Ok guys, have a few questions, but first heres the rundown on my car. I am looking to get into to 10s on the motor with out tearing into the motor. First the car: 1984 Firebird with a 10 pt cage, tubular k member, front coilovers, southside machine bars in the rear, stock springs and shocks, minitubbed, 28 x 14.5 hoosier QTP. ford 9 in with 4.30 gears. car weighs 3000lbs without me. 3160 with me. trans is a th 350, advertised 2800 to 3200 stall but it flashes to 4200rpm behind my motor. Now engine: 355 cu inches, 9 to 1 compression. lightweight crank, crower rods, je short skirt pistons, .520 solid lifter cam, dart 200 heads (aluminum) victor jr. intake (ported) 750 qtf carb with e 85 conversion. msd ignition. and 100 hp nitrous.
car ran 11.60@117 on 93 octane, 10.70@125 with nitrous. Car now runs 11.30 on E85 and i ran out of time to spray it. here my nitrous run http://www.youtube.com/watch?v=O70ewShLG2A

questions are 1. will i gain anything from a trans brake?
2. should i go with a 29 in slick?
3. what spring rate to go with in the rear?
4. anything one elses thoughts?

 

Only way I see this happening is tearing into the motor or losing a LOT of weight (do the first one). You don't have the MPH

 

forgot to mention that the 11.30 was at 121mph, and the short times were 1.57 with a little wheel spin. i know i can shed another 100 pounds by taking the exhaust off and taking out the door bars.

 

Transbrake is only going to help if your suspension is able to cope with the shock. What is the rest of your combo maybe you can change a few things on the motor without having to tear completly into it? What size headers? rocker ratio? underdrive pullies? manual box conversion? There is all sorts of free power just have to looks thru the car

Losing the exhaust may help some

 

have the manual gearbox, i have an underdriven crank pulley, the only thing i dont have is an electric water pump i m sure that can free some power that way, i have 1.5 rockers also and 1 3/4 headers

 

Is this a solid roller or solid flat tappet cam?
stocks rockers or rollers?

Seems like 9.1 comp is low for some good power. good if you want to just run the pump gas.

What head gaskets and cc's are your heads? Maybe thinner gaskets/shave some off the heads. If your interested I have an awsome head porter that I can pm you his info. He can make things really flow!

Is this more street then drag or more drag then street?

 

this is a solid flat tappet cam, i have .027 vortec head gaskets, the heads are 64 cc and the pistons are in the hole .030 I built the motor my friends machine shop and i whistled the motor and its a true 9 to 1 motor. kind of a freak of nature. this is strictly a drag car now. i went to e 85 cuz its cheaper and its different and it made more power off the get go

 

not very optimal quench thats for sure.

I think I would look at going into that engine a bit. There is a lot of power left on the table with that combo.

Maybe just a freshen up and have the block decked, go to a solid roller, and have the heads touched up. That would wake that bird up and would not cost much!

What are the other cam specs?

 

Maybe a better converter with abit more stall and t-brake for sure. get the 60's down more and in the proper DA air, it may go high 10's if you have 121mph now in trap speed. Thats hauling the mail for that combo

It be easier if you bump compression. E85 likes compression. 9 to 1 is a blower motor

 

Just because the converter appears to flash to 4200 doesn't actually mean it's a 4200 stall. It sounds like its a street strip 10" low stall. It meay be flashing to 4200 and locking it self up at 3200-3500 throughout the run. 10inch converters are funny things. Best friends or worst enemies I say.

If you want instant gratification you can add a transbrake and a high stall converter. I believe it would take a bottom 1.5 60' to bring you down to the 10.99 mark. More compression, cam swap and changing parts will give you a bunch more power and MPH but won't garuntee you a good enough 60ft to trigger the 10 seconed slip.

The downside of a transbrake is the T-350 is a weak trans and it can create issues with it.

How did you go from a 11.60 2 117 to an 11.30 @ 121 by switching to E85? 3 tenths and 4 MPH??

 

I have no idea why it gained, but the numbers dont lie. The DA was similar on each night on gas 60ft-1.628 1/8th 7.44 @93.96 1/4mi 11.61 @ 117.87
on E85- 1.574 1/8th 7.24 @96.04 1/4mi 11.32 @ 121.01. the only difference was that track was crap on the e85 night. these times are right off my timeslips

 

3160 pounds race weight and running 11.6 @ 117 mph means you're using 400 uncorrected HP. Running 11.3 @ 121 on E85, you're using 430-435 HP. On both passes, your MPH and ET are making very close to the same numbers so traction is matching the power the engine makes.

At the same DA to get that 10.99, you're going to need to run 124 MPH in the 1/4. You would need to make at least 470 uncorrected HP or get the race weight down under 2700 pounds. Removing 460 pounds is possible but isn't easy. On E85, you only need to get the weight down to around 2800 pounds. The more HP you can make, the less weight needs to be removed to achieve the same goal.

The only other way is to make better use of the power you have by reducing friction and drag. Freeing up and controlling suspension etc so power isn't lost before it gets to the wheels. Going the entire 1320 feet at or near the peak HP rpm.

What's the cam grind?

 

spray it.

 

That's the simple solution but he wants to get there on all motor which is always a nice goal to set.

I'm down on power because of altitude but I'm just about to get an 8 second timeslip on all motor. A power adder would be nice but I don't want to use a power adder for bracket racing.

Starting next year, all my racing will be done away from home as our local track has finally been forced to close. Every track around me is at a lower elevation so that 8 second timeslip should be easier to get.

I'm not sure what the DA was of his best pass but racing at a lower altitude track or when you can get some mineshaft air is another way to get into the 10's. Take your car to Denver and see how disappointing a 1/4 mile run is. Unfortunately racing in the heat of summer never gets you a personal best. Spring and fall are your best times to do it.

 

If your going to get rid of weight, go for the moving weight like some billet specialty wheels and alum drive shaft. I think you could also benefit with full set of under drive pulley and a manual steering box if it's drag only. 70 hp or 460 lbs sounds like a lot and is, but your goal maybe easier if you try to meet each in the middle as well as getting your suspension dialed in.

 

Just re-read and saw you already have the manual box... I'd still go with under drives however.

 

More compression, more cam, and a well matched converter will get you into the 10's for sure. Sounds like your current setup runs great for what it is so your suspension must work well? If you don't want to change anything on the motor you would probably gain the most with a torque converter change but I doubt it would be enough for 10's.

If you want to maximize your combination this is what I would do. I would go to about 11:1 compression with 93 octane pump gas or around 13:1 with E85. Match the new cam to your head flow data, I'm assuming they are well ported and you have some flow #'s. I really like bullit cams, they do a great job selecting a custom grind matched to your combination. Then get a converter matched to the combo and you are there. I know you don't want to dig into the motor but that low compression is a limiting factor for you right now.

 

If you call bullet for a cam talk with Mark! He is the man when it comes to camshafts!

 

A little off topic but has to do with the OP's cylinder heads. Do you guys know if there's a difference in the casting / flow #'s of the Dart Pro 1 aluminum heads and the Dart Iron eagle heads?

Thanks,

 

Head flow numbers for just about every cylinder head can be found here

http://users.erols.com/srweiss/tablehdc.htm

 

Not to get to far off topic but Zac did you take your 91 to the track? just curious what times you have run with it since I was looking at your sig?

 

Still haven't taken it to the track yet. I plan on running 11.7x with it if all goes as planned. Not really sure what it will do though.

 

To the op if it makes you feel better your doing alot more with alot less than I am!!! lol I also for some reason have always felt uneasy taking my car to the track in fear of breaking ****.. One weak link shall be gone soon (10 bolt) Good luck in finding just a tad more.

 

Alot of work,but to hook it consistently,a true sub and tub with a back haft tube frame rail and a coil over four link could actually lower the wt tinning it.You get to set instant centers far beyond any stock suspension mod.
The idea of building more than your goal is so you can hit that number all the time then being able to play the game based on where you are on a pass.Take the light or not.

That said I am talking about the CR too.LOL-come here for the advise as you have and stop reading the comic book articles I.E. hot rod about how great a build was they did on just a low compression SBC.

E85 cheaper??.Yes.Is it VP racing gas??.No-No it isn't.