Weather permitting...I'm going to run the car that has taken me forever to get ready on friday at Coastal Plains drag in Jacksonville/Richlands NC. 406 11.25 compression, ZZX cam, LE ported AFR 195 heads, LE ported HSR, longtube 1 3/4 headers into 3" exhaust with 4" cutout (only 6 RWHP more) Vig 3200 stall, Performabuilt 700R$, Summit 15x8 star wheels with Hossier QTPs, Summit 15x3.5 skinnies with M/T Sportman skinnies, Lake shocks/struts, 4" tube intake. Dyno came back at 406 RWHP and 442 RWTQ.

 

That sounds awesome, get a video if you can!

 

weather is calling for rain when the gates open. With the QTP's I am NOT risking it. Learned my lesson years ago when I crashed the 89 Formula with MT ET streets. It can wait.

Any opinions on what it will run? I think its capable of low 11's, I doubt I will get sub 11.5X shakedown pass or even first day. Any opinions welcome. Mind you, I havent been to a track since 2008. I never launched with skinnies. And this car is a buttload more torque than the last time I was at the track.

 

 

Man that Dyno HATES your car. That's super low for that kind of combo. I'd be expecting closer to 500whp. How much HP is the Auto and Rear-end sucking down.

The Trap speed will tell the real story though.

 

Congrats! That's going to be a fun combo and I'll bet you're really looking forward to driving it this summer!

Making 500 RWHP in the real world is a lot harder than you might think...

 

Should def go low 11’s sorted out. Id probably run 3600-4000 stall for more drag race, but your torque is strong in the 3200-3600 range. So it should 60 well. Assumin 3400 lbs plus or minus

 

this is true! I did some reading here and on ls1tech, it seems vigilante stall converters suck the horsepower out but adds so much torque.

i did also look at a few other who had this combo of Miniram/lt1 intake/her and either 383 or 406 the zzx and all of our heads flow within about 4cfm of each other. One guy on a corvette forum added e85 to his combo and got to 440 rwhp, he was previouslt about 420ish rwhp
Bruce Hawkins did a 383 zzx on a 6 spd and got 440 rwhp on a Dana 44 rear end. He then switched it to LS1.
946spd has this in a th350 400 or 383...dyno read 375 rwhp on Victor Jr and I think stock rear end.

I was a little disappointed in the hp numbers but that torque definitely puts a smile on my face. I'm gonna guess I'll trap around 116 instead of 118 to 120. Vigilante converter is definitely alot looser than my old Edge converter.

 

i have flashed the converter in the street.. and although precision industries says it's a 3000 to 3200 converter it flashes to a hair under 4k. I debated on keeping my Edge converter but decided since I got brand new engine and nearly new everything, might as well get a new converter.

Edit: the str on vig is 2.53. Iirc the str on the edge was 2.4X

If i was young again and street racing on the weekends like a dummy, I would probably have kept the Edge. If i get a wild have I might slap the old converter on, throw it on the dyno and see how much it changed the cars performance

 

Are you able to lock the converter on the dyno?

 

That was locked. Didn't help much

 

I've a couple of questions regarding this cutout comparison.
Where was this cutout located? From the description, being a 4", I'd guess it was after the Y-pipe?
How did you figure out where the cutout should go?

 

cutout is approx 6 inches or so from the merge. being as it would be silly for the pipe to neck down to 3" and then back up to 4" for the cutout, this was the logical choice.

 

When I asked about the 4" sizing, I was referencing that being 4", there's probably a single cutout.
Something you may be aware of and something I'm educating myself on is the placement. Cutouts, for the greatest benefit, are located on each side and are specifically placed a certain distance from the ends of the primary pipes. This will result in the exhaust creating a pressure wave at that opening which is timed to arrive of the exhaust valve as the appropriate time. When the length is correct, the timing is right and this will introduce a negative pressure when the exhaust valve opens thereby creating a suction on the combustion chamber. Should the cutout be placed at an incorrect distance, there can be a negative influence with respect to the timing of the reflected pulse and torque would be diminished.
You may have had the occasion where the car is driven with completely open headers (such as I've had to do when making the trip to the exhaust shop to complete the system). Torque is way down at low RPMs. Quite noticeably too. That's due to that pulse being poorly timed due to that very short collector.
Anyway, what I was getting at was in reference to your only 6 RWHP more. The cutout would have relieved some back pressure in the system however it equally could be causing problems with any pressure wave tuning that may have otherwise occurred with the cutout(s) placed in a more strategic location.
That said, 400+ RWHP is impressive enough to me. Well done.

 

I have read those article, however, our cars are not known for sitting high off the ground, nor is the undercarriage forgiving for our exhaust. I worked with what I had. I thought about dual 2.5 inch cutouts but the collector is the lowest part of the exhaust. My cutout is also electric and would have gone electric for dual cutouts...didnt want to risk it.

 

Understood and that's something I'm wrestling with now.
I'm trying to make a swing to a more track orientated car and open headers are high on the list. Electric cutouts would be a sweet deal but, like you say, it's crowded under there. I hope to be able to go with the old school 3-bolt caps and uncork it on drag racing days.
Looking forward to your track results too.
Good luck.

 

If you're drag racing then a slow moving actuator is fine - you can be loud all the time and nobody cares.

But if you're on the street then it is nice to have a fast actuator that can move almost as fast as your foot. The "active exhaust" valves on newer Mustangs and Hellcats and the like use a Kuster valve that can be operated by a PWM controller. These can be scrounged from junkyard, and get a dirt cheap controller and run the valve manually. Or you can run it with an engine ECM that has PWM support (Holley HP/Dominator for example) and make it function automatically like the OEM setup.

It's one of those things on my dream list that I'll probably never do because, as mentioned, exhaust packaging is nearly impossible. As is I already rip apart V-bands and dent my exhaust occasionally on who knows what. I just had to replace a V-band that got destroyed, and I can't even remember when or how it happened???

 

That power curve looks odd - to have peak HP at 6500 or so and not match or exceed peak TQ is the sign of an issue - something like fuel or valvetrain.

 

Doesn't look odd to me. That looks like a torque converter to me doing torque multiplication with slippage.

And engine like that, with that size cam should make more power than torque. To me it looks like converter wasn't actually locked as requested and because of the slippage creates the massive landslide torque curve.

 

How are you able to manage that?
While I have a toggle switch in the TCC circuit, it's only there to disable the lockup. Application (in my case) is through a 4th gear applied switch in the valve body. This is a built 4L60 and TCI converter.
The only way I can see it being accomplished otherwise is a rewire of the valve body circuit so that manual application can be created via another toggle switch. It'd be a different story with a 4L60E and trans controller.

Further to that, unless spec'd otherwise (as my investigation into another converter through Yank, Edge and a few others has revealed) is that the single disc clutch generally supplied isn't very happy with full torque application. A triple disc is what I'm told is required. This came about in my quest for O.D. lockup for open road racing. Isn't there a concern that a 450 lb-ft dyno blast is going to smoke it?

 

Tuner programmed chip/computer to do so on the dyno...or he said he did. The more I look at the dyno the more I am inclined to think it wasnt locked.

BUT weather looks great for tomorrow. Need to slap the QTPs and sportsmans on the Jeg wheels. Hope I dont get pulled over....although they are DOT tires, I am risking getting a ticket for having them on the street.

 

Just got back. Ran three times. NGL the first run was just jitters. Ran a horrible 13.1 at 80 something mph...

Runs 2 and 3 were pretty consistent. I am wondering if A. Need to swap that Vigilante converter out for my old Edge. B. I'm missing power up top due to some issue.

I think I'll throw it on the local dyno and see where it is power wise compared to the dyno tune run and go from there.

All and all it was fun going back to the track but leaving disappointed isn't a good feeling. The old 383 with the comp cam 503, hedman 1 5/8 headers and same heads (albeit unported) Ran better at 12.46 at 108 mph

 

Time slip data? 60', 330'. 660', ET and MPH?
Can you repost the race weight?
Tires?
Was the cutout open?
RPMs?

Don't forget the weather of the day. Look up your density altitude at Dragtime News if your track is listed.

FTR: By way of comparison my PB with a 355, small cam, Vortec style heads went the same as your 383 (ET and MPH) at 3600 lbs. 60' was ~ 1.80. Corrected to sea level.
3.73 gear, 700R4, TCI 10" converter footbraked to 2200 RPM. Certainly not a drag car but quick in it's day for a streeter.

 

 

Double post

 

Can you repost the race weight? Unknown. No big weight savings and my porky butt at 240lbs
Tires? Hoosier QTP 26x15
Was the cutout open? Yes
RPMs? Converter flashed to 3600 give or take. Shifted 6500 to 6800.




Don't forget the weather of the day. Look up your density altitude at Dragtime News if your track is listed.


DA 564.53 ft

Edit was the right coastal carolina track.

 

The 12.67@ 102 isn't far off the old school Moroso slide rule. That you lost 2 mph on the next pass might be significant though.
But your dyno results at 400+ RWHP aren't being reflected in your time slips. My combo, at best might have been 420 Crank HP. If had 300 at the tire I'd be surprised. The TH700 is a notorious power eater.
So yeah, you're down on power.
2250' is ideal either.

From a combo perspective, even with the reduced output (for whatever reason at this point) the converter might doing it's job.
What was the shift recovery? 1-2, 2-3? The best Yank we run (all street cars) keeps RPMs no less than 5k down the track. Shift at 6500. See 5k. The 700R4 ratios are less than 4 from 6500 in 1st.
My TCI drops to less than 4k which is miserable.

 

Seems like you get up and running okay but then don't make much power to carry you down the track. Might check if your spark timing has slipped or something.

 

The 1.7 60' tells me that the converter is....convert'n .....That 102ish trap tells the story though; you're making about 300 hp and I'm sure that you're expecting a lot better than that.

 

You shift at 6500-6800. Both shifts? What's your trap RPM? QTP tire diameter?

 

Thats what I'm getting at. The converter can take away some mph but 102...when I was 108 and faster with smaller cam, crappier headers and less cubic inches....something I'd amiss.
the zzx.406 combo is definitely 11 second easy and I'm mid 12s.

 

You know I didn't pay attention to trap rpm. Guess I find out next weekend.

QTP diameter is 26

 

My 1.7 PB flat came out of my converter, gear and tire package. TCI 10" (might flash to 3000 at the track), 26" ET Streets, 3.73 gear.
Two tenths came out of that 60' with a Yank SS3600. 1.5x. Almost a half second quicker overall. I'd expect his Vigilante or Edge converter to deliver that kind of performance. And at 406 CID, there's going to be a ton more torque.

Certainly something missing though.
Trap speed RPM may indicate something.

 

You have the same gear, tire, trans ratios as I do.
102 MPH with a 1:1 trans, 3.73 rear, 26" tire, would be 5300 with 8% slip.

 

Go over the car. Something is seriously wrong. Down a couple cylinders? Check plugs and wires. Timing est connected? Check with a light

that car is down 150-200 hp

1.7x 60 is bolt on L98 territory. And so is 102 mph.

its falling on its face for some reason

 

I changed spark plug wires last week just in case. Ill check timing. On way home, the car at low RPMs was hesitating so I had to keep RPMs higher.

 

I haven't been as active on the TGO boards in recent months, but I am bummed out that I missed this thread until now. I am definitely feeling your struggle because I had a whole journey along these same roads over the past couple years. I have a different induction system than you, but otherwise its a street 406 and I had an Edge 3400 converter for a while. I wouldn't say I didn't like it for the 1/4 mile, but it wasn't giving me the launch I had hoped for. So I swapped over to a 3800 yank converter and started cutting some faster 60 foot times both on motor and also on nitrous. I had planned on selling my 3400 Edge converter, but no buyers yet so I kept it. I am kinda glad that I did, as I might experiment more with it on the nitrous because I think locking it up can get me over 130 mph trap speed, however I will sacrifice the 60 foot and ET. I also had some time on a chassis dyno last year and despite underwhelming numbers, it was helpful in understanding how much power my powertrain was robbing and seeing converter slip vs lockup.

I'd like to read this thread over again and comment more later, but I am curious about how your progress is going along the way so I will check back.

 

I remember we started our 406 journey around the same time. i am thinking itll take a day or two to look at the whole car and see what it is. I know itll be something simple too

 

The TH700/4L60 are known for being power parasites. Heavy internals and all that

It's a matter of public record I think but could you repost your engine dyno data and what you saw on the chassis dyno?
I know not all dynos are created equally or used equally for that matter (chassis numbers can be manipulated as easily as how hard the car is tied down or what tires are used).
But to get an idea of percentage lost would help me in my own analysis. I'm guessing 22%? Maybe 25%?

 

I think it is mostly a myth that locking a converter with a naturally aspirated street engine will make it run faster in the 1/4 mile.
Also, most single disc converters have a clutch that is for light cruising only, you'll ruin the clutch trying to apply throttle to it.

 

100% on the single disc clutch. It's a cruise thing as you say.
The converter will continue to torque multiply as you go down the track so why give that up? It's not the same as at the hit but as long as there's slip, it's happening. You build a car accordingly.

As for the TC clutch: I've had deep dive into what it takes for a 4L60 to go WOT locked in O.D. Short story, for HP over stock, it's a tall ask. My last transmission had the capability but most certainly not the durability to do it.

 

I’ve personally trapped slightly more mph by locking, but never ET’d as well. Ive played with locking in various gears, and power points, and never saw et gain. Ive seen dyno gains for sure

 

Is there no fear of shredding the dinky little clutch under full power?
It's been brought to my attention in my converter shopping that it's not recommended with a single disc arrangement. A triple is suited to that task. Same as in WOT in O.D. (but that's another story altogether).

 

Ive heard that and am not sure. My edge racing converter never had a problem but i only locked it a dozen times or so on my 383 that ran 11.40’s and on my bolt on L98 that went 96-100 mph at the time

 

In the same vein, going WOT locked in O.D. which is what I believe the B4C transmission is capable of, isn't the best idea with engine output greater than stock or thereabouts. The 3rd gen cop cars of the day could motor along like that but the transmission guys I've talked with have a long list of mods to keep the trans alive under those conditions. Not to mention the triple disc clutch upgrade.
I gave up on that notion seeing as an open road event would have that feature as a prerequisite. (Doesn't mean I won't give it a go though).

 

Alright...bringing it back from the dead. Few things wrong with the car. Distributor was loose, the torque converter had stuck fins (began to smell it burning up and vigilante was not helpful at all), and the new injectors were dirty...due to fuel sitting in the tank for awhile.
having someone local re dyno to ensure everything is functioning as it should.

 

woah, thats wild. how did you determine about the stuck fins in the converter? I never heard of that, so I'm simply just curious