guyp

I am going to the dyno on the 19th and would like to know if someone has any Idea what I can run for timing and what A/F to shoot for? I have been building and dialing in the car for a while and I'm ready for WOT tuning. I have had tons of input from this forum and montecarloss.com.

Specs. 1984 Monte carlo SS, 1988 TPI 350 and 700r4 from a GTA, stock mildly ported heads and intake Plenum, .505/.510 113lsa cam, MSD 6al Ign., Procharger P1SC, 3 row intercooler, Accel DFI Gen6 ecu, GN 8.5 w/3.73.

I seem to be making 10psi @ about 4800. How much total timing should I start with? is 28* to much? I'm thinking A/F should be at 11-11.5 at WOT. I'm at 14-15.5 cruising now and 10.0-10.2 at WOT.

Thanks in advance for any help, I appreciate it.

Guy P

Tony89GTA

iTrader: (7)

I would start with 28* non boosted and 18* at max boost and work up from there with the stock heads, could even go little leaner on your afr.

ZZ3Astro

Those numbers sound pretty good. Total timing might be a bit on the high side though if you're running anything near stock compression. My stock TPI is very sensitive in the 3000-3500 rpm range and will not tolerate much over 14 degrees in the 10 psi range. At 5500 I can run around 18-20 at 12.5 psi, not sure what I've got at 10 psi but probably 20-22 degrees.

I'm assuming you've lowered the compression a bit and as you're running a bit less boost you can get into the mid 20's total timing.

Tony89GTA

iTrader: (7)

He wont be making much boost in the 3000-3500 range with the procharger, though 10 psi at that range must be lot of fun

guyp

Does anyone know what full timing is stock? Reason I ask is Procharger states in thier manual I can run full timing on this setup to 9psi. I am currently at 34* from 3,200 to 5,500 no boost and I am at 26*-28* at about 5,000 and 10psi. I've been running it this way for a few weeks and it seems fine, I called procharger today and the guy told me to start at 28* with a load on the dyno and listen for detonation.

gta324

Look at your memcal (prom) there would be 4 letters, post them and I'll check your timing. I would guess around 32........

83 Crossfire TA

iTrader: (2)

32 might be full timing in the table, but by the time you add in the various adjustments it's not uncommon to see numbers like 47* cruising around...

gta324

Since he was ref to a dyno I assumed it was WOT timing he wanted to know, since under cruise there is no boost.

Cruise is around 40 to 48 degreees, old carbs have up to 52degreees.............

guyp

AKXZ

Will the DFI pull timing if it senses knock? I added 4* to the 8-10psi range a couple weeks ago and its pulling harder. It used to lay over at about 4700-4800 and now pulls good to 5500.

86Z

iTrader: (4)

if your using a knock sensor you monitor for knock under boost on the dyno, i'm running upwards of 30 degrees under boost 14psi max, 3 core intercooler and methanol injection, IAC is cold as can be

on the dyno you can add 2 degree increments under boost and see what you get, i hit a point when i added 2 that i lost power.

gta324

didnt have exactly that file but looking at some others from 88-89

F-body has around 31deg at 4800rpm WOT

Y-body has around 36deg at 4800rpm WOT (al-heads) even found one for a stick that had 40degrees at wot!......

guyp

Thanks guys, hopefully its good air on dyno day.

guyp

Not the best day for dynoing(88 degrees) but it made 336.3HP@4,700rpm and 376.0TQ at 4,600rpm @9psi. Power drops off fast after 4,700 even with boost climbing to 12psi at 5,300(280hp). Now I'll have to recaliberate the trans. governor shift points and see what it will run.

ZZ3Astro

What are the duration specs on your cam at .050? Your torque is exactly what mine was (before I intercooled it), except yours is 1000 rpm later. And of course your peak hp is quite a bit higher than mine was, and about 500 rpm higher than my peak as well. I also just realized I never dynoed mine with the intercooler on it! I was able to add about 5 ot 6 degrees of timing to it and it made a huge difference at the track. Now it's hurt so I won't get to dyno the stock engine any more before the new one goes in.

What did you end up with for a timing curve at 9 psi?

guyp

The cam was in the motor when I got it and I couldn't find any info on it with the numbers stamped on it so I measured it 209 int. and 212 ex. @.050.

The timing is at 36* from 3,200 up no boost and as soon as boost is seen, 23* at about 3,200(about 4-5psi) and finished at 26* at 5,500. Its around 24*-25* at 4,800. Any more timing and the knock sensor was going off.

ZZ3Astro

Wow, I really haven't put much thought into my no-boost timing, but it looks like I'm overly conservative on mine.

For the WOT/no boost range I have 23 degrees at 3100 rpm at 100 kpa and 28 degrees at 5500 rpm at 100 kpa. I believe this mirrors pretty closely the stock tpi 8D BIN settings.

At 3100 and 4.5 psi I have 17.6 degrees and for 5500 and 9 psi I have about 24 degrees. At full boost (12.5 psi) I have about 21 degrees at 5500.

So our full boost timing looks pretty similar but you seem to have better tolerance of advance in the 3100 range than I do. Maybe from the bigger cam giving more bleed down of compression. What suprises me about yours is the higher RPM of the torque peak, considering how mild your cam is and the mostly stock heads/cam combo. Perhaps they were feathering the throttle to prevent the kickdown to 2nd from occuring? It just seems your torque peak should be at a lower rpm, in which case it would probably put down a substantially higher number.

Here is my dyno chart of my non intercooled runs: http://mentalsocket.com/Iroc87/irocdyno2.jpg

guyp

It could be the loose converter showing tourqe peak higher when it stops slipping. He didn't go WOT til approx 3,100-3,200 in 3rd.

It amazes me how at 5,200-5,300 and 12psi it only made 280hp. Thats a 56hp drop in 500rpm and 3psi more boost!

As far as no boost timing goes, I did a fair amount of variable speed driving before I went to the dyno and never saw any sign of knock.

Peak power at 4,700 is 9-10psi.

guyp

The more timing you run no boost will have a direct effect on how fast your turbo will spool. Not that big a deal when drag racing as you can power brake and spool it up, but when your street driving its nice to have quicker boost.

guyp

Finally made it to the track last fri. night for a few runs. 1st pass was a 2.8/60ft and 15.3@96. 2nd pass 2.0/60ft 12.96@102 on the rev limiter(5600) in 3rd gear. Last pass 1.90/60ft 12.81@104 on the rev limiter for the last 150-200' or so in Drive. For some reason, it won't shift into 4th gear. I have to leave easy because the tires just lite up. The next step is slicks and figure out the 4th gear issue and I'm confident the car will run 12.5 or quicker. I am very happy for the 1st time out with the car. I thought it felt like a 12 sec. car and now I know.

I plan on going as far as I can with this set-up to see what its capable of and then make a few changes so I can get it to run 11.9's

BANDITSBC

very good to hear. the 700r4 will not go into 4th at full throttle. it's been a long time since I've looked into it but they did have a way to keep it in 4th under about 2/3 throttle.

Just throwing this out there. how bout a different gear to help you leave easier and bring you in at your desired speed. I had 3.73's in my first ta and on radials 1st gear is worthless. the 700r4 has a pretty good 1st gear 3.07 or something. my 2.73's left much better and got me some distance in 1st

freaky

heres a link to help with fixing the wot 4th gear shift problem . hope it helps ... nice runs by the way

http://www.joby.se/corvette/mods/2002-0X02_tranny_wot/

vortec350s10

I did this as well in my trans, but I used very short set screws. I believe the existing holes were just small enough to tap them at 6-32's. You might want to consider an aftermarket 4th gear servo/cover in there if your gonna be doing WOT 3-4 shifts to get more 4th gear holding power on the band. What is done to your trans? It's not all stock is it?