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Discussion Starter · #1 · (Edited)
After a bunch of frustration over the last year and half I finally got the car done and had it dyno tuned. I took it to my local dragstrip (MoKan Dragway, Asbury MO) Friday night to finally have some enjoyment from the car. Although I had fun finally getting to make some passes I have to say I am pretty disappointed in the times it ran. Best run of the night was 13.90 @ 99mph
I think there is a lot better runs in the car but not sure what is making it so slow even for it's first time out. Here is the run down on the car, the time slips and weather conditions according to Air Density OnLine. First run was 7:54 pm, second was 8:15 and the third was at 8:49pm

Tell me what you think, where I'm going wrong and where to start for making improvements.



The car is a 1995 Mustang GT, no suspension mods other than urethane bushings in the front control arms and sway bar links. Also haven't done anything to try to lighten the car and I weigh 290lb.

Engine:
Stock block/bottom end Explorer motor. Rebuilt under 5000 miles ago, std bore, reground crank with King bearings, cast rings and ARP rod bolts
The pistons were actual flat top with no dish and four small valve reliefs.
Brodix ST 5.0R heads, out of the box with no extra port work
Holley Systemax ll intake, also untouched ports
Comp Cams XE274HR-12 cam
1.6 Crane roller rockers
30lb injectors
75mm Throttle body
75mm C&L MAF
1 5/8" long tube headers, 2 1/2" pipes race bullet converters, Flow Master super 10 mufflers and 2 1/2" tailpipes to back bumper

Transmission:
4r70W - rebuilt
Raybestos Gen 2 blue clutches
Billet extra capacity forward drum
Hardened intermediate shaft
Kevlar bands
Fairbanks Transaction kit - competition set up
Precision 2800 stall converter

Rear End:
Factory 8.8
4:10 gears
New carbon clutches

Wheels / Tires
17 x 9 front with Toyo Extensa HP 255 - 45 all season style tires
17 x 10 rear with Toyo Extensa HP 315 - 35 all season style tires

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A drag radial or slick will likely knock a few tenths off your 60 foot and maybe a few more up top.

Say get you to 13.5s.. other than that, it seems about right. Calculators say you're making a little over 300HP

What do you want to run??
 

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What pressure in front and rear tires, are you doing a burnout, what is your launch procedure, are the tires spinning on launch or hooking up, do the trans shifts feel crisp and tight, Is the front sway bar installed / connected?
 

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Those times sound pretty reasonable for the combination. A sticky tire could help with your 60' times, or hurt it. I had a car that didn't have enough power, a set of QTP 27×10×15 bogged it down so bad it actually slowed the car. After a 150 shot the car was happy again.
 

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Discussion Starter · #7 ·
. other than that, it seems about right. Calculators say you're making a little over 300HP

What do you want to run??
This motor when I first rebuilt it in 2018 had explorer 40P heads, unported explorer manifold , XE270HR-14 cam and 3.27 gears and it ran 13.80 @100 with a mail order SCT chip tune.
I want to run 12.0's so I can race in the index class at my track. I see enough people claiming 12's with way less parts than this. surely they can't all be liars. 2 different tuners have told me I should easily be able to hit my goal with this set up. I didn't expect to hit the goal 1st time out but barely a 13 is way lower than expected.

What pressure in front and rear tires, are you doing a burnout, what is your launch procedure, are the tires spinning on launch or hooking up, do the trans shifts feel crisp and tight, Is the front sway bar installed / connected?
I honestly don't know exact tire pressures. I did do a burnout, fairly mild and I had to launch pretty much off idle. Trying to stall it against the brakes and it would try roll out with minimal throttle input. The tires were hooked! Shifts are solid tire screeching shifts into 2nd and chirped 3rd. Yes the sway bar is still on the car and connected. The best run was by leaving it in drive and letting it shift automatically. Here are video links from the second run burnout and launch. Sorry for the poor quality, I tried to get my brother to use my new iPhone but he insisted on his crappy 20 year old android.

Burnout Launch
 

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Oof... 12.0s... id get a 18-21 gen 3 10r80 car

They're a tad heavier but make 460hp out of the box.

If you wanted to do it with your car it'd be with either a small blower, or N20 kit.. otherwise 347 or 363 stroker built with a better HCI kit.

18-20 gt is easiest and cheaper probably.
 

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Got some good parts on that car, seems to be running about right for a full weight bolt on auto SN95. I think you're going to find all of your ET in the suspension at this point.

That being said, I'd start removing weight from it in places that is geared towards helping the suspension. Tubular front K-member. Tubular A-arms. Front Coilovers with maybe something like a 14in. 150lb spring. Ditch the sway bar for goodness sakes. Removing unspring weight is highly beneficial. Think: lighter rotating mass...aluminum driveshaft? 17x4.5 lightweight front runners? low drag coefficient 4-piston front brake system? titanium lug nuts? how deep are your pockets? This can go on forever... But its all a combination really. Subframe connectors. 8-point roll bar. What about some polyurethane motor mounts or a polyurethane transmission mount? All little corners in a winning setup need addressing. Suspension pieces that will improve the 60ft like a rear anti-roll bar will inherently lower your ETs. Control arms with adjustable heim joints to dial in pinion angle. You hear about these simple combinations that hit these low ETs but my friend, respectfully, it sounds like you are in a stock chassis SN95. Its going to take sacrificing more amenities on an older car to make it competitive with the newer ones. Now, what rules does your index class have on weight reduction?
 

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This motor when I first rebuilt it in 2018 had explorer 40P heads, unported explorer manifold , XE270HR-14 cam and 3.27 gears and it ran 13.80 @100 with a mail order SCT chip tune.
I want to run 12.0's so I can race in the index class at my track. I see enough people claiming 12's with way less parts than this. surely they can't all be liars. 2 different tuners have told me I should easily be able to hit my goal with this set up. I didn't expect to hit the goal 1st time out but barely a 13 is way lower than expected.

I honestly don't know exact tire pressures. I did do a burnout, fairly mild and I had to launch pretty much off idle. Trying to stall it against the brakes and it would try roll out with minimal throttle input. The tires were hooked! Shifts are solid tire screeching shifts into 2nd and chirped 3rd. Yes the sway bar is still on the car and connected. The best run was by leaving it in drive and letting it shift automatically. Here are video links from the second run burnout and launch. Sorry for the poor quality, I tried to get my brother to use my new iPhone but he insisted on his crappy 20 year old android.
Burnout Launch
Burnout looks good and the car sounds healthy during burnout. The motor seems to labor a little on launch or maybe I'm not hearing it well. How high were you able to get the RPM against the converter and what RPM are the shift points? Looks like Brodix 50 ST can come with 55 or 60 CC chambers, and 1.94 or 2.02 intake valves. What did you buy. Did you buy them new or used and if used were valves and springs checked.

Based on whichever CC the heads are, did you calculate the compression with the new combo and did you have the car dyno tuned after the upgrades? 96 mid 97 explorer had 65cc GT40 heads, mid 97 on had 59cc GT40P but they all had somewhere between 8.8 and 9.1 compression. If your compression ratio is low and / or A/F is too rich or valve springs weak and the combo stops making power at 6,000, you will be be down on power. The calculators say you are now making around 300, maybe a little more. In theory that combo N/A should be able to make 350 or more.

Little things like dropping the sway bar, increasing front tire pressure to 40 and dropping rear to 20 will help some. Also installing HD upper and lower control arms (stay away from the spherical rod type) as well as adjustable shocks front and rear to allow you to tune the suspension some will get you some more.

None of the above gets you to 12.0s, you will need somewhere in the 435+ HP range to get you there. Like others said, Small blower or Nitrous will be required.
 
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BTW
Looked at the Brodix heads on their website. They call for 1250 gasket for intake, the Systemax II has 1262 ports, substantially larger, how did you match intake to heads?
 

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For what's done to the car, the times are pretty normal. Now, something to keep in mind is that going out once in a while will not get you the best time. You need to go consistently and learn the car. Practice the launch, change shift points etc. I don't see you hitting 12.0 with the current setup, but I don't see why a 13 run isn't possible. I think it's definitely capable of a 13.7 @ 103 area.
 

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Discussion Starter · #13 ·
Burnout looks good and the car sounds healthy during burnout. The motor seems to labor a little on launch or maybe I'm not hearing it well. How high were you able to get the RPM against the converter and what RPM are the shift points? Looks like Brodix 50 ST can come with 55 or 60 CC chambers, and 1.94 or 2.02 intake valves. What did you buy. Did you buy them new or used and if used were valves and springs checked.

Based on whichever CC the heads are, did you calculate the compression with the new combo and did you have the car dyno tuned after the upgrades? 96 mid 97 explorer had 65cc GT40 heads, mid 97 on had 59cc GT40P but they all had somewhere between 8.8 and 9.1 compression. If your compression ratio is low and / or A/F is too rich or valve springs weak and the combo stops making power at 6,000, you will be be down on power. The calculators say you are now making around 300, maybe a little more. In theory that combo N/A should be able to make 350 or more.

Little things like dropping the sway bar, increasing front tire pressure to 40 and dropping rear to 20 will help some. Also installing HD upper and lower control arms (stay away from the spherical rod type) as well as adjustable shocks front and rear to allow you to tune the suspension some will get you some more.

None of the above gets you to 12.0s, you will need somewhere in the 435+ HP range to get you there. Like others said, Small blower or Nitrous will be required.
The car feels the best it ever has on the street. I am still surprised it has not had traction issues at the track. But I literally just picked up the car from the tuner earlier that day and don't have any seat time with this new set up..

I could not stall it up any. When I tried the car the immediately pushed forward and I let off to keep from getting a red light. I was leaving of idle, then let it shift automatically, I think he told me the shift was set for 6200 at WOT. The shifter in this car is very loose and easy to miss second and hit drive or even neutral. The slowest time of the three was when I manually shifted it trying to be careful and ended up shifting way late. I have a B & M Hammer shifter for it but haven't had time to install it yet.

The heads I bought used but was told they only had a couple of dyno runs on them. They were very clean and almost nothing on the the valves, in the chambers or in the ports so all I did was leak check them and install them. That was a mistake as one head had bad stem seals and I had to pull it back off and fix them. They are 60cc with the 1.94 intake valves. They weren't planned for this engine. I was working on an all new bottom end for them but COVID hit so I stopped spending money on it. I was one that got furloughed and while not working I just decided screw it. I have this bottom end which should not be bad and all the parts to reassemble it so I threw it together. Didn't think about figuring compression, just dialed the cam, checked ptv and checked the timing marks on the balancer. My tuner said it was pushing a little over 350 to the wheels but I have not seen a dyno graph showing it so I don't know where exactly the peak falls or what the torque curve looks like or if it really made that much.

When I go back I will be more focused on getting the details and will try some adjustments. From what little driving I have done with it so far, I feel like it has a fair bit more in it. If I can beat my buddies 12.98 I would be extremely happy.

I have this set up I was working on but not the funding to finish it yet :p

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Your combo says you should be making 350+ horsepower, but the trap speed says about 300, so something is wrong. Assuming the Brodix heads with 60cc chambers were not milled, your compression now is slightly lower than when you had the 59cc GT40Ps installed (9.0 vs 9.1). If you stay N/A or go the nitrous route, that is low and costing you power. Depending on tune, N/A should be 10:1, maybe 10.5:1 assuming 93 pump gas and street / strip use. If you milled the heads to 55cc (the other Brodix chamber option for those heads) that would get you to about 9.5:1.

However, if you are going to put a blower on it, then your current CR is pretty good. If it were me I would not put that big honking, inefficient Weiand blower on, but that is just me. You could sell the Weiand setup and buy yourself a nice S-Trim Kit.

BTW. How did the Brodix head and Holley intake ports line up? If the Holley you have is a 1262 port like mine and the Brodix are still 1250 ports, that is a pretty big mismatch and in the wrong direction with air and fuel coming down the Holley runners and getting partially blocked by the smaller Brodix ports.
 

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Your combo says you should be making 350+ horsepower, but the trap speed says about 300, so something is wrong. Assuming the Brodix heads with 60cc
For comparison sake my full weight plus a little (Vortech kit, SFC’s, drive shaft loop) ‘95 put down 334 hp at the wheels and it always ran between 80-82 mph in the 1/8. It looks like his was fairly close to the same except for the 74 mph 1/8.
 

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Discussion Starter · #16 ·
Your combo says you should be making 350+ horsepower, but the trap speed says about 300, so something is wrong. Assuming the Brodix heads with 60cc chambers were not milled, your compression now is slightly lower than when you had the 59cc GT40Ps installed (9.0 vs 9.1). If you stay N/A or go the nitrous route, that is low and costing you power. Depending on tune, N/A should be 10:1, maybe 10.5:1 assuming 93 pump gas and street / strip use. If you milled the heads to 55cc (the other Brodix chamber option for those heads) that would get you to about 9.5:1.

However, if you are going to put a blower on it, then your current CR is pretty good. If it were me I would not put that big honking, inefficient Weiand blower on, but that is just me. You could sell the Weiand setup and buy yourself a nice S-Trim Kit.

BTW. How did the Brodix head and Holley intake ports line up? If the Holley you have is a 1262 port like mine and the Brodix are still 1250 ports, that is a pretty big mismatch and in the wrong direction with air and fuel coming down the Holley runners and getting partially blocked by the smaller Brodix ports.
For comparison sake my full weight plus a little (Vortech kit, SFC’s, drive shaft loop) ‘95 put down 334 hp at the wheels and it always ran between 80-82 mph in the 1/8. It looks like his was fairly close to the same except for the 74 mph 1/8.
The car feels the best it ever has on the street, blows the tires off with ease. But the numbers at the track and dyno claim my tuner told me just seems like something is wrong. My mind was think along the lines of tire size, gearing or something in the converter. My tuner did say he liked the converter but also stated since it was a single disc he didn't lock it up except in OD. Comp Cams says I need 3.55 - 3.73 gears so my thought was the lower gear was making the converter slip too much so it is wasting time above the peak power point while not gaining much speed. Or maybe needing taller tires and/or a shorter shift point. If that makes any sense to you. I do have some 27 x 10.5 Hoosier DR2s I planned to put on the next time out. They are well used but good to test my taller tire theory. I also plan to work on the brakes and fix them where I can at least get a little stall on it.

The GT40P setup was little higher compression because I had those heads milled .030" I am not sure what that equates to in volume but on the Brodix head they say .006" is 1cc.

There is some mismatch between the intake port and head port. I did not do any matching on them. I was told the Brodix casting was the same as the Holley Systemax head so I didn't thoroughly check it out.

As for the Weiand blower, I am an old fart and I just like the look and sound of the old school 6-71s. It was not planned to be a max effort set up, just for oh's and ah's at the cruise nights.:)
 

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The cam is tiny
the pistons are stock type and leave a lot of power on the table
the intake is just ok, probably works fine with what you have
the gearing may be ok depending on where the car's peak power is in relation to finish line rpm
traction if it's not spinnin, it's fine

I think the ET is about right for the parts you are using and in that car (SN95's are heavier than fox body cars)

IF it's a street car you have to be careful with mods as it can get quickly out of control to the point where the difference between race car and street car become very apparent and it becomes no fun to drive other than to race it. Trust me. Going through it as we speak. It's all about what you can put up with, and as I age I can't put up with as much as I used to.

To get to 12.0 you're gonna have to let it breathe some more and/or work on weight reduction.

yes drag racing can be disappointing. I've been doing it for over 30 years and I still get disappointed from time to time. I always wanna go faster and have the experience and credentials to do it but as I get older, I get less motivated to do that kind of "work".
 

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Non expert making a blanket statement but it seems like the 170cc headed 302/306 combos were/are all in the 300 rear horse range give or take. @Racer 1966 how much power did they say it made? For the peanut gallery: What does the typical 300 horse sn95 generally run in the 1/4? What sort of mph? 100 or so? Or closer to 105? 99 mph seems on the low end but I don’t know, I’ve never ran down the 1/4. @Racer 1966 the dudes that are running 12’s (high’ish 12’s) with stockish power are doing it with high rpm launches and sticky tires. Basically, they’re beating the dog sht outta it for 12.89 seconds. 😂
 

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This is just for reference.
85 GT daily I bought and threw a few parts I had laying around on.
Rear seat and rear plastics were out for cleaning is the extent of weight loss. I weigh 195
Mods
-Junkyard $50 GTP heads with AP springs.
-Stock cam where they felt like installing it at the factory
-? mile shortblock including stock timing chain (all the wiggle) When I took the heads off there was a nice ridge.
-Air Gap intake
-600 DP QFT carb stock air cleaner and paper filter element
-4.10s
-Stock crunchy t5
-BFG all season Radial TAs 225/60r15
-1 5/8 longtubes into 2.5 H pipe then 2.25 all the way back through magnaflows
I ran 81 mph in the 1/8th.
Your MPH seems low to me at least a 103-105 mph car.
 

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The car feels the best it ever has on the street, blows the tires off with ease. But the numbers at the track and dyno claim my tuner told me just seems like something is wrong. My mind was think along the lines of tire size, gearing or something in the converter. My tuner did say he liked the converter but also stated since it was a single disc he didn't lock it up except in OD. Comp Cams says I need 3.55 - 3.73 gears so my thought was the lower gear was making the converter slip too much so it is wasting time above the peak power point while not gaining much speed. Or maybe needing taller tires and/or a shorter shift point. If that makes any sense to you. I do have some 27 x 10.5 Hoosier DR2s I planned to put on the next time out. They are well used but good to test my taller tire theory. I also plan to work on the brakes and fix them where I can at least get a little stall on it.

The GT40P setup was little higher compression because I had those heads milled .030" I am not sure what that equates to in volume but on the Brodix head they say .006" is 1cc.

There is some mismatch between the intake port and head port. I did not do any matching on them. I was told the Brodix casting was the same as the Holley Systemax head so I didn't thoroughly check it out.

As for the Weiand blower, I am an old fart and I just like the look and sound of the old school 6-71s. It was not planned to be a max effort set up, just for oh's and ah's at the cruise nights.:)
HaHa I'm not young either and grew up with 6-71s and tunnel rams sticking out of everyone's hoods. For visual effect a 6-71 style blower is great, for power in your combo, not so much and it will add a ****load of weight over the nose.

As others have said, SN95's are heavy, much more so than Fox Body's. My 95 Cobra was 3750 with me on the on the scales with A4 block, YSi, 10 point cage 10x28 slicks on rear and skinnies on the front light bogart wheels front and rear. you have to be there or a little more.

You are def down on compression from your old combo. If the old heads were milled .030 and new heads are stock deck, you might have had 9.5" or 9.6" and now have 9.0. The port mismatch between the intake and heads is also hurting power. According to Brodix, the new heads are a 1250 gasket size and the Holley is def 1262 gasket. See pic and you will see how big the 1262 ports are. You should get and post the dyno tune info.

BTW the Holley intake is def not costing you power other than the port mismatch. I made well over 900BHP with the same intake, just flow matched.

You could try the bigger tires next time you go to the track and see what they do. They would effectively give you a higher rear end ratio. Make sure you air down the DRs and air up the front tires.

I was thinking the converter was stalling too low, because you could not brake hold the car much past idle, but I'm not an auto trans expert, so I'll let those that know more on the subject comment on it.

Holley and Edelbrock Vr. Jr with 1262 Gasket.
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