Okay so here is the deal the last 3 times I was at the track are as follows.

#1: 13.06@106.6 2.012(60ft)
Base time single 3" exhaust with cutout.

#2: 13.13@107.6 2.083(60ft)
Dual 3" exhaust

#3: 13.06@106.6 1.948(60ft)
Sticky tires

Now the problem I am having is with street tires, I would power brake to around 2000rpm then roll onto the throttle or the tires would spin.

With the sticky tires, I did the same but mashed the gas, had no tire spin, but barely improved in 60ft. It seems like the converter flashed to about 3200 rpm and held there for what <i>seemed</i> like a long time, then the speed caught up to the rpm and I took off like a bat out of hell.

It's a PDQ 3000rpm converter. Does this sound like a tune issue? Converter Issue? Something else I am missing? All I've done to the car since #2 and #3 was set lash and change spark plugs (which I did before #2 also.)

I do have to admit that in my drivers side exhaust pipe next to the collector, has a pretty big dent in it from and incident on the roadway. Everyone told me 3" pipe was too big, so I didn't see it as holding me back from my launch atleast. I can still spin street tires no problem.

Any ideas? Engine in sig.
I was hoping for around a 1.6 60ft and something like a 12.5 time and I can't even break into the 12's! HELP!
-Paul

maybe too high on the converter,you're preloading the suspension, leave at a lesser rpm so the suspension hits and plants the tire better? I leave at 1500 rpms, let the suspension do its thing. I've personally never heard of that converter, who makes it?

Like Bob said, try some different launch RPMs. That would be the first thing I would try.

Then I would disconnect the front sway bar. That should help get the front end lifting quicker

You may want to play with tire pressure too. Since you only mention "sticky" tires and not what brand or type it is difficult to recommend a starting point.

3" exhaust pipe will not hurt you. Contrary to popular opinion, large exhaust pipe size will not make you loose TQ. (too large header pipe and collector sizes WILL hurt you though)

Thing is here guys, street tires I got no traction unless I rolled onto it from the line.

I've got M/T Et Street Radials. I get traction with them. They don't spin. I even had a few friends outside watching and they said it didn't spin. Theoretically since there is no spin I should have a faster 60ft but don't by much.

Tried 18psi (2.0 60ft), 16psi (1.98 60ft) and 15psi (1.94 60ft).

Tried 1500rpm and 2200rpm best seemed to be at a higher rpm.

PDQ is the company. The guy that built my transmission got it for me. www.pdqparts.com

I will try leaving at different RPMS. If I go much higher than 2200 I start to creep forward. I can try unbolting the sway bar but it doesn't seem to be a lack of traction.

i would leave the sway bar on. bring it up on the convertor to about 1200-1500 rpms, then on the last yellow you mash it and let off the brake at the same time.
with a 355 and that much cam and head you really need lower gears. i would say 4.56 gears would work pretty good. don't know how much you like to drive it though.

If you are creeping forward at 2200 RPMs either your brakes are weak or your converter is real tight.

If it isn't spinning then look for more power -- I think your converter or tranny is the issue personally. After re-reading your original post I wonder if there isn't something up with the tranny -- you said it "stayed there" for a while. Which to me makes it sound like the trans is slipping, BUT its really hard for me to tell over the internet -- just something to look into.

Pull the dipstick and check the tranny fluid. Smell it for burnt odour and check the color.

Not enough converter for that big cam.

If you are creeping forward at 2200 RPMs either your brakes are weak or your converter is real tight.

If it isn't spinning then look for more power -- I think your converter or tranny is the issue personally. After re-reading your original post I wonder if there isn't something up with the tranny -- you said it "stayed there" for a while. Which to me makes it sound like the trans is slipping, BUT its really hard for me to tell over the internet -- just something to look into.
I agree,I think it is trany.Sounds like it is hitting the trany too hard with the stickeys and causing it to slip.

Not enough converter for that big cam.
Cam isn't that big- it's only a 273 solid.
UDH calls for a 2800ish stall for it too.
With that converter, you can bring your advance in faster.
You can also have a little timing spike in the 2500 95-100 kpa
range too. GM does it in some of there small cid cars to help launch.
Look for a launch mode post in the stickies on TGO.
Also, with the stickier tires you may have uncovered a pump shot issue.
Or what ever name holley gave to the AE in the 950. Tire spin may mask it on the street.

Your 3200 forever comment makes me suspicious of the trans too.
I hope your running at least a .470 boost valve in it.
And your TV is set correct.

I've been meaning to ask you.
What's your idle vacuum with that cam? It's so close spec wise to mine I'm curious.

Cam isn't that big- it's only a 273 solid.
UDH calls for a 2800ish stall for it too.
With that converter, you can bring your advance in faster.
You can also have a little timing spike in the 2500 95-100 kpa
range too. GM does it in some of there small cid cars to help launch.
Look for a launch mode post in the stickies on TGO.
Also, with the stickier tires you may have uncovered a pump shot issue.
Or what ever name holley gave to the AE in the 950. Tire spin may mask it on the street.

Your 3200 forever comment makes me suspicious of the trans too.
I hope your running at least a .470 boost valve in it.
And your TV is set correct.

I've been meaning to ask you.
What's your idle vacuum with that cam? It's so close spec wise to mine I'm curious.

That's a big cam for a 355...he says he has 3000 stall, but he also says it won't spin up past 2200 under a brake stall. If so, 2200 stall is definitely not enough for that cam.

Holley calls it AE. Idle is in the 62kpa neighborhood in drive. I'll get a log at the track this week and see what it shows, maybe run some tune in there.

I have a total 34deg timing in by 3000rpm. ramped up from idle 28. No TV cable on the TH350, was built by an old school racer by the name of Jamie Fox. Has a stage II kit in it. Shifts real firm.

If I mash it from idle or near, the rpms shoot to about 3200. Though I've never had it just break the tires loose when it hits the stall speed like I was lead to believe a high rpm converter would. It's more graceful about it I guess? On the street I can definitely blaze the tires no problem. Definitely seems like drag on the motor.

So check the pump shot/timing at the track. How big of a timing spike? 36-38deg or more at that 2500 interval?

I agree with Mike. :thumbsup:

Too big of a cam combined with too big heads (200cc) on a 355 cu motor equals no TQ.
What's the CR?

Not enough converter for that big cam.

I had a 355 with a .510 lift and 245*@ .050 on a 108, sportsman heads that were heavily ported, 11.0:1, TH400 with a 3500-4000 stall, and 4.11 gears. car ran high 11's to low 12's. Car was 3250 with driver. I wonder about his compression, gears, and converter.

What about the rest of the incrementals? Maybe you're losing time somwhere in between?

I agree with a lot of whats been said. First of all, make sure the tranny in general is in good working order. From there though, I do agree that a better converter is in order. Check with coan or ATI for example. Gearing...Im iffy. Depending on your tire height, I dont think you would need a whole lot more than what you have. 4.11's sound right for that motor, but I cant be sure how much it would actually be worth going from 3.73's to 4.11's. Get on the converter and tranny for sure.

I just noticed, the duration and lift of that cam is more/higher than the solid flat tappet cam that is in my old .030 over 454 and it runs low 12's in my sons Olds. I know the FI helps with torque, but that cam is too big if you ask me :eek: I've out run many a thumping smallblocks, sound doesnt mean fast, get em off the line and there's not enough room to catch up. The street is no place to test traction, I can smoke my slicks thru 3 gears on the street. With that mph, he is making power on the top end, but has nothing down low, in my humble opinion.

I am no expert but I can see what EMcIllece and Bob are saying about the cam being big , What compression are you running in that motor ? , 112 LSA ?

He's running EFI and a tunnel ram intake.
Which means he can do things in such a manner that would be impossible to do with a carb & mech distributor. He can program any timing value with in reason at any rpm. Think the McDonalds golden arches as one example of a possible curve.
He could stall the motor with too much fuel if he wanted.
He could be rich at 2800 and lean at 3k. And perfectly fine at both points at part throttle. Think total control of spark and fuel. And- he has figure out what is needed. No getting close with an out of the box carb.
His cam is the equivalent of a Ultradyne solid 276/284F12.
It's a NF267/xxxF12. Which calcs out to a 273 if you account for the lash difference. And in the mid to low 50's on overlap. 62kpa is approximately 11" of vac. (In Drive) I have 11" in park.
Suddenly this cam is too big?????????? When he has 3.73 and a 3k stall.

My point is he can have a tuning problem as well as a trans problem.
And in the EFI world. It's usually a tuning problem thats only obvious in hindsight.

Do a search on Launch Mode on Thirdgen.org (TGO). It came in the $8F bin too I think if you want to see the code.
If your were still on TGO, Traxion posted his timing table with his 3500 stall converter. He added a lot of timing on the order of 42* total below the stall point of his setup. That would give you an idea on what to do. His cam was bigger than yours though.

What size is your converter? If it's a large diameter unit, it will be inefficient.
The builder may have put a lower ratio stator in it also. That's one of those things builders don't always like to let out. Cheaper often is in fact cheap(er).

Are you running a WB? What CR? 34* may or may not be enough.

Alright guys here is my dyno sheet from April. The WB was set sensative in the printout. Went from 285HP to 310HP in tuning on a mustang dyno. 34º gave the best power. I lost a little going to 30-32-36-38. The converter I haven't measured but is on the smaller side. If its not a 10" its a 12". Not running a full time WB but used the dyno and a friend's Innovative LM1 unit before the dyno. The converter was about $265 wholesale through the transmission guy. I personally feel the trans is working perfectly, shifts great on command every time. Converter, not so sure of? Trans fluid looks and smells normal. I have a B&M external cooler on it (running through the radiator also) and the trans temp doesn't exceed 180ºF in the pan(verified by pillar gauge.)

The cam was selected by UDHarold with the matching springs. Engine Specs:
Engine Specs

Cyl: 8
Bore: 4.032
Stroke: 3.48
CC: 66
Head Gasket: .015
Head Gasket Bore: 4.1
Deck Height: .025
Flat Pisons: 8.65

Quench: .04
CU IN: 355.47
Liters: 5.825
Static Compression: 9.75
Dynamic CR: 8.108

Cam: Lunati 01-TF80-TF72
239/247@.050
267/275@ADV
.510/.530 Lift 1.5
.544/.565 Lift 1.6
Valve Lash .016 Hot, .018 Cold.
112lsa, 106 ICL(Degreed!)

http://home.comcast.net/~twilightoptics/dynoapril7.jpg

And these are my track times from earliest with this engine to last. #1-2-3.
Again #1 was with single 3" cutout. #2 was with Dual 3" exhaust. #3 was with sticky tires.

#1)
R/T------0.167 -0.304 -0.339
60'-------2.087 -2.129 -2.012
330------5.717 -5.673 -5.552
1/8th----8.738 -8.555 -8.44
MPH-----82.73 --85.06 -84.9
1000----11.299 -11.059 -10.95
1/4 ET---13.446 -13.172 -13.066
MPH-----105.32 -106.95 -106.67

#2)
R/T------0.284 -0.394 -0.279 -0.377 -0.281 -0.148 -0.229
60'-------2.223 -2.193 -2.129 -2.214 -2.083 -2.089 -2.235
330------5.8 ---5.724 -5.693 -5.719 -5.66 -5.652 -5.747
1/8th----8.671 -8.606 -8.576 -8.582 -8.539 -8.556 -8.608
MPH-----85.3 --84.98 -84.78 -85.52 -85.05 -84.03 -85.64
1000-----11.159 -11.105 -11.075 -11.065 -11.033 -11.074 -11.092
1/4 ET---13.257 -13.215 -13.182 -13.159 -13.137 -13.192 -13.189
MPH-----107.52 -106.88 -107.19 -107.69 -107.25 -106.66 -107.6

#3)
R/T------0.494 -0.373 -0.421 -0.666 -0.062
60'------2.091 -2.007 -1.999 -1.948 -1.956
330
1/8th----8.588 -8.516 -8.501 -8.442 -8.447
MPH-----84.68 --84.69 -84.61 -85.03 -84.88
1000----11.102 -11.026 -11.017 -10.946 -10.952
1/4 ET--13.23 --13.149 -13.144 -13.067 -13.072
MPH----106 ---106.15 -105.98 -106.21 -106.34

I should also add, that with each track session, nothing changed (tune/suspension) at the track, except maybe a shift point by a few hundred rpm (not necessarily on purpose.) Hope this helps some more!

Just checked the timing its at 28deg up to 2000rpm 30deg from 2-3. @3000rpm its at 34 across as total. So I can definitely change that.

Here is a clip (8.11MB) crappy quality but you can hear what I talk about when it just kind of "hangs," for a second. http://www.cascadecrew.org/video/pir1.avi PLEASE CLICK SAVE AS!

That pass was the 2nd of the night. 13.149@106.15 ~2.007 60ft.

JMO that sounded like not enough converter.

IMO with the amount of power you are making, the converter stall and rear gear it dead hooks and loads the motor, so when you are accelerating it flashes to stall speed and "hangs" there till the car is going fast enough to "catch up" mine does something similar.

Cam seams slightly large but heads concern me more. Some time ago I ran a 327 in my Chevelle that ran 13.0s at 103. I had 461 heads with minor porting. I went to 200cc sportsman heads and suddenly had a 14 second car. Very unhappy at lower rpms.

What size tires are you running on the street and at the track? A short term fix would be to try out a shorter tire if it picks up you'll know you need more leverage ratio wise. Based on your clip I'd say you need more convertor, and unbolt that sway bar, you don't have to totally remove it... just undo the drivers side endlink, back in the day, that was worth a tenth or two.

No sense in unbolting your sway bar if you are not spinning your tires. I have an 1 1/4 inch bar for the front of my car, it made no difference when I unbolted it. My buddy with a 10.20 Chevelle just put his sway bar back on, it made no diff. when he took it off.

JMO that sounded like not enough converter.

That's what I was thinking too. It didn't sound like a slipping trans or anything.

Any chance you could video the tach when launching or get data from a playback tach?

I'll make a data log on the laptop friday when I go out again.

I don't understand why the heads are of concern? I run ample compression, the cam is matched to the heads and the HSR intake. UDHarold didn't seem to have a problem with it. People also run smaller cams on 200cc heads with this intake. And some run 220cc heads. Also I don't think the pro topline heads actually flow what they say they do. The head intake port matches a 1205 Felpro perfect which matches the Stealth Ram perfect.

Slick is a 26" street tire is about 25". Math says with the slick I technically go from a 3.73 to 3.58 rear gear. I cruise at 60 on the freeway at 3100rpm. I don't think I can go any steeper gear in the back.

I don't think the heads are necessarily a concern, it's just that with the large heads and big cam, you are obviously making a lot of high RPM power at the expense of low RPM torque. Your excellent 1/4 mile trap speed reflects this. I think with a converter better matched to your cam/heads, you are making enough power to run near 12.0 ET.

I can't seem to find my grind anywhere, I know it was somewhat custom but anything close are the voodoo line which I know are hydro but similar cams want at best a 2800 converter. Not to say that this is ruled out, but how can I check this short of buying a new one?

Anyone hear good things about continental?

Still open for more disection!

I wouldnt blame the cam or the heads for poor performance. Yes 200cc heads and a cam such as yours arent a recipe for a torque monster small block at low rpm, but its well matched and should make very respectable power at higher rpm.

At first, I was figuring some sort of drivetrain issue from your initial description. Since you seem pretty confident that the tranny is fine, Id say you could use help in the converter department(I didnt download the video though cause you will have a new motor built before I could download the whole file with the dial up connection Im using right now).

My converter does the exact same thing as yours. I have a 66 gran sport with a switch pitch converter(stock item). It has a variable stator that provides 2 stall speeds. I rigged it off of a 12 volt switch to operate it on demand and it stalls around 1800rpm in normal config, but when I put 12 volts to it, it stalls 3000+rpm. This is a stock design/stock converter from the mid 60's and its very inneficient. It spins the tires easier in low stall mode and pulls much harder once it gets rolling.

In high stall mode, it will just want to slip like crazy before it pulls the car well, and you can hear the engine hang up til the car gets going. It just does not transfer power well to the tires and it wont pull the car well cause its sloppy. Basically, when I use it, from a dead stop I have it in high stall. I mash it and it flashes pretty high. Once the rpm jumps up and car leaps though, I switch it off to bring the converter back to the lower stall and it delivers power to the tires much better. If I made better power off idle, Id never use the high stall feature. But the little wildcat motor with the hoter cam is pretty sluggish below 3000rpm, so its nice to have that converter just to get the rpm to flash up when you first hit it. Once I get the rpm to flash up to where it makes good power, it wont load down when I switch it back to the lower stall speed like it does if I hit it from a dead stop on the lower stall speed. It works more like a bad clutch(the high stall function). Oh well, all that stuff will be out of the car sooner or later for some good chevy power.

I was underneath the car today and measured the difference between converter size and my 168tooth flexplate. The difference was just under an inch making the diameter 2" smaller than a 168tooth plate.

That makes it a what size converter? Seems like it would be big, not as big as I've had in the past, but big converters with high stall are less efficient right?

Looks like that makes it a 12" converter.


Anyone figure more slop in converter because of size/stall... or still that it's just not enough stall? Or both?

I think it's a case of not enough torque for the gear/converter combo. i would consider getting lower gears