties) but lookiing at it I don't see how the primaries could be any bigger and still b able to get the header flange bolts in !! There tight right now can't even get a socket on em gotta use a open end wrench ... But with the "stock" LO3 these cheapo headers served their purpose and did knock off my 1/8 mile times over the stock manifolds ... But I think they are a restriction @ anything over 4500-5k rpm . After it gets dialed in (tune) I'm planning on shifting at 6k :-o I haven't really had it over 5k yet which is where it should b coming alive

thomas1976

Do not get too carried away with the SA table, leave it as you have it now, you need to do VE learns first (with the new SA table).
Rain is good so you have time to start working on the WOT cells of the VE table, write down the all rpms of each VE cell and calculate required fuel for the given FWHP.

ownor

iTrader: (5)

i agree with keeping the SA a bit low until you're done figuring out VE for the steady-state cruising and then even more critical the AE/PE transitional fueling as said. for a given operating point (load, rpm), a mixture that is off will influence the reaction in the chamber hence your SA tuning will be off as well. best to do it after fueling is consistent, unless the tables you start off with are completely wrong from what you report, i would leave as is right now and tune it later down the road.

1991sleeper

iTrader: (-3)

Well this is what I get from desktop dyno 2000 and that's with EVERYTHING EXACTLY how the motor is actually built like down to the last little detail

1991sleeper

iTrader: (-3)

In just slightly confused on what exactly u wanted me to do with the desktop dyno info like VE line etc

ownor

iTrader: (5)

+1, i'm also not exactly sure all i would do is check if the FWHP is in line with what you based your BPC/fueling on, and maybe the characteristic of the obtained VE curve at WOT is similar than what you tune has in it.. if it shows SA, great but i haven't seen that so far.

1991sleeper

iTrader: (-3)

Do these power numbers seem high to y'all ?

Edit : torque numbers just seem s little high to me but idl .. Guess I'll find out after getting it tuned and run down the track

ownor

iTrader: (5)

did you run it with head flow numbers, exact data from cam card and stuff like that? also i guess desktop dyno will always be on the high side.. and also most don't run a dual exhaust on our cars so i'm not sure how accurate the exhaust modelling fits. torque at 400 lbft is a bit high indeed, but then again that's at 4000 rpm..

also i *think* i remember reading TBI's are flowed differently (the @ .." of water or whatever that figure is) than carbs are, so use e.g. the 620cfm flow numbers with caution. might want to do a little research on which intake option in the simulation model resembles a TBI intake the most.

thomas1976

Need more imput about the cam and head gasket.

1991sleeper

iTrader: (-3)

Yes I input exact head flow numbers , exact cam specs dual plane intake manifold , exact head gasket and quench figures I used the small tube headers and full exhaust option with .030 overbore, .028 think head gasket with pistons .012 in hole and 4.030 bore gasket

1991sleeper

iTrader: (-3)

To simulate the 1.6 ratio roller rockers I input the cam specs at .050 and made sure all the valve events matched on DD2000 then just increased the lift accordingly .... Another thing is the intake manifold is a dual plane with the center divider cut down 1" * 1.75" across so it acts kinda like a single plane and it J's been ported throughout and port matched

ownor

iTrader: (5)

nice quench there. i think you got it all good then. this will be getting very interesting when you put down numbers! if you put in the dual plane manifold in DD then maybe tq may be a little different but nothing too wild off.

1991sleeper

iTrader: (-3)

I'm ising a dual plane carb manifold with TBI adapter

Edit: and yea GM used .040 quench on their motors so that's good enough for me .. Plus with the pistons I'm uning I prolly have about 3 times the quench area that the factory pistons had ( no 45* chamfer all way around piston & no dish !)

ownor

iTrader: (5)

i'm not too sure bout that quench figure on stock motors, i more had like a stock 0.028" HG and the 0.025" down-the-hole figure in my head, which adds up to more like 50 quench depending on tolerances. i never heard about the term quench area tho. you said you're using flattops, that would give the piston head a smaller surface area than the dished pistons. so not sure what this term is describing
i think i remember reading you can't run much more tighter than 0.038 quench on these engines unless you do excessive blueprinting and stuff like that. i think 0.040 is quite a good figure. did you establish the piston deck clearance in all cylinders? just curious, i've yet to do a full build myself (still planning and learning ).