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Organized Drag Racing and AutocrossDrag racing and autocross discussions and questions. Techniques, tips, suggestions, and "what will I run?" questions.
As the title explains I want to improve my 60ft times. It seems my car is a bit sluggish out of the hole for the times it runs. In it's current configuration it runs 7.9x to 8.0x with 1.85-1.95 60ft. (1/8th mile) at 84-86 MPH on the motor only. The car makes around 410WHP. I'm still working on launch techniques so it's somewhat inconsistent thus far.
Here's the basic set up.
89 IROC "stock" suspension/springs/height
TKO 600 5 speed
Ford 9 inch 3.50 gears
Lower control arm relocation brackets- set on next to bottom hole
Boxed LCA- urethane bushings
Custom adjustable torque arm
Factory sway bars front/rear
Air bags in rear- ~5PSI left ~35PSI right
Sub frame connectors
18" wheels with 265/40 Mich pilot summer tires
I typically bring the RPM to about 2500 and drive out pretty hard but not just dumping the clutch. The track I run has a lot of big tire cars so it hooks up great with usually no spin. I want to keep the car in "daily driver" mode but would make some adjustments if it will help. A dedicated set of wheel and tires is an option but I am getting pretty good traction so far. I don't plan on gutting the car or moving the battery or things like that but am interested to know if there are mods I can do to get closer to 1.7s 60ft times.
Yeah ok operator error, I get it. And frankly, there's a lot to be desired here. One of my challenges is that I don't have many opportunities at a test and tune day at our track since there are a lot of events.
And what tires would you recommend? Now I am not spinning but I am getting out gently. I don't think I have ever had a sub 1.8 60ft and could probably launch at a higher RPM if I have a tire to handle it.
I know you were (and maybe still are) running a similar engine but turbo charged. You're 1/4 mile times were close to my 1/8 mile times but what times were you getting in 60ft?
I saw a chart somewhere that showed "typical" or expected 60ft's for various 1/4 mile et's and the chart also showed the 1/8th mile et for the same run. When I compared my et to the chart it showed I should have a low 1.7x 60ft for the et I am running. It basically showed my car is slow out of the hole for it's et.
Yeah your trap speed is high. Its got power for sure.
My old 383 was doing 92-93 mph in the 1/8. My 60's were 1.52-1.56. It went 7.3's in the 1/8 with an auto. About 400 whp
It's fairly easy to be consistent with an auto trans. Manuals are much different. It takes more skill.
You have power, but cant leave hard because your street tires are gonna spin if you try.
Your optimum 60 foots will come from an rpm leave closer to your peak hp, with a quick slip or with some tire spin with a drag slick. Bias ply is what you need
Something like an et street bias ply. On a 15" rim
Being on 18's, you want a drag radial tire of some sort
Street tires do not work very well for drag racing. The hard rubber required for high mileage use can't get soft enough to provide good traction.
Drag radials or any other sort of DOT slick is really a waste of money. The tires are expensive and even though they have a DOT rating, they are not designed to be run on the street. They're only required if you run in a class that demands a DOT tire. Typical bracket classes should allow you to run any sort of tire. MT ET Drag on a 15" rim will work just fine unless you have huge brake rotors that won't fit inside a 15" rim.
Consider the life of a typical street tire is 50,000 miles or so, the drag radials are around 5000 miles if driving on the street. You would need new tires by your second oil change. Street driving also goes through multiple heat and cool cycles. This dries the oils out of the tires that's required to make the rubber sticky when you do a burnout in the water box. Street tires are designed to not heat up so doing the same burnout actually makes the tires slippery.
Simplest terms. Get another set of rims and install slicks. Leave the street tires for street driving.
The Nitto NT05R sucks didely ucks. Once you experience the traction of a Mickey Thompson tire you will then consider the Nitto a normal street tire.
Being able to run the Nittos as a street tire as well is what I liked about them. Ive heard nothing but good on the MT tire as well. The Nittos worked well enough for me to drop 7 tenths in the 1/4 in a mild street car I had a while back and made enough grip to destroy a stock rear that I hadn't had problems with before.
Thanks for the suggestions.
Yes, gear and tire would help but I do want to stick with the 3.50's for daily use.
As far as tires I am not looking for a dual purpose tire. I have street tires for everyday but want to put some sticky tires on my spare rims.
I used BFG drags before and they did ok but I would prefer a better tire. I have seen where bias ply are suggested for a stick shift so I have been looking at some Hoosier and MT dot tires in bias. Still want to drive to track if possible which is about a 3 mile trip for me so I could probably get away with a slick. I am planning on using my 16" rims if possible and the tire selection is not as great as 15's.
Ideas like disconnecting the sway bar are an option. I have bags in the rear too so I could probably do the rear bar as well but not sure if that would help.
Another issue is probably going to be my clutch if the tires can really grip with a more aggressive launch. Currently running a centerforce DF and it's great for a daily driver and does pretty good at the track. I do get some slippage if I really push the start. Thinking of going to the DFX but would like some suggestions or recommendations there too. I have to be real careful with this clutch and nitrous.
I'm not trying to get on "the list" or anything, just want to get out of the hole as well as possible. The car ought to hit high 7's on the motor and get to maybe mid 7's on the bottle. (1/8 Mile of course)
too much wheel speed with 3.50 gears at the initial release of the clutch. it'll either bog or spin it's ***** off. gear changes will be one of the biggest helping factors. don't fear the gear.
1.85's with a stick shift on street tires, that's really pretty good IMHO. I am working through stick shift traction problems myself. (improved to a 1.8 from 2.2's)
I agree with most of what everyone said above, just wanted to mention getting the right tire height too. I made the mistake and bought 26 inch bias-plys (Hooser QTP's). Tires grip good, but when I switched up to 4.11's I started having problems with traction.
If you decide on the ET streets, make sure you get the bias plys, because they also make a radial.
Something that also makes a difference is track. I found there is a huge difference between properly prepped NHRA tracks and the local backwoods 1/8 mile tracks I usually run at.
Thanks for the suggestions.
Yes, gear and tire would help but I do want to stick with the 3.50's for daily use.
As far as tires I am not looking for a dual purpose tire. I have street tires for everyday but want to put some sticky tires on my spare rims.
I used BFG drags before and they did ok but I would prefer a better tire. I have seen where bias ply are suggested for a stick shift so I have been looking at some Hoosier and MT dot tires in bias. Still want to drive to track if possible which is about a 3 mile trip for me so I could probably get away with a slick. I am planning on using my 16" rims if possible and the tire selection is not as great as 15's.
Ideas like disconnecting the sway bar are an option. I have bags in the rear too so I could probably do the rear bar as well but not sure if that would help.
Another issue is probably going to be my clutch if the tires can really grip with a more aggressive launch. Currently running a centerforce DF and it's great for a daily driver and does pretty good at the track. I do get some slippage if I really push the start. Thinking of going to the DFX but would like some suggestions or recommendations there too. I have to be real careful with this clutch and nitrous.
I'm not trying to get on "the list" or anything, just want to get out of the hole as well as possible. The car ought to hit high 7's on the motor and get to maybe mid 7's on the bottle. (1/8 Mile of course)
That's why I went with the Hoosier QTP, they had bias plys for a 16. At the time Mickey Thompson had a 28 inch 9.5 inch tire 16 inch wheel (which is what I should have bought)
I run NT-05R drag radials as my daily tires. I have 5000 miles on them already and still have plenty of life left. They grip much better than any street radial I have run before because they do use a softer compound. I have gone through a set of street radials in 5000 miles burning rubber all the time, so drag radials for street made since for me.
That being said I have bias plys on my original Iroc rims for the track. I just swap them out when I get to the track. 5 minute job with my battery powered IMPACT.
1.85's with a stick shift on street tires, that's really pretty good IMHO. I am working through stick shift traction problems myself. (improved to a 1.8 from 2.2's)
I agree with most of what everyone said above, just wanted to mention getting the right tire height too. I made the mistake and bought 26 inch bias-plys (Hooser QTP's). Tires grip good, but when I switched up to 4.11's I started having problems with traction.
If you decide on the ET streets, make sure you get the bias plys, because they also make a radial.
Something that also makes a difference is track. I found there is a huge difference between properly prepped NHRA tracks and the local backwoods 1/8 mile tracks I usually run at.
I was leaning toward the 26" tall bias ply tire. DOT or pure slick doesn't really matter though. Most of the 28's are wider and I was concerned about rubbing on the inner fender. How did the taller tire fit? I do have front and rear IROC wheels so there is about 5/8" difference in backspacing if needed.
The track near my house (I can hear them run) hosts a lot of events and there are a lot of big tire cars running on any given weekend. It has a concrete starting line and they spray it down frequently. That is the only reason I can get as good of a launch as I can now. If I leave at 22-2500 and don't shock it there is good traction. I just can't get aggressive or it will spin. I am really wanting to be able to use my 200 shot of nitrous but it's been so temperamental due to traction I can't get any better than 7.8x.
too much wheel speed with 3.50 gears at the initial release of the clutch. it'll either bog or spin it's ***** off. gear changes will be one of the biggest helping factors. don't fear the gear.
You are right on the money here. My trans has a 2.89 1st so it's not too bad. I previously had a 3.70 gear with near identical performance. I currently cross the finish line in 3rd right under redline so I geared the rear based on not over-revving when using nitrous. It picks up about 8-10MPH on the juice. I know it's not the optimum gear ratio for drags but I do drive this car most days it's not raining. I just want to get the best launch I can with the gear I have. If I can get more traction and the clutch doesn't slip, then it should cut better 60's- especially on the bottle. I'm working on my launch techniques too.
I was leaning toward the 26" tall bias ply tire. DOT or pure slick doesn't really matter though. Most of the 28's are wider and I was concerned about rubbing on the inner fender. How did the taller tire fit? I do have front and rear IROC wheels so there is about 5/8" difference in backspacing if needed.
The track near my house (I can hear them run) hosts a lot of events and there are a lot of big tire cars running on any given weekend. It has a concrete starting line and they spray it down frequently. That is the only reason I can get as good of a launch as I can now. If I leave at 22-2500 and don't shock it there is good traction. I just can't get aggressive or it will spin. I am really wanting to be able to use my 200 shot of nitrous but it's been so temperamental due to traction I can't get any better than 7.8x.
I haven't bought a 28 yet. Honestly looking at the 26 inch it looks kind of goofy in the wheel well (too short and too narrow). The tire is a 26/9.5 (https://www.summitracing.com/parts/hoo-17431/overview/). I think a 10.5 or even 11 would fit no problem and a 28 will fit the wheel well better. With a 3.50 gear and 5 speed, you may run faster on a 26. I would sell you mine so I could move up to the 28 if you lived closer.
LG Motorsports sold me brand new Hoosiers for $199 a piece (local pickup), check your local vendors to see if they can beat Summit's price.
I used an online calculator to determine what size tire I would need to redline in fourth gear through the quarter mile estimating my mph. Needless to say I underestimated. http://hotrodworks.net/hotrodmath/quarter.html
BTW I am running identical 1/8 mph at 3724 race weight, with a lot less motor. I think you still have quite a bit left on motor.
For launch you are going to be much more aggressive than that with slicks. I started by launching at 3500. I got faster as I launched at a higher rpm. A little scary but that's why you bought that 9 inch
If I can get more traction and the clutch doesn't slip
Question: Can those two things live together at the same time at 0 mph?
I would think that something has to slip until the wheel speed can sync with engine speed. And I have a feeling the answer to this leads to the need for more gear, as suggested.
I currently cross the finish line in 3rd right under redline
How are you at redline at 85 mph (your trap speed)? That's like only 5K rpm.
Instead of limiting gearing, why not lift the redline through the traps in 3rd gear?
First of all let me say, thanks guys. This is exactly the type of conversations that I hope to have.
IROCMAN7 Your experience with tire size and selection is invaluable. Your setup is close enough to mine to directly relate. Last time I weighed the car it was exactly 3600 with me in it and I have gained weight since (me and the car lol) I have added dynomat and the 9" rear. probably close to 100#. This is a full weight daily driver with T-tops AC cruise sub woofer etc. And yes, launch is exactly why I went for the Ford 9 inch.
QwkTrip No, traction and no slip can't live together at 0. But after the moment of clutch engagement and as the engine reaches torque peak I don't want the clutch to start slipping. Currently, on aggressive launches the clutch will slip too much. At the same time the clutch is engaging we don't want the tires to wildly lose traction. A bit of clutch slip and a bit of tire slip would be ok if it is all manageable.
Your redline estimate is pretty close. On motor the RPM in 3rd gear is in the 52-5500 range if memory serves. Just under my shift point of 6000. When I do get a nitrous run in I pick up 8-10 MPH and THEN I am back up to 6000 ish. Before with 3.70's it would push the rpm a bit more but not crazy high. Again, drag racing wasn't the primary reason for the gear change. It was mostly for daily driving that I went for the 3.50's.
I don't have access to the dyno program so I can't post a great graph but here is a shot of the dyno sheet itself. I hope it is legible.
I am not familiar with that term so probably none.
I have the factory type master/slave with a fork. I have upgraded the master with a metal housing and adjustable rod with a braided line to the slave.
The clutch is a Centerforce dual friction and the trans is a TKO 600.
Until now my method is to not slip it any more than necessary. Data logs show I leave at 22-2500 and it pulls down to ~1800 upon engagement. Then it's just WOT from there.
03-23-2017, 11:41 AM
