88 350 tpi formula

iTrader: (9)

well I have been looking through pages and pages of arap posts and I don't seem to see anyone mention how low the wot timming table is. why is the stock 89 formula bin have soo much more timing?

I have been playing with my timing at wot and it seems like stock is too much for my combo and this low curve works better?

I am running a choppey cam and I thought they liked more timing but, it seems like I need to run 12 deg base and keep the WOT advance very low 1 deg until about 4000-4500 and then add 9 deg. does this even sound right?

RednGold86Z

iTrader: (1)

Are you reading the timing tables correctly?

WOT timing is the PE timing PLUS the spark table timing. So, just add the two numbers together to get the actual timing.

88 350 tpi formula

iTrader: (9)

I need to look at "Main Spark Advance Vs. RPM Vs. Load" and "Spark Advance in WOT Vs RPM" right?

in the stock APYU bin.

Spark Advance Vs. RPM Vs. Load

rpm deg.
400 2.1
1200 3.9
2000 4.9
3200 5.6
4800 8.1

Main Spark Advance Vs. RPM Vs. Load (this is just the high load tables)


RPM Load Value (LV8)
176 192 208
400 20.0 20.0 20.0
600 20.0 20.0 20.0
800 20.7 20.7 20.7
1000 19.0 19.0 19.0
1200 16.2 16.2 16.2
1400 19.0 19.0 19.0
1600 22.1 22.1 22.1
1800 22.1 22.1 22.1
2000 24.3 22.1 22.1
2200 24.3 22.1 22.1
2400 24.3 22.1 22.1
2800 20.0 20.0 20.0
3200 21.1 20.4 20.4
3600 21.8 20.0 20.0
4000 21.8 20.4 20.4
4400 23.9 22.5 22.5
4800 25.0 23.2 23.2


so @ 400 rpm I have base timing set to 12 deg. + the 20.4 + 2.1 = 34.5 total
@ 1200 rpm 12 + 16.2 + 3.9 = 32.1
@ 2000 rpm 12 + 22.1 + 4.9 = 39.0
@ 3200 rpm 12 + 20.4 + 5.6 = 38.
@ 4800 rpm 12 + 23.2 + 8.1 = 43.3


ARAP is........

@ 400 rpm 12 + 20.0 + 0.0 = 32. total
@ 1200 rpm 12 + 20.0 + 1.1 = 33.1
@ 2000 rpm 12 + 26.0 + 1.1 = 39.1
@ 3200 rpm 12 + 22.9 + 9.1 = 44.
@ 4800 rpm 12 + 35.2 + 1.1 = 48.3


they are similar in over all timming but, they act like night and day in the car?

bassically my goal was to start with a base bin that worked well and then adjust and tune for my specific combo. so now I need to know why does it run so much better with arap? the only changes I did was change the inj. size

with the apyu bin in surges and pops in pipes under wot, manually adjusting the timming forward and backward a few-several deg makes no diffeance

with arap it has some crusing issues at times but in wot it has no problems (no knock counts that showed up on the scanner but, I plan to take a snap shot and see what is going on)

junkcltr

iTrader: (1)

Since you didn't list any mods then I am assuming that you are saying you took your stock TPI engine and dropped in larger injectors. Since there is no mention of tuning the injector constants, the engine is running rich. Therefore, you changed the AFR at WOT. Therefore, timing may need to be changed.

Why change the stock distr. base timing on a stock engine? Why not change the timing in the BIN? It sounds like you have the tools to reprogram them.

88 350 tpi formula

iTrader: (9)

anyway I bassiaclly built the motor using parts I had left over (that's why some of the stuff I am about to list seem odd slightly miss matched and over kill


what I have is a 1989 formula 350 car/pcm and harness

roller sbc block .040 over,

afr 195 heads with a 64 cc chambers ,

cam is a hyd. roller .544/.554 lift 230/236 dur. @.050 112 LSA
with 4 deg adv. valve timming is...
Open Int. 7 BTDC .. Open Ex 54 BBDC
Close Int. 43 ABDC .. Close Ex 2 ATDC

holley stealth ram,

52mm bbk throttle body,

ford 42# fuel injectors,

walbro high volume intank pump,

hooker 1 3/4" long tube headers running through a modified slp ls1 longtube y-pipe to a slp catback for thirdgens

t-5 trans,

7.75 rear with 3.70 gears and 26" tall tires


not trying to be smart just trying to list everything. what I ment about changing the injectors is the only change to those two bins. total timming seems high but, I have never built an eng with this much cam.

I am running 87 since I have right around 9.5:1 comp. aluminum heads and the cam.
----------

just that is easy hook up the timing light turn it a few deg. and see if it helps or not. then do it right and burn the bin

RednGold86Z

iTrader: (1)

DON'T ADD THE BASE TIMING!!!!!!!! (To all newbies out there). The base timing is not part of the calculation when looking at the numbers in this way.

89Vert

also make sure your base timing is set to 6* on the engine if its 6* on the chip

88 350 tpi formula

iTrader: (9)

ok guys so if I set the chip to 12 base will it stay at 12 base? or will the computer subtract the extra 6 deg?


with this cam can you guys tell me how I should start with for a timing curve? the best I can find is ...... the old dizzy cars are setup with stops and such in the dizzy with bigger cams but run 12 or more base timing , run a total max timing around 36-38 in the high rpm range and bring the advance in around 2000 rpm


so should I take a stock 350 tpi bin of course set the inj. constant to 42# and set the base timing in the chip to 12 deg?

or set the dizzy back to 6 deg. and then change the tables in the chip to add 6 deg and slowly tapper off the added timming so I don't go over a max of 36 deg total timing?

bassically I want to get the curve setup so it at least runs pretty well with out detonating and breaking a pistion or ring and do the fine tuning from there.

from what I gather I might fingers crossed get a chance to run it on a chassis dyno for the tune but, I need to get the car there which is about 50 miles away

RednGold86Z

iTrader: (1)

Leave your base timing at 12 (a bigger cam engine will start easier with more base timing). Change the base timing in the chip to say 12. Use ARAP timing table ONLY if you have a working knock sensor. That 9 degree bump I think is meant to trip the engine into knock, and ride the sensor all the way up.
Use the table as is. Drive it. Try a few degrees more down low at higher loads, if it's necessary (kind of depends on the torque converter).
Do some driving, check for knock. Get your MAF tables straightened out. Once the MAF tables are smooth, and BLMs 120 to 128, tweak the Acceleration Enrichment (pump shot).
Once that's good, get (buy, beg, borrow, steal) a wideband in there and do the full throttle Power Enrichment. Your engine will probably take it beyond the MAF's ability to read accurately, so this will be important at higher RPMs.