dagwood

iTrader: (5)

I gave my youngest daughter a ride in the car during time trials on Saturday. Here's a view from the passenger seat...

dagwood

iTrader: (5)

I made it to the final round AGAIN today, but didn't get the win this time. My car still runs the stock fuel tank, and sometimes after I refuel the car, it will bog after the launch on the first pass. We'll tonight when I got to the fi al round, I was waaayyyy low on fuel. I took a chance and didn't refuel it because I was worried it would bog. Well....it was a little too low on fuel, and when I launched the car, it BOGGED......and all i saw was taillights. The car is getting a fuel cell this winter. (I already have one) Anyways, I was super bummed that I didn't get the win, but laid down super consistent passes all day, and was killing them on the tree. I even had the holeshot on the final round! My best r/t's today were a .004, a .003, and a .002. Lots in the .01 range. Anyways, just thought I'd share!

skinny z

I haven't forgotten about this but time is running out for my own project to at least run under it's own steam before winter sets in. I've been wrenching on it almost every chance I get.
When do you suppose you'll be doing this gear swap?

dagwood

iTrader: (5)

Oh no problem, buddy! Im tossing around the idea of maybe swapping gears within the next couple of weeks....otherwise, it will be over winter, sometime

dagwood

iTrader: (5)

Had a fun day at the dragstrip today! I red lit in the 2nd round of eliminations, so that was a bummer. But I ran a personal best 7.34 in time trials today, and backed it up immediately afterwards with another 7.34. Also had a personal best 60' time at 1.49 seconds. The car ran great all day. I even had my 2 biggest wheelies! 😁

skinny z

Thought I'd follow up the gear swap conversation with another conversation with a couple of racers.
One fellow in particular posted his results in the 1/8th with his 2nd gen Camaro.

"Had to check back on time slips from 2015. Back then my 2nd Gen Camaro was running 7.0X @ 96.xx 1.48 60' 4.48 330' 3150 lbs. at the line. I had 5.13's for rear gear with 28.5 slicks went thru the traps at about 6400-6500 rpm on a really good run with a little more mph from good air it would trip the shift light at 6500 at the finish"

That was all 3 gears.
Another S/S racer I've talked with is building a 3rd gen with his son. They're running a 5.13 rear gear through a TH350 with a 2.52:1 1st gear. Combined that's ~11.5:1. Very similar to the quoted text above.
Seems to be a popular result. The taller tire plays a part in this too.

dagwood

iTrader: (5)

Sounds like a 5.13 is what I should look for. Thanks man!

skinny z

Keep in mind that's 1/8th mile stuff from the 2nd gen guy.
The third gen by the S/S racer is gunning for 10's in the 1/4.

skinny z

One the Speed-Talk members crunched some numbers.
Here's a copy and paste of his entire post.

Ok, so I played with this with the given information in the first post.
1.54 60ft
4.68 330ft
7.37 660ft
91mph 660ft
476hp@6300rpm
28" slick with 3.90 rear gear
T400
3380lbs with driver
First off, I'm unable to to keep it in 2nd gear and it shifts into 3rd before the 660. This is with T400 standard ratios of 2.48/1.48/1.00. Somebody needs to verify this. If he is running it out to 7000rpm shifts, it still hits 3rd before the 660 in Quarter Pro.
Second, it's really hard to find a dyno graph of a 383 with a peak hp at 6300. Most are well below that so I scaled back a 410 until it had 476hp @6300.
Then I had to scale that back to 92.5% of that to get comparable 60ft, 330ft and 660ft times.
With a 4800rpm stall convertor and slippage around 15% and shifting at 6700, the shift rpm drops around 1200 which is too much for a T400.
Changing to 4.56 gears doesn't change the 1/8th mile ET that much.
Changing to a 5300rpm stall convertor with around 9% slippage makes a considerable change, like a reduction of .05 sec in the 60, .25 sec and gain of 1.9mph in the 1/8th. That's with the original 3.90 gears. It could be a stout 7.teen car but it's not gonna make 7.0 without mo powah.
Going to 4.88 gears from there drops 1/8 mile ET by another .01 and increases speed by another .5mph and becomes traction limited with 28 x 10.5 slicks. It really likes 11.5 wide slicks at that point. It'll be out of motor at 1100ft in the 1/4.
So, a custom convertor built for this combo will wake this car up until it runs out of power, which is where it is real close to with the virtual changes.
A dyno sheet would still come in handy to correlate Q Pro with the given data.

Another member posted his Vortec headed 406 results. His is a 2nd gen Camaro.

When I ran my Vortec 406 a few years ago it hit 6.82 in the 1/8th. with 4.10 rear gear and my TCI 8" 4800 stall converter. I'd put more converter in it 1st.

That's two votes from racers that suggest a converter upgrade over a gear change.

dagwood

iTrader: (5)

Thank you!!! A new converter will probably be on the horizon. Also, I did replace the rear gear with a 4.86.

skinny z

You're welcome. It's almost like I'm building this for me! But mines to come very soon. Transmission is being built as we speak and then a new converter. I've been in touch with more than half a dozen converter companies. I know from experience that a top shelf properly spec'd TC can make or break a race car. One Super Stock racer I know puts that at the top, or very nearly so, of the go fast list.
I'll pass your gear upgrade along and see if there's more machinations to come from it.

I don't suppose you have the dyno printout do you? My ST contact would like to use it to correlate with his simulation data.

dagwood

iTrader: (5)

I do have the dyno printout. Trying to find it...

dagwood

iTrader: (5)

I was a little off...it made the most hp at 5,900 rpm's. I didn't have the sheet in front of me before. The shift light comes on at 6,600 rpms.

skinny z

I sent that off to my thread at Speed-Talk. Rick took off further with it and now Mr. PipeMax, Larry Meaux has tossed in his two cents.
There's a lot of data and dialogue. I think too much to post here but I don't think you can see the graphs and charts unless you're a member.
I'll download them and post them when I have a chance.
The thread is here:
https://www.speed-talk.com/forum/viewtopic.php?t=68217
It's a couple of pages and a half dozen spread sheets. It's gets meaty at the end.

dagwood

iTrader: (5)

Yep you have to be a member and logged in to view it

skinny z

In case you're interested in a data overload, this is one Speed-Talk members input and calculations.

Thanks for the dyno sheet. It also raises more questions.
BSFC for a naturally aspirated E85 engine should be around .65-.7, which makes for .65*476 = 309pph of E85, not 680-700. Something isn't right with the dyno numbers.
I can make the trans a 2.48/1.48 2 speed but the rpm at the 1/8th is 7300 and change, not the reported 6700.
Anyway, I can pretty much nail the incrementals with the dyno numbers for the given data with a little massaging and lowering all hp numbers by 11%.
That gives around 423hp which nearly matches the high number from Wallace calculator for 1/8th mile.
Now, just substituting 4.86s, traction is lost due to the increase in starting line ratio. Adding an inch of tire width and reducing convertor slip due to rear gear and it's possible go a tenth faster and maybe .7-.8mph faster.
Feel free to ask questions as there are some tweaks made to "cheat" the program to mimic the data and accommodate improved traction with the changes.

dagwood

iTrader: (5)

My engine was built at Demers Performance and Machine, a high performance engine shop, and the owners have a multi car NHRA team, and they have lots of Wally's. I'm 100% certain there is nothing wrong with their dyno numbers...and one of the owners was the guy that dynoed my engine

To put things into perspective, I ran a modded 2017 ZL1 Camaro on beadlock drag radials, and blew his doors. He was running 8.0's.....and computer calculations would show his hp at like 370, and hes probably double that.

I do, however agree that something is holding the car back. Like the converter.....I don't even know what brand the converter is....it's pretty small, and it's purple??

skinny z

I haven't gone into his assessment although I think it's fair to say that the engine as dynoed and the engine as installed in the car have different outputs.
Did you use the chassis headers on the dyno?
Remember too that exhaust length is a major player in engine power results. It's quite easy to get the overall length in the wrong place and kill the torque.
I've the PipeMax exhaust program and if I have enough of your data engine spec wise, I'll have a look at what the optimum secondary lengths should be. There are provisions in the program for open collectors (with extensions) as well as overall lengths including mufflers. Diameter also. There might be some torque to be found with an easy fix.
Let me know it you've any interest in that.

dagwood

iTrader: (5)

So his assessment would be wheel hp? My engine was dynoed on an engine dyno....so maybe his numbers aren't far off?

skinny z

Not sure although I think it's HP at the crank.
I'll ask.
FWIW, my interest in this is that I'll be back racing again this summer. At least that's my hope. Having conversations like this goes a long way towards my gaining a further understanding of my own car.
Call it racing vicariously through you.

dagwood

iTrader: (5)

We also have crap air here. We get a lot of super high humidity and super high DA numbers

skinny z

I can relate. I used to race at a sea level track in a density altitude sense. Now that I've moved, the DA is approaching 4000' on some days. My on track performance was off by more than half a second and MPH down by 3 or better. That's 1/4 mile.
I use a DA correction factor to sort it all out.

skinny z

Here's the reply from Larry Meaux of Max Race Software (including PipeMax).

ETAPRO5 calculates almost exactly same as Rick's Quarter simulationPeak HP - 422.65 i tried up to 5.38:1 Rear Gearsthe 3.90 Gears worked pretty good 'as is' with current Traction problems + Converter slippage 4.88:1 can be quicker with better Traction + reduced Converter slippage 3.90:1 ET Slip Data = 422.65 Peak HP4.86:1 shows : Peak HP= 431.35 at 5900 RPM • at 300-to-302 Feet distancewith only Slippage = 1.10 + better Traction than the 3.90:1 setup did !

skinny z

Just a follow up from Rick who has obviously checked out your posts here.
You may or may not find it accurate or relevant. But between him and Larry, they see the obvious potential that you're looking for. Both men are men of science. Racers too but very much into the virtual development and are, just like your dyno guys, highly experienced.

The models work from engine hp and not wheel hp. They are also straight physics and equations of motion, which is why Larry's calcs are coming up with very similar results.
Dagwood seems to be a drag racing enthusiast which is fun to see.
The correction factors for the timeslips he has posted on Thirdgen are as follows:
6/16/2023, 7:32pm: 1.090
7/08/2023, 5:54pm: 1.084
7/08/2023, 9:31pm: 1.075
7/08/2023, 10:11pm: 1.068
10/7/2023, 2:19pm: 1.048
Dividing 476hp by each of the CF gives reasonable engine hp for the ET and weight of the car. It also shows a reason for the ET dropping later into the night and the season. Once he figures out what air pressure and burnout time, along with torque arm and shock adjustments are needed to hook with the 4.86 gear, he'll do fine with the way the car is set up. Proper changes to the convertor and sealing the air cleaner to the hood will also help reduce ET without changing its consistency in printing time slips.
Dagwood will figure out how to be a big fish in a small pond once he figures out how to cut "teen" lights consistently. As long as he's having fun, that's pretty much all that matters.

Encouraging words with respect to your gear swap. The proof will be in the results.
Looking forward to your next track action.

Just a quick note about something you probably already know.
One of my last engines made 425 HP at peak. ET's however weren't really there. Having a conversation with a Super Stock racer and his comment was more like I'm making 350 HP!
I was somewhat insulted but then I realized what he was talking about.
To put that in context, I'm might have making 425 HP (or somewhat less after the engine was fitted into the chassis) but I wasn't realizing that 425 HP as I was out of that peak range for a good chunk of the run. If I could have kept the RPM's in a tight 1000-1500 RPM window near (and slightly past peak) I would have been much quicker. My RPM width was closer to 3000 RPM.
The point is, peak HP dyno results are one thing. Seeing that for the length of the run is something else.
That is my objective this year. I've settled on gearing and a transmission (the 4L60 isn't the greatest drag racing transmission by the way) but my hope is that the converter will be that step function change I'm looking for. That and a more powerful engine.

QwkTrip

iTrader: (22)

The trap speeds and engine dyno seem to align close enough.

Just as a benchmark.... Vizard's "128" rule of camshaft LSA enables a pump gas SBC engine with 10.5 compression [and decent heads] to make about 1.4 lb-ft torque per cubic inch. That's roughly 535 lb-ft with a 383 engine.

Looking at your engine dyno, it appears this 13:1 E85 combo is not even close to that. If I were in your shoes, I would be inclined to take a closer look at the engine combo. Might be surprised how much more torque it might make across the board, and a lot more power, with a few changes.

dagwood

iTrader: (5)

Thanks for the info!!!! I'm super anxious to get to the track!

Oh and QwkTripQwit is actually an 11.2:1 engine. Quite a bit lower than what i was told

QwkTrip

iTrader: (22)

Even more reason to look closer at the combo.

For example, during your engine dyno the engine is said to consume 670 lb/Hr fuel. Does that pass the laugh test? Seems like a **** load of fuel compared to Hp figures.

dagwood

iTrader: (5)

With the burnout, it burns about a gallon of fuel in the 8th mile. It burns a TON of fuel for whatever reason

skinny z

This is E85 isn't it?

dagwood

iTrader: (5)

Yes. I run a lot of Renegade E98

QwkTrip

iTrader: (22)

I looked up the Specific Energy of Gasoline and E85, Wiki Link to Specific Energy
Based on those numbers, it appears that E85 requires +40% more fuel by mass (or +30% more fuel by volume) to make the same power as gasoline.

A typical good running naturally aspirated gasoline engine has a BSFC = 0.5 (in SI units),
meaning it consumes 0.5 lb/hr of fuel for every 1 Hp produced.
E85 would be +40% above that, BSFC = 0.70

Your engine has a BSFC = 1.5, as reported on the dyno chart,
meaning it consumes 1.5 lb/hr of fuel for every 1 Hp produced.
That seems insanely inefficient.

Maybe I made a mistake somewhere, but it seems there is MAJOR power gains possible if you can get your engine to run more efficient.

dagwood

iTrader: (5)

Hmmmmm......ill have to talk to someone to try to figure out what i can do!

It has a Quick Fuel E85 850DP carb on it, so i wonder if the carb is too big?

QwkTrip

iTrader: (22)

I'd ask this guy for opinion, @Fast355

skinny z

Do you remember this comment from Speed-Talk?

Thanks for the dyno sheet. It also raises more questions.BSFC for a naturally aspirated E85 engine should be around .65-.7, which makes for .65*476 = 309pph of E85, not 680-700. Something isn't right with the dyno numbers.

​​​​​​You dismissed it citing the shop's reputation.
It may be a problem with the dyno on that day. Or something with the engine that was overlooked at the time.
​​​​Perhaps, seeing as it was dynoed there and they produced the numbers, you could ask.
A couple of questions though. And an observation.
Are you running the fueling system as it was on the dyno? GPH and PSI specifically. Obviously it was tested with the carb that's on it now (wasn't it?).
How about headers? Did you use your chassis headers or ones that the shop had. If it's the latter, what are the differences in spec?
As for an observation, with 11.2:1, why bother with E85 or the racier stuff? There are plenty of pump gas engines with that CR that race. I've been part of several of those.

dagwood

iTrader: (5)

It was dynoed with my carb, but not my headers. It looks like their header tubes are a little bigger than mine. Their fuel pump. I have kept it on E85 simply because I didn't want to buy a different carb and fuel pump. The car was this way when I bought it. And the fuel is a lot cheaper, too

Here's a video of one of the dyno pulls...

skinny z

The E85 makes sense from that perspective. I'd have done the same.
As for headers, between what you have and what they have could be a night and day difference in torque output. They obviously have a short collector extension on theirs. You have pipes and mufflers to the axle. That's a significant difference in length and the tuning of yours may be killing the torque.
One of guys that contributed to my Speed-Talk thread about your car was Mr PipeMax himself, Larry Meaux. The guy that wrote the software that everyone uses to determine, among other things, the optimum header spec. As racers, one we can change with relative ease, is the exhaust beyond the 3-bolt flange. There may be something in there for you too.
As for the BSFC, there's something strange going there as was pointed out (here via QwkTrip and at ST).
You might owe it yourself to give your engine dyno guys a call.

skinny z

One more thing.
​​​​​​From a carb tuning point of view, you might benefit from an O2 sensor and wide band AFR gauge.
Then there's no guessing.

dagwood

iTrader: (5)

I should have specified that since this engine was built, I have been running open headers. They have the flange on the ends and I have those little header mufflers on them. They don't do much..

skinny z

That might even be worse but the facts can't be known without some investigating.
I've an old copy of PipeMax. If you'd like, I can run your numbers and see what the header secondary diameter and length should be.
Something else to consider is how the muffler behaves with respect to what it presents to the collector flange. Some, like a Flow Master chambered muffler, reacts somewhat like open atmosphere. The result is a very short secondary which is almost exclusively a torque killer. I've many memories of driving my fresh builds to the muffler shop with open collectors. They were absolute dogs at any RPM below 5000.
Other mufflers, like a glass pack, behave as an extension of the header secondary and add length overall. That's generally better for TQ.
Two entirely different results.

Fast355

iTrader: (2)

My 11:1 383 loves E85, big torque gains compared to 93 pump gas. I also saw big torque gains running the 9.6:1 350 on E85. On E85 both wanted considerably more timing advance, especially at lower rpm to obtain the best torque output.

dagwood

iTrader: (5)

My engine was also dynoed on pump E85. I'm not sure if there's much of a hp difference compared to race E85?

skinny z

That in itself is a very telling statement. There is plenty to be gained from working with the timing curve. The track is the place for that too although not necessarily on race day. That's what T and T is for.

skinny z

For the record, this is what PipeMax specified for my exhasut. Header primary diameter and length and the same for the secondary/collector. Full exhaust lengths are also included although as mentioned some of that length is muffler specific.






On race days (as it'll still be streetable) I'll test the 18.5" open collector. If I can get proper muffler data, then maybe 36.9" with a glasspack header muffler. That is if the data supports the glasspack behaving like an additional length of open exhaust pipe rather than open air.