racepack help

hey guys,

Im just looking for some info on our data, we just recently got a racepack so some of the info is still foreign to us as well as the car is new to us, so i figured mabye some of you guys could help.

We run a front engine dragster, quick 8, TD stuff nothing super crazy

526 KB/olds
glide
14-71 high-helix 25 lbs
mag 20/grid with 32 total and -8 at the hit, ramped back in by 1.5
mild camshaft

im mainly interested in seeing if our egts are close, or where they should be. Quickest pass for us so far is 7.12 @ 198

as you can see in the graph, our avg. egt drop off while on the 2step down to 900, then rises to a high of 1100 at the finish line? are we close? the plugs look real happy so we arent to worried. I just have been reading lots on here and keep coming across different numbers so mabye sombody would have some more direct info regarding our setup, thanks in advance for any help.


http://s925.photobucket.com/user/b8er/media-full/Mobile%20Uploads/racepack_712.png.html

 

I am not sure I would say...It "drops" to 900. Anything before the hit, may be throwing you off. It looks like you are on the rev limiter (launch control). That would mean, every 9 or 7th fire is out. Your average EGT is thus effected. Plus you may have such happenings as loading of raw fuel, burning in the pipe, before the hit.

If you look at your egt from the hit...it looks very normal. Pump speed and blower boost increase with rpm, leaning out the motor, it gets a little hotter.

Note that the temperature, is actually just a value!! It is not guaranteed accurate temperature. Use it as a datum. Read the plugs...when they get hot, not what the egts value is and use that for your base line.

Give us the whole sheet. pump pressure, blower boost, individual egt's!

This stuff gets fun!

 

meant to say....NOTE what the EGT temp is when you are seeing the plugs get hot. Use that EGT temp as your new Datum point, as a limit or guage as to how lean (hot) your motor is running.

I have had different egt sets vary as much as 300 degrees, with the same tune up.

 

chutedragger

yes we do leave on a rev limiter/ 2 step @ 4500, wide open throttle, no air control

i know doing so will leave different starting line egt's then other people and is part of the reason i started this thread, im looking for info.
Anybody have a similar set up with ball park starting line numbers?
should we be dropping fuel on the 2 step?

I am also aware that EGT's are just numbers and everybody says to continue to read the plugs which we are still doing, and actually the plugs still look very happy. Again im just sorta looking for numbers for the sake of knowing numbers.

here is another shot of the same run with all EGT's , blower psi, and pump psi

I am not sure how to post the whole file up here so if sombody knows how to do that id be happy to do so and then you guys cane have whatever info you need.


http://s925.photobucket.com/user/b8er/media-full/Mobile%20Uploads/7122.png.html

also i forgot to add, if anybody sees anythind weird, please speak up id like all the help or advice anybody has to offer

 

Where are you taking your fuel pressure reading at? Looks like you have more boost than fuel pressure going into the engine early in the run and not much more fuel pressure than boost late in the run? Is the RPM limit up in the corner of the graph accurate (8000)? If it is and you are shifting at 7,900 you are close to banging off the limiter, if your not already.

 

I'm with RB I think you are on the limiter on the shift, fuel pressure looks low BUT its working, nothing I see scares me, it looks like it spins a little on the shift witch is ok but if its doing that on the limiter if you get it off you may have to make another adjustment on the shift. I do wonder how much blower drive you are running, looks like it has as much boost at 4500 on the 2 step as it does at 8000, just wondering why, we have never ran a KB olds this soft. when we are in the 20lb range on the line we see 35 to 40 at 8000.

 

RB

the fuel pressure sensor is on what would be used for your port nozzels, but in our case is a return due to all fuel exiting the barrel valve on the main exit to go through the flow meter ( which i dont think reads correctly on our racepak)

yes you guys are correct it did just touch the limiter on this pass as it as shifting right where the track transisions from concret to asphalt and there is a slight bump. This is also the reason i have for the spike in DS at the same point.

GT

We are spinning the blower at 25% right now. you are pretty close on the boost deal gt, on the 2 step it makes 22.5 and at the top of first gear, 7900rpm its making 25.1. One thing that im hoping would explain this is the cam shaft in it is a well used, multi-time reground camotion cam from back in the day. I dont remeber exact details but it isnt much over .700 anymore. Before its sugested to get a new one we already have and it will be in the motor once the new season starts.
Would such a cam lead anybody to believe it may be the reason for minimal boost gain? Mabye its just a weak blower? Would the fact we are pulling timing down low have any affect on the blower readings?
I do realize this is all a pretty soft tune up and it is basicly what we are looking for with our combo. we run a pretty tight budget and deftintly dont wanna kill this thing which is the main reason i asked you guys to look it over. We would like to be able to play with the 7.0 pro guys in bakersfield and of course our numbers are right there for that but I really wanna make sure this motor is happy and will live even if and when we turn it up to run some local stuff.

Thanks again for the info so far, i really appreciate it but please keep it coming.

 

You don't have an input shaft sensor, but its looking like your converter is starting to couple at the same point you are ramping the timing back in. The lack of timing won't affect how much boost you are recording, but it may affect your egts. The car looks a little wild down low with the driveshaft spinning and grabbing, I am assuming it shakes the tires without the retard and that is why you pull the timing out? If you would like to make sure that your tuneup is safe, pull the rod bearings, measure them and see how they look. If they measure like new, then your tuneup is as safe as you think it is. Compare your new cam specs with the old ones, if there is a large swing in lift, duration or lobe separation, then you are going to have to adjust your fuel accordingly. Good luck on the cam deal, seems like sometimes there is black magic involved as things dont always work out like you think they will. Ive made head and cam changes before and the car goes faster with less boost. Happen to have a picture of where you are taking the fuel pressure? Kind of confused, on the port nozzles but on the return?

 

You may want to talk with you're converter guy too. See how it "flashes" to approximately 56-5800 and is a bit flat before it lets engine accelerate, you can see it in DS also with a couple bumps of wheel spin. Then when you shift, rpm drop is quite a bit above you're flash stall. So the converter does very little for multiplication to bridge the gear ratio of low and high. Also hits tire hard and upsets, again with bumps in DS. Another indicator to me is the very close DS and RPM at end of run. I'm purely speculating but I would guess you have a spragless 10 or 10.5 converter with a fairly steep low number stator with a lot of window area. I think a shallower angle, high stator fin count would show real improvement in the 330 to 660 numbers. I would also guess you're 660's are mid high 4.40's? The stator change should let motor see a "looser" converter, so engine could accelerate faster through low and recover faster after shift. Just my opinion from looking at you're data.

 

You are correct we do not have an input sensor but how are you able to tell thats when the converter is starting to couple? Is it to soon? to late?
Would you recommend slowing down the timing ramp to try and avoid it from being at the same spot as the converter?
Yes the car is a little evil on the launch and is the main reason for pulling timing, mainly to calm it down to leave the line as we are not on great tracks and secondly to hopefully slow the launch as this thing goes red all the time.


il try to take a picture soon to clear this up. But for now, on the back side of a 'nitro' barrel valve you have 2 outs, one straight out the back, for your hat nozzels and then you have one that comes down out the back, for your port nozzels. We have a flow meter on our car so all the fuel that goes into the motor comes solely out of the top hat nozzel port on the back of the barrel valve. then splits into a Y fitting after the flow meter to seperate for the hat and port nozzels.
Where the originally designed output for your port nozzels is on the bottom leg we have the pressure sensor and a return fuel line to the tank.
hopefully il be able to take a picture for you guys soon.
we just put the sensor there as it was an easy spot to do so. Would anybody recommend having the sensor in a different spot? before the barrel valve mabye?

 

thanks for chiming in here, the coverter has always been a question mark in my mind but i wasnt sure if we would really know anything till we got out tuneup fully figured out. When it comes to the tranny im even more lost then i am with the racepak so any help in that area is greatly appreciated.
We dont have a "converter guy" to speak of really but with the info you have said here i may end up bugging you with more questions. and you are pretty close with the half track numbers. 4.41 i believe. il check the book and get back to you if its critical.

If i can try to sum it up to just the basics of what you wrote , are you suggesting we opt for a looser converter for our combo?

 

Basically, yes, a looser converter but not necessarily a different converter from what you have. A different stator would probably do the trick. Converters are like anything else, there is rarely a perfect out of the box match, You got something, it works ok, looks like it requires a change. No need to start over, If you have questions, you can PM me about converter. Are you running a 1.80 gear in you're glide?

 

okay thanks for the help, and yes its a 1.80 gear

I was talking about all this with some friends today and we started discussing the camshaft change we will be making. was wondering what your guys's input would be.
General thought on our end is that with stepping up to a more aggessive camshaft that we may give up some bottom end power but will gain in the mid to high rpm range, Will this loss in bottom end result in the converter acting like it was looser? Let the motor get a bit more of a run at it ? Would it end up hurting in the mid range where the 1-2 rpm drop will become more critical ?

Of course we are guessing but what do you guys think? It was mentioned above that possibly having a looser stator would help our application but im gonna assume most people will say change the cam first and see how it works then move onto the converter, or would anybody think the converter is far enough off it wouldnt hurt to change it as well as change the cam?

 

Nothing wrong with having the sensor there, we do the same. I am a bit confused though why you would run a return to the tank from here. How is it regulated?

 

here is a picture to help clear it up.
the return is just a highspeed, its regulated with a pill/canister

 

just an update here, was looking threw the log book and turns out we were spinning the blower at 19% not 25% like i thought and mentioned above