Same dyno I went to before when I just had exhaust.
With 113 vette heads, 1.6 rockers, comp cams xfi268 cam, edelbrock 3704 intake manifold
[plus a few things like torque convertor, aluminum driveshaft, no egr or AIR]

I got 193whp and 300wtq
Im a tad disappointed that it couldent even break 200hp
When they first strapped it on, it was running very rich and made 175whp and 225tq.

When I had it there before I got 269tq and 145hp with just the exhaust on.
They gave me a printout that shows all my dyno pulls from this time and last time.

The thick lines on the dyno graph are from today and the thin ones are from last time. Torque doesent fall off as bad as it did before, and peak hp is all high rpm.

 

Tell us more about your setup. Is this a headers back exhaust? Any head work? How much advance? What does the a/f ratio do through the RPM range. That graph looks kinda funny, it's flat through 3500rpm, hits hard and wakes up through 4200rpm, and then is dead the rest of the way to 5200rpm. Looks like there might be some more tuning to be done.

N/M, found your stuff in your car domain link. Headers, 3" cat-back, I assume run for the dyno w/ the cutout open. LT4 valve springs. Yea, power is way down, it should be climbing all the way up with that much cam. Seems quite a bit off, my 305 puts down power like that with a lot less cam and not so awesome heads. The initial torque hit is probably the converter helping you out some, or did you run it locked? I'd be real curious about the a/f ratio. Do you know your compression ratio, or at least the combustion chamber size, I'm assume they were machined down to work well on the 305.

 

No head work, they are the same cc size as 305 heads. I think they guy who had them before me had them very slightly ported.

The convertor wasent run locked as far as I know. Just 3rd gear for the 1:1 drive ratio. I dont have the a/f ratio sheet. But they have it all stored on there dyno. Ill email them this weekend, see if they could email me a copy and ill post it.

Its running a lot better, but yeh. I expected more along the lines of 220hp maybe 240hp and 300tq or something like that.

 

That thick red line looks more like a "dyno spike" than a true reading, but going from 269 RWTQ to 300 RWTQ sounds reasonable with your mods. Sure is a funny looking graph though.

 

Dont think its a spike. It was running real rich down at low rpms, so they corrected all that based on the AFR readings they got. Also the last run was with the cutout opened on my exhaust, so maybe that added a little bit.

 

I agree that more tuning is needed. with a cam that big and with those heads you should definately see the power you were hoping for. On a another note, how does the car feel with the 3000 converter?

 

Using the same dyno for the before & after comparisons was good. From here I see a substantial increase in power. Nearly 60 HP at the wheels over a wide RPM range. From 3200 RPM up to 5200 the power keeps increasing. Where prior, 3200 RPM was the peak HP point.



Need to remember that it is just a dyno, what the car does when there is asphalt under the tires is what really counts.

Once the fueling was in line did you get a chance to play with the spark timing?

RBob.

 

Dident really get much of a chance to play with the spark. But cant spark be adjusted on the street? Just add spark until it knocks? I just dont have wideband so I was more focused on getting the fueling good.

And the 3000 convertor is very street able actually. I dont really notice a huge difference in drivability.

 

IMO it is in serious need of tuning work. I think it's probably still very rich.
How were you adjusting the AFR?

 

Without a WB the dyno was a good choice for AFR setup. Getting the SA correct isn't as easy on the street. A track would help, while a dyno can ballpark it quickly.

The '113 heads are timing limited. The engine will get rough before detonation sets in. With the 369 module shoot for about 26 - 28 degrees BTDC at WOT.

With the higher stall utilize the launch mode SA to get the car hooked and moving (from a stop). Add enough at lower RPM to quickly bring the engine up against the converter, then reduce it to prevent blowing off the tires.

I think this was covered in another thread, but just to be sure, the spark plugs for the '113 heads are 3/4" reach with flat gasket seats. Such as the Autolite 3924 plug (a decent choice). This is different from the stock L03 plugs.

RBob.

 

From the research I have done on the "113 or ZZ4 heads the best choice for a plug is the FR5LS plug. Both SDPC and PACE recommend these plugs as they to have the 3/4 reach and gaskets. I myself am not to big on autolites. Everytime I think of them I think of F O R D. yuck.....lol.

 

Wow, I used the regular AC delco spark plugs for the stock L03 ...... That could be hurting me a lot you think?
Thats for bringing that up!

 

Autolite is owned by Honeywell. The AC Delco plugs are OK, but the shells are weak.

RBob.

 

It'll make a difference. Mostly at lower engine speeds. Make sure that the engine is cold (room temperature) before R&R'ing the plugs. Use a thin coat of anti-seize on the threads. Don't over-tighten, but at the same time make sure that they seat.

Dependent upon how much carbon has built up in the threads it can be difficult to get the plugs to fully thread in. Backing them out a bit and threading back in helps when they get tight before seating. Give yourself time to do this and don't rush.

Note that with the long reach plugs the spark timing requirements will change. Less timing will be needed.

RBob.

 

I plan on changing the spark plugs probably on Wednesday. I checked out the tune they did at the shop, they dident even touch the SA tables. All they did was adjust the VE tables.

I plan on calling them up and complaining, ive had them do a bunch of little things on my car, so hopefully theyll give me at least a discount or a free hour on the dyno so they can tune the SA tables.

For the SA tables, all you do is add spark until it knocks or loses power and then back off a little bit? Correct?

 

I called them, they said they did change the SA tables and it must have not saved or something...... But he said he remembered what he changed and he could take a look at it.

I uploaded the BIN if anyone wants to take a look at it.
Just remove the .doc at the end of it and itll open in TunerPro just fine.

Once I change the spark plugs, ill post up a datalog. I think the VE tables should be good. But maybe some of you guys can send me some SA tables to try at the dyno, I think ill get an hour on the dyno later this week and see if I can get better dyno results.

 

Thats what I do. After adjusting SA I do some VE learns, then same thing all over again SA and VE learn.
Then the "EGR-BPC multiplier" to get the BLM to 128.

This may help a little
https://www.thirdgen.org/forums/diy-...o3-lt1cam.html

If you have the chance to drive it around and play with the tune before going back to the dino, I would not hesitate.

 

My gut feeling seeing the dyno graphs is that theres still some major adjustments that need to be done. The power isnt too bad, thats like 240 at the crank, but you can definately make some more. If you look at some of the torque curves, they have large dips in the middle, giving the look of the engine having two torque peaks. I would recon that the area where the dip is is likely where the spark is off, or the fueling is off, or some other issue.

One thing to keep in mind with timing is that its not about having lots of timing, or 2 degrees everywhere before it goes into detonation. Its about having the right ammount of timing. The goal of the timing is to light the fuel early enough so that it has time to completely burn by the time the piston has gone slightly past TDC. The burn rate is dependant on many factors, such as the chamber shape, cylinder pressure, AFR, etc. The only way to find it is to use a dyno and ajust the timing until peak torque is reached through the torque band. At this point, it does not look like the engine is there yet.

If I where doing the tuning, I would first hook up the wide band, get the VEs in line as much as possible, and then work on the SA. The best way to do it would be to tank up on premium and vary the WOT timing until I find the timing that produces the best torque everywhere while adjusting the VE as needed to maintain the correct AFRs. After that, repeat the test with regular gas and make any needed adjustments for the change in fuel/detonation prevention. After that, make tweaks as needed once the car is on the street.

 

except I would use 87 octane
Just by the look of the dyno curves it does look like it needs more tuning work. I think it has a bit more power in it, especially above the torque peak.

 

Well I changed the spark plugs. The ones I had in there before only threaded in about half as much as the new ones, but when I changed them, I dident notice a huge difference in performance, just smoothed out acceleration a little bit. My friend who helped me change the plugs said ill probably get about 20hp because the plugs I had in there before were barely inside the combustion chamber.
Im kind of sick, but ill do a datalog either today or tomorrow and you guys can take a look at it.

 

Yes, smoother and I bet it sounds different. Once you feel better and get back to tuning, the idle and lower RPM areas will be easier to tune in. The engine will be more responsive to changes in fueling and SA.

Go back to doing VE Learns with easy driving. What I mean by easy is hold the gas pedal steady. Push it down to accel then hold it there. To accel more move it to another position and hold it. You can run the RPM up along with hitting higher loads.

Even the low load areas can be hit by holding the trans in gear (say 2nd) and running the RPM up. Try it at 1/4 throttle, 1/3 throttle, and 1/2 throttle. For the best coverage push the go-pdeal and hold it's position.

RBob.

 

Alright, I did a datalog on the way to my Diesel Tech class.
This is using the BIN file I posted earlier.

If some one could take a look at it, just PM me youre email and ill send it to you. Its about 12mb and is thus too large to post on here.

Ill send it to you Rbob since you said youd take a look at it a while ago.