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Discussion Starter · #1 ·
Some of the guru’s in here probably can help I think. Last year I had a set of 1 ¾ primary headers with a set of turndown’s on the car (402ci lsx motor, 13.5 to 1 compression, 11 degree et head, fast 90 intake, mid 240's duration hydraulic cam, simple Nos plate 150 shot, 4.10 gear 28 inch et drag) and this year, with the same motor, I changed to a set of 3.73 gears, put on a set of 1 7/8 stepped to 2 inch header with a 3.5 collector, but added an exhaust which consists of 3.5 inch piping and 2 flowmaster super 44 mufflers, and some added pipe to exit the car out the sides.

Problem I’m having, is the car went 9.6 @ 139 last year at atco in late November, and now I can’t seem to get it any better then a 9.8 to 10.0 with the same hit of nitrous.

The car last year went in the 6.teens to the 1/8th this year with the same converter it wouldn’t do any better then a 6.25.

We thought that the converter might be bad, so we changed it (old one was shot) and went to a little tighter setup and it’s still doing the same 9.8 to 10.0, but the car’s only in the mid to high 6.3 range now, but the mph has picked back up into the mid 137 range.


Motor leakdown/compression test was fine nothing going on there. Could the exhaust really be choking the car back that badly, or could the sway from a 4.10 to a 3.73 gear really kill the car that bad? Even with the exhaust, the car is 170 lbs lighter too this year, which made me think that I should have been able to see a 9.6 to 9.5 even in the heat of summer. Granted I haven’t been back to Atco with the car, but I have been to 2 different tracks and both places I’m seeing similar performance (lebannon valley in Ny and yesterday Island dragway in NJ)




Any feedback would be appreciated, I’m about ready to toss a fogger on the car and start hitting it with 200 rather then the little Nos plate that goes behind the TB on the fast ls1 intake because the new converter and gearing are certainly are more aimed for a bigger hit, but I’d really like to see or have a better idea as to what’s going on with it the way it sits right now.

Thanks!
 

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$carface
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My personal opinon, throw the flowmaster super 44's in the trash and tune it again with bullets, or something with no restriction and see what it does. I know of a couple of people with no other change then taking the flowmasters off and re-jetting, up to around 3 tenths on some harder hitting street engines. Seems like on low compression smaller engines we don't see much difference, but with bigger ci, more comp, and especially N2o. Get rid of the flowmasters and give it a try.
 

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Discussion Starter · #3 ·
We checked the tune with the exhaust on the car and believe it or not the a/f on the dyno was right about where it was last year (within .1) which I thought was a little odd.

After the E-town Pinks Allout I'm gonna rip it all off and just run open headers on it and see what that does.

I'd love to see that be 3 tenth's, but I dunno, We cut the ends off the mufflers and welded 3.5 inch pipe in and out of them, so the piping is almost as big as the muffler case. But, at this point I'm pointing to the exhaust.
 

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EFI/N2O JUNKIE
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I know all motors and combos are difrerent, but here is what I found on my own car.

Trying to finish my liscense passes two years ago kept going 10.0x @ 136+, couldn't run 9 anything, even with the trans brake (which did nothing for my car!)

Went to E-Town on a Wednesday night, ran 10.03. Dropped the exhuast (dual 3 1/2" Flowmasters, don't know which ones, theyr'e about 6 years old now, turn-downs right after the outlets). I picked-up .01, went 10.02 and 10.01 that night after taking 40 pounds off the car!!!!! The A/F barely changed!

Put Nitrous on the car and here I am now. Went 9.4's that same week on a Friday night with a plate and a .047N jet with the exhuast leaving at 1500rpm.

This is a 414 SBC, 14.8:1 bracket motor, low 10's in decent ait in a 3300lb F-Body. Dropping my exhaust does nothing except give me more ground clearance and limit when I can race the car.

Like I said, I don't know what series these Flowmasters are, they are about a foot long or so, here's a picture:

 

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$carface
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I like the top ten race series(for race engines), just not the street mufflers(on race engines). I agree every car is different, Just in his case, he changed some things and the exhaust was one of them.
 

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Discussion Starter · #6 ·
I'm also wondering that with the times I got out of the car last year in late november at atco, how much should I have lost just from being at atco in november compared to summer time at island and lebannon valley.

I took 170 lbs out of the car over the winter even after adding more cage and exhaust, so I would have thought that would be enough to see similar results in the summer but with the exhaust and gear change, the car hasn't been all too happy.

I was able to get my lic runs done with it, but it's fighting me to get to 9.40 ( I want to run the 9.5 index classes)

It just seems like it should be going better, last year it was a consistant 10.5 to 10.6 car with the nitrous motor setup with an n/a tune and converter in it, I put a 100 shot to it and it went 9.77, jetted it up to 150 and went bottom 9.6's with it, now in the summer I can't get it back to where it was with 170 lbs out. Car is not at 3330, it was 3500 last year for a referance.

I even went to an elec water pump and took all the accy's off the motor except the alt in hopes of picking up a hp or 2, and that doesn't even seem to have madeany impact at all.

Maybe I'm just at the limit of what the car will do in the summer heat, maybe atco in november really is just a 1/2 second faster, or maybe now with the tighter converter and gear change the car's just asking for a fogger with some 30+ jets in it, I'm not really sure what it is. I would have liked to see the car get to 9.5 with a 150 shot off this little plate, but at this point, that's obviously not gonna happen :(
 

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I wouldn't compare times from Atco in november to times you are seeing now in the heat at other tracks. Atco is a fast track to begin with and in November the air is typically killer. It sounds like you made alot of changes at once which makes it a little tough to pinpoint the cause if it is anything other than weather conditions. The converter being tighter and less gear could have slowed the car down at that power level. You may need to put more power to it to see any gains from those changes. Also in my experience once the car gets into the 9's or better weight reduction dosen't have as much of an impct as it does on a 12 second car. So that 170 pounds may not be as much as you thought it was. I would try running the car without the exhaust to eliminate one variable but I'm not sold that its your whole issue.
 

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if you have last years time slip check 60 foot times and the rest of the slip see where your off but like previous post from then to now was a long time and alot of changes. i would leave car together during winter and spring make 1 change at a time to see where you gain or lose next time if you can
 

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EFI/N2O JUNKIE
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Beginning of this year at E-Town I went 9.87. Yesterday at E-Town I went 10.44-10.50. No changes, just the air. We were at -1000ft on a really off-the-chart day, yesterday was about 2500ft.

Lebanon Valley NEVER has good air!

Island Dragway does at times, but E-Town and Atco are usually faster.
 

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Discussion Starter · #10 ·
I've checked the timeslips, the 60 foot times have been somewhat consistant in the 1.35 to 1.40 back last november, and now. I did have to make some adjustments to get it back after the weight removal, but it's sorted out now.

I did make alot of changes over the offseason, the gear change I made because I was at about 7000 gogin thru the end of the track last fall, and I knew to go any faster it was gonna need the change. The exhaust I added so I could run at e-town and any other muffled events, I was hoping the larger primary headers would offset that the exhaust restriction, but I'm doubting it did at this point.

I just checked the weather at atco the day I was there (november 30th last year) and the DA was -1200, both days I've gone to Lebannon this year the da was 2800 to 3000.

Judging from your times Mike at the same track maybe I did actually pick up some rom last year becasue I haven't fallen off that bad, but I've always been under the impression that nitrous makes it's own atmosphere so it isn't effected as much by the weather.

So if the car went 9.85 this year @ lvd on a 3000 da day, and went 9.61 last year @ atco on a -1200 day, I have actually made some progress in the right direction?

Unfortunately, even if I am ahead the weight loss (as I'm not finding out) isn't a linear thing, at this level it doesn't impact things like it did when the car was slow, and weather even with nitrous still has a big impact to how things run.

This is the first 9 second build I've had, so please bear with me, I'm on a learning curve with all this stuff, I have less experience in my whole body then most of you guys probably have in a pinky finger LOL.
 

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EFI/N2O JUNKIE
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You can make BETTER air using nitrous, but if you were to leave the jetting alone and go from a good air day to a bad air day you're gonna fall-off wether you are using nitrous or not.

By using nitrous you can add some more jet to keep the power where you want it. Sorta like turning-up the boost on a turbo.

I put my buddy in my car to so he could get used to it for PINKS and he went 1/10 quicker and a 1 mph faster than me because he is over a 100 lbs lighter.

Anytime you can take weight out you can and should go faster. Weight out of the drivetrain is always the best. Off the front is good. Over the rear, nope, leave it there! I still run the glass hatch to leave weight over the tires!
 

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Discussion Starter · #12 ·
Yeah, most of the weight I took out was rotating weight or on the nose, here'a lsit of what I did:

Went to aerospace hub stle front drag brakes, and serospace rear drag brakes.
manual master cylinder
Redid all the lines, ditched the abs completely
Ditched all the extra wire
dumped the motor mounts and stands, went to a motor plate
Ditched the power steering
Ditched the front bumper support, put an aftermarket support in ( to be used for fuel cell mount later)

ditched the posi, installed a LW spool
smothed the front spindles and sandblasted the rust off, believe it or not, 2 lbs each
added the front 1/2 of the 10 pt, added the exhaust
moved the battery into the trunk


All that got the car with my 280 lbs in it to 3330 with a 1/3 tank of gas, it was 3500 with a 1/4 tank last year, I wanted to do lw axles but the 12 bolt doesn't really have parts that are strong enough to do that, I wanted to do a k frame this year but ran out of $ for that too. Next up is the fogger, and a 3 gallon cell in the nose so the stock tank and all that can go away. Over the winter while the motor is apart and getting freshened up I will do the k frame while the engine's out, and put a fire system in the car, add a parachute, and ditch the rear bumper support. The fire bottle will be in the trunk so that will make up for the support being removed, I still have the door bars to take out, and I want to eventually rewire the car completely to get all the stuff out of the engine bay, might do a BS3 at the same time if $ allows.

Sounds like I just need to play with the nitrous stuff a little to try to make up for what I'm off, the plate I have really won't flow much more then 150 so I dunno if going up on the jet will help or not. I have noticed that the plug's are reading a little richer now then they did in the cold air. I have one size down for the fuel jet and 2 sizes bigger for the nitrous jet (jetting supplied with the kit was a 63 nitrous/44 fuel) I could try puttina 65/44 to it, or a 63/43 to see what either one of those would do. The timing is only at 17 degrees so it's nice and safe where I'd prefer it to be, a/f I know n/a is 11.7 so it should be fine to play with the fuel jetting a little bit on the jug (we don't spray on the dyno, too many horror stories from doing that)

I'm not looking to get it on the ragged edge, just want to try to recoup a little of what the weather has hurt.

I won't run the car again until I get to e-town for pinks in 2 weeks, maybe for one of the pratice passes I'll put the one size down in the fuel side and see if that helps at all. If it does, maybe go back to the bigger fuel jet and try the 2 sizes up on the nitrous jet.
 

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EFI/N2O JUNKIE
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I'll be there Friday night getting the jetting for set so my buddy can go 10.0's in my car. I can't race it for $$$ since my wife works there, but I can let someone else drive my car. He's a 100lbs lighter than me so it won't take much juice for him. I went 10.12 Saturday in 2200' air with a .036N jet so he would have been 10.02.

See you there!
 

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Discussion Starter · #14 ·
A single 36 jet? that's a really small hit :) If I leave everything alone right now, depending on the weather and the track I'llbe between 9.8 and 10.0, I dunno how many cars are gonna be a ton faster with the muffler rule, probably 1/2 of them I'd guess but who knows.

I haven't been faster then a 9.85 this year yet, so that being said I am not expecting any more then that, even a small jet adjustment isn't gonna make a world of difference.

On another note, will there be someone there filling bottles up? I am hoping yes, it's either that or borrow a couple to bring with me.

If you see a pewter transam, and a sweaty big guy near it come say hello :)
 

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EFI/N2O JUNKIE
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I am hoping that Road Runners will be there for filling bottles, I am calling them tomorrow.

I've been 9.2's @ 146+, but my friend driving the car doesn't have a comp liscense so I'll keep it 10.0 for him. Besides, he wouldn't know what to do with the front end 6ft off the ground!

As soon as I have info I'll post it in the E-Town section on here. The wife promised me that tomorrow she'll have the scoop.

WP. If you're lurking here spill the beans!
 

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Discussion Starter · #16 ·
@ 9.2 you're getting down that's for sure, hopefully if all goes as planned, I'll get the fogger on and make it out at the end of the season before I tear it down over the winter, I'll try hitting it with 250 and see what happens. If the little plate at 150 get it to where things are, and dropping the exhaust off gets me a tenth or 2 (the 60 lbs it will save certainly don't hurt) I'll be happy. Then a 250 hit should push it well past the 9.5 mark, how far, and wether the car will be happy about it, I dunno.

Should be intresting to see what the result will be
 
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