Quaife Diff vs Drag Slicks

[1TireFireTSi]

Hey guys.

I'm making 405whp on an Evo3 16G turbo, stock cams, and E85. Car weighs 2700lbs with me in it. I've got fully adjustable K-sport coil overs. I want to get down to the track when it opens but obviously being FWD, traction is presenting a challenge.

I've never raced at the track before but I'd like to be in the 11s this season. I'll be having the car tuned with boost by gear using my linkv3.

I'm running a large diameter brake on 17s right now and the way I see it I either need to downgrade to a factory rotor and fit slicks on a 15'' wheel or purchase the expensive Quaife LSD differential and run drag radials on my 17s, keeping my current brake set up.

Obviously, the LSD route will be much, much more expensive ($1600 installed for just the LSD) but it'd be a great set up for the street (my DD). On the flip side, if I hocked my brakes and went to a 15'' wheel and slicks I'd save a lot of money and still be able to hook at the track on the factory diff.

I'm sure I'm not making enough power to break the axles or differential yet so durability isn't really my concern at this point.

Anyone have experience running a 17'' drag radials before? Which set up would net the best results at the track?

 

[wishin4nX]

My friend Adam (black_gst) has broken his diff twice with his 20g, once with a slip on LSD. E85,never dynoed but pretty sure he's not at 405whp

 

[1TireFireTSi]

My friend Adam (black_gst) has broken his diff twice with his 20g, once with a slip on LSD. E85,never dynoed but pretty sure he's not at 405whp

Guess a lot depends on how hard you're launching. If I'm leaving at 6 psi in 1st I'd imagine it'd hold up. I've heard the inserts are hard on the spider gears too.

 

[ShadowGSR]

Not to be rude but i dont think your making over 400hp on stock cams and a small 16g turbo. You should get an awd dsm instead of a fwd if you want to race anyway.

 

[SpawnedX]

Not to be rude to the ignorant newbs in this thread, everyone but me and the OP at this point, but 405 WHP on an Evo III and e85 is not that hard.

 

[Detroit Style]

This is a hard one. If the diff in the car is good and not loose enough to the point it only spins one wheel. Id say put a 15" or 16" wheel on it and a tire. That will help as much if not more than a LSD and tires with no side wall. In drag racing, side wall makes the grip. From dealing with the cars I have, everyone wants the sleeper street car look and ran 17"+ wheels with a radial. Only a few ever got the car to hook, regardless of width. You will also want to run the tallest tire you can. For the fact the taller the tire, the larger the contact patch. It also helps out at the big end.

As far as the suspension, a good starting point will be half stiff in front, full stiff in back. Then, go from there depending on how the car hooks.

Tire pressure is also a big factor. Lower pressure will give you more wheel speed in the burn out, giving you better heat build up and more grip off the line. On the other hand, the car will get very floaty at the big end. Higher pressures do the opposite for the same length burn out and make the car more stable.

As far as what pressure to run, ask other FWD guys on slicks at the track and go from there. Remember every car is different so don't take their pressure as known perfection. The Integra I set up at the end of last season, I ran 6psi pre burn out which netted us 10psi post burn out. The car moved you with a 1.7 short time, with room to go in both tire pressure and suspension set up. Not bad for a daily driven, pump gas, full leather interior street car on a fragged Quife.

In the burn out, you will want do the burn out, grab 2nd if all possible to get more wheel speed, then hold it at what ever RPM you do burn outs at until, the tires start to pull the RPMs down. At that point, roll out, and stage.

Once you get out of the box, and stage. Its time for you to figure out your launch point. Remember, there will be a lot more grip than on the street. So, you will need to relearn how to launch the car. Start at 2500 RPM, and slip the clutch. Then go up from there until you find the grip limits, and step down a little.

This will be a learning experience, so I hope this gives you some light into what to do. Last season was my crash coarse in FWD cars. I knew the basics of them, and knew how to do RWD cars. So, I just applied that knowledge to the Integra. Which a lot is the same when it comes to tire choice, burn out technique, and basic suspension tuning.

If you have any more questions towards the beginning of the season, let me know. We are bringing the Integra out on a new set up, and a working LSD. So, Ill be more than willing to give you some insight as I get everything down on a FWD car.

 

[Clinical]

Not to be rude but i dont think your making over 400hp on stock cams and a small 16g turbo. You should get an awd dsm instead of a fwd if you want to race anyway.

Wow if you aren't the most uninformed ignorant person on tuners.
Please, quit posting.. Never post here again until you learn a damn thing about DSM's.

As spawned said, 405whp is very possible on E85 and a 16g and stock cams. My 20g on my talon wasnt much better, and street-tuned by myself on 91 octane I was in the 330whp ballpark on a bone stock motor and bone stock head excluding ARP headstuds and an MLS headgasket at only 22psi.

A fwd DSM is perfectly fine for racing. You are a grade A tool for going around saying get an AWD dsm if you want to race. FWD's are perfectly acceptable and are usually much faster on the street with less drivetrain loss (oh jeeze did I just say fast and street in the same sentence? I bet I have tooners FBI on my trail now) and they weigh less. Some people prefer that.

To the Op:

I'd go with the LSD myself just because one way or another you're going to want it, it's a huge improvement when on the street with just street tires.

However just tires will work .My civic friend managed to run an 11.9@116mph with just slicks, an open diff, and a failing trans.

 

[sax_man]

Honestly you would be best served by getting both, but if you have to choose one I'd say definitely go for the Quaife.

 

[1TireFireTSi]

This is a hard one. If the diff in the car is good and not loose enough to the point it only spins one wheel. Id say put a 15" or 16" wheel on it and a tire. That will help as much if not more than a LSD and tires with no side wall. In drag racing, side wall makes the grip. From dealing with the cars I have, everyone wants the sleeper street car look and ran 17"+ wheels with a radial. Only a few ever got the car to hook, regardless of width. You will also want to run the tallest tire you can. For the fact the taller the tire, the larger the contact patch. It also helps out at the big end.

As far as the suspension, a good starting point will be half stiff in front, full stiff in back. Then, go from there depending on how the car hooks.

Tire pressure is also a big factor. Lower pressure will give you more wheel speed in the burn out, giving you better heat build up and more grip off the line. On the other hand, the car will get very floaty at the big end. Higher pressures do the opposite for the same length burn out and make the car more stable.

As far as what pressure to run, ask other FWD guys on slicks at the track and go from there. Remember every car is different so don't take their pressure as known perfection. The Integra I set up at the end of last season, I ran 6psi pre burn out which netted us 10psi post burn out. The car moved you with a 1.7 short time, with room to go in both tire pressure and suspension set up. Not bad for a daily driven, pump gas, full leather interior street car on a fragged Quife.

In the burn out, you will want do the burn out, grab 2nd if all possible to get more wheel speed, then hold it at what ever RPM you do burn outs at until, the tires start to pull the RPMs down. At that point, roll out, and stage.

Once you get out of the box, and stage. Its time for you to figure out your launch point. Remember, there will be a lot more grip than on the street. So, you will need to relearn how to launch the car. Start at 2500 RPM, and slip the clutch. Then go up from there until you find the grip limits, and step down a little.

This will be a learning experience, so I hope this gives you some light into what to do. Last season was my crash coarse in FWD cars. I knew the basics of them, and knew how to do RWD cars. So, I just applied that knowledge to the Integra. Which a lot is the same when it comes to tire choice, burn out technique, and basic suspension tuning.

If you have any more questions towards the beginning of the season, let me know. We are bringing the Integra out on a new set up, and a working LSD. So, Ill be more than willing to give you some insight as I get everything down on a FWD car.

Awesome insight, helps a lot.

Was the Integra on slicks or radials?

Slicks and drag radials seem to be about the same price wise from what I've read but it sounds like a good 15'' slick is the better bang for the buck.

The car, on 225/45 street tires, is about as helpless as a one legged marathon runner right now so I'm sure either way I go will be loads of improvement. Depending on where my bank account is when the season opens back up I might just try stuffing some slicks under it and running the open diff. I don't like the idea of getting rid of my brakes but without ABS you can only have so much stopping power anyway.

My goal with the car is to have something I can drive street/strip and the Quaife would be effective in either setting; they're just expensive. Either way, I plan to buy the LSD eventually and possibly run that in combination with either my current set up on a drag radial or with a 15'' slick.

By the same token if it were possible to get into the 11s on a 17'' radial I'd prefer that over slicks. Be interesting to see some of the tire combinations fwd cars in that bracket run. I need to figure out if a stocker 15'' wheel will mount a slick or not too. I believe, at least the TSI/GSX/GSTs came with a 16'' wheel though.

 

[Detroit Style]

Awesome insight, helps a lot.

Was the Integra on slicks or radials?

Slicks and drag radials seem to be about the same price wise from what I've read but it sounds like a good 15'' slick is the better bang for the buck.

The car, on 225/45 street tires, is about as helpless as a one legged marathon runner right now so I'm sure either way I go will be loads of improvement. Depending on where my bank account is when the season opens back up I might just try stuffing some slicks under it and running the open diff. I don't like the idea of getting rid of my brakes but without ABS you can only have so much stopping power anyway.

My goal with the car is to have something I can drive street/strip and the Quaife would be effective in either setting; they're just expensive. Either way, I plan to buy the LSD eventually and possibly run that in combination with either my current set up on a drag radial or with a 15'' slick.

By the same token if it were possible to get into the 11s on a 17'' radial I'd prefer that over slicks. Be interesting to see some of the tire combinations fwd cars in that bracket run. I need to figure out if a stocker 15'' wheel will mount a slick or not too. I believe, at least the TSI/GSX/GSTs came with a 16'' wheel though.

The Integra was on a 24" slick. We only got one pass on my base set up before the track closed. It went 11.0x@130 with a 1.7 60' compare to its last pass of 11.34@134 with a 2.3 60'. Again, on a broken Quiafe, pump gas, and full interior.

Radials have their ups and downs. The only real benefit over a slick is, you can run them on the street with out much hassle. The downfalls are, they are a completely different animal when it comes to suspension tuning, and their lack of consistency track to track. On high grip tracks, they are amazing, if you know how to tune a suspension, they are amazing on the street with a good burn out. Again, not in a low profile. Low profiles are worthless.

As far as the brakes go, almost all drag cars run manual brakes, behind a 15" wheel. The stopping power is more in design and pad selection than over all size. Big brakes are great when you need to have repeatability turn to turn. In drag racing, you don't need that. From my world, the majority run Aerospace brakes, or Willwoods. They slow cars down from 180mph+ with out a chute just fine. Again, on manual brakes. Its all in design and pad selection. Do they make great street brakes? The non race only ones sure do, if you're not trying to carve corners.

I fully support the idea of the diff and wheels being the best choice. It comes down to budget and how much work you feel like doing at that given point. Remember, the diff may be $1600 but, is that with install?

Oh, on the slick topic, go with a soft wall tire. It will help prevent breaking parts, and hook better in most cases.

A lot of us around here run the MT ET Drags both on the street and at the track. It has treated us very well. The radial guys tend to run the ET Street or Hoosiers. My car will more than likely end up on a 255/60/15 ET Street, for the simple fact it is a daily.

You will want a 15x8 or a 15x9 wheel if you want to run a 15" slick.

Its possible to dip 11s on a 17" radial, it will take one hell of a driver or a ton of power. And it would be some stupid looking 11.99@200 mph looking ricer pass. ::

 

[nickk90]

if the get the lsd 1st you wont have to worry about your diff exploding with slicks and having to get a new trans
might save u alot of cash in the long run

 

[1TireFireTSi]

if the get the lsd 1st you wont have to worry about your diff exploding with slicks and having to get a new trans
might save u alot of cash in the long run

Good point.

The Integra was on a 24" slick. We only got one pass on my base set up before the track closed. It went 11.0x@130 with a 1.7 60' compare to its last pass of 11.34@134 with a 2.3 60'. Again, on a broken Quiafe, pump gas, and full interior.

Radials have their ups and downs. The only real benefit over a slick is, you can run them on the street with out much hassle. The downfalls are, they are a completely different animal when it comes to suspension tuning, and their lack of consistency track to track. On high grip tracks, they are amazing, if you know how to tune a suspension, they are amazing on the street with a good burn out. Again, not in a low profile. Low profiles are worthless.

As far as the brakes go, almost all drag cars run manual brakes, behind a 15" wheel. The stopping power is more in design and pad selection than over all size. Big brakes are great when you need to have repeatability turn to turn. In drag racing, you don't need that. From my world, the majority run Aerospace brakes, or Willwoods. They slow cars down from 180mph+ with out a chute just fine. Again, on manual brakes. Its all in design and pad selection. Do they make great street brakes? The non race only ones sure do, if you're not trying to carve corners.

I fully support the idea of the diff and wheels being the best choice. It comes down to budget and how much work you feel like doing at that given point. Remember, the diff may be $1600 but, is that with install?

Oh, on the slick topic, go with a soft wall tire. It will help prevent breaking parts, and hook better in most cases.

A lot of us around here run the MT ET Drags both on the street and at the track. It has treated us very well. The radial guys tend to run the ET Street or Hoosiers. My car will more than likely end up on a 255/60/15 ET Street, for the simple fact it is a daily.

You will want a 15x8 or a 15x9 wheel if you want to run a 15" slick.

Its possible to dip 11s on a 17" radial, it will take one hell of a driver or a ton of power. And it would be some stupid looking 11.99@200 mph looking ricer pass. ::

The Quaife for my car runs $849 shipped from Ebay. In addition, I need to pick up a Hyundai final drive gear. Installation is around the $600 range at our reputable DSM shop here.

I'll definitely be getting the LSD in time but it sounds like my first priority should be some meats and 15'' dubz.

Time to price some slicks!

 

[richard33]

Not to be rude but i dont think your making over 400hp on stock cams and a small 16g turbo. You should get an awd dsm instead of a fwd if you want to race anyway.

Coming from a guy with a slow ass fwd Honda that means a lot. I have a fwd, should stop racing it?

To the OP, you should get some nice tires instead of the LSD. I have Hoosier QTPs which are 26x9.5x16 and an open diff and cut consistent 1.80s and some 1.7s. Although not great 60' times, they are good enough to make clean passes and not break stuff. I'm still using the stock tranny and axles. The best part about these tires is they hook on the street too.

 

[1TireFireTSi]

Coming from a guy with a slow ass fwd Honda that means a lot. I have a fwd, should stop racing it?

To the OP, you should get some nice tires instead of the LSD. I have Hoosier QTPs which are 26x9.5x16 and an open diff and cut consistent 1.80s and some 1.7s. Although not great 60' times, they are good enough to make clean passes and not break stuff. I'm still using the stock tranny and axles. The best part about these tires is they hook on the street too.

Wow, I figured with that level of power an LSD would be a must. Good to know the factory parts are withstanding those killer times.

I wrote down the tire you're running so I'll see about going that route. Did you use the stocker 16'' wheels? Or did you have to go with something wider?

Edit - I see you are running the stock 2g wheels. Good to know.

 

[945liter]

Coming from a guy with a slow ass fwd Honda that means a lot. I have a fwd, should stop racing it?

To the OP, you should get some nice tires instead of the LSD. I have Hoosier QTPs which are 26x9.5x16 and an open diff and cut consistent 1.80s and some 1.7s. Although not great 60' times, they are good enough to make clean passes and not break stuff. I'm still using the stock tranny and axles. The best part about these tires is they hook on the street too.

THE CONSULTANT HAS SPOKEN

 

[16vdohcturboawd]

I would go with the quaife and some 17" drag radials myself. Im hoping for low 8s or high 7s in the 1/8th this summer with my fwd. It only managed a 9.0 last year at 15psi on the evo 3 but that was before the fp2s. I plan on getting meth injection soon and hopefully a quaife. I think Im just going to stick to the stickiest street tires I can find though, im lazy.

 

[richard33]

17" drag radials will not work. You need a tire with some sidewall.

 

[daren_p]

First off, don't be dissapointed if you don't see 11's this year, its defently not an easy task in a fwd, especially if your new to driving at the track, which alot of the time, makes the biggest difference, especially in a fwd car. I converted my car to awd so have experience with fwd & the track. The Quaife will make a huge difference in putting the power down on the street in both the straight & corners & is defently worth the investment. But even with the Quaife, at the track with a lower profile set of tires, your going to have a hard time hooking up, even with good track prep. With my 225/40/18 street tires I never managed better then mid 13's & I was right around the 410-430whp level. Even with proper track prep, the car whould break lose & hop in both 1st & 2nd. Now that the cars awd & I have experience launching the car, I think I could probably have got a better launch when it was fwd but I believe my best 60ft was about 2.2.

I then switched to Hooser DR's & dropped to the mid 12's & there was still more left in the setup. DR's or slicks will defently make a much bigger difference in your times vs a Quaife but you always run the risk of exploding the stock open diff (weak link) with some wheel hop. Slicks are less likely to hop & with their softer sidewall, they have more "give" on the launch. Biggest rim diameter they make in a bias ply would be 16" (hoosier QTP's), for a true "slick" you need to go down to a 15" rim. For DR's Hoosier makes a 225/50/16 (what I had, with my Wilwood brake kit), that offer the softest sidewall. BFG is the only company that makes a 17" DR that will work for us. I don't have experience with the BFG's but I know members on here run them & have seen a bunch of SRT4 guys run them at the track with good results. Sure, they won't be as good as a 15" slick but they will be a tonn better then street rubber.

Also, my tires at that time were Kumho MX's so it wasn't like I was running a junk all season.

 

[richard33]

First off, don't be dissapointed if you don't see 11's this year, its defently not an easy task in a fwd, especially if your new to driving at the track, which alot of the time, makes the biggest difference, especially in a fwd car. I converted my car to awd so have experience with fwd & the track. The Quaife will make a huge difference in putting the power down on the street in both the straight & corners & is defently worth the investment. But even with the Quaife, at the track with a lower profile set of tires, your going to have a hard time hooking up, even with good track prep. With my 225/40/18 street tires I never managed better then mid 13's & I was right around the 410-430whp level. Even with proper track prep, the car whould break lose & hop in both 1st & 2nd. Now that the cars awd & I have experience launching the car, I think I could probably have got a better launch when it was fwd but I believe my best 60ft was about 2.2.

I then switched to Hooser DR's & dropped to the mid 12's & there was still more left in the setup. DR's or slicks will defently make a much bigger difference in your times vs a Quaife but you always run the risk of exploding the stock open diff (weak link) with some wheel hop. Slicks are less likely to hop & with their softer sidewall, they have more "give" on the launch. Biggest rim diameter they make in a bias ply would be 16" (hoosier QTP's), for a true "slick" you need to go down to a 15" rim. For DR's Hoosier makes a 225/50/16 (what I had, with my Wilwood brake kit), that offer the softest sidewall. BFG is the only company that makes a 17" DR that will work for us. I don't have experience with the BFG's but I know members on here run them & have seen a bunch of SRT4 guys run them at the track with good results. Sure, they won't be as good as a 15" slick but they will be a tonn better then street rubber.

Also, my tires at that time were Kumho MX's so it wasn't like I was running a junk all season.

good info here.

So with good track prep and good street tires he was cutting 2.2 60fts with the LSD.

With the open diff and my QTPs I was cutting 1.7-1.8s on over 20 passes with 2nd gear burnouts with no problems.

No offense to you Daren just trying to help this guy with some #s from either setup.

You will regret going with a 17in drag radial trust me. A 15 or 16" slick will completely change your car for the better.

 

[dsmrollerz90]

Not to be rude, but..... Why in the hell is there an Integra on a DSM forum!?!?!?

Obviously he does not know what kind of power we put down with E85. I have more mods than the OP, but im on regular 91oct. and I hope I am running 400hp. Once I go to E85, I'll be coming close to 500hp!!

 

[daren_p]

good info here.

So with good track prep and good street tires he was cutting 2.2 60fts with the LSD.

With the open diff and my QTPs I was cutting 1.7-1.8s on over 20 passes with 2nd gear burnouts with no problems.

No offense to you Daren just trying to help this guy with some #s from either setup.

You will regret going with a 17in drag radial trust me. A 15 or 16" slick will completely change your car for the better.

No offense taken, thats exactly the info the OP needs. I went from about a best of 2.2 with street tires to 2.0 flat with the DR's. I didn't have very many passes on them (less then 10) & one outing was at the end of the season with poor track prep but I'm sure 1.9's could be had, no problem on those DR's & 1.8's probably wouldn't have been out of the question either.

As mentioned, I don't think I had the best technique down for launching the fwd, as with never experiencing proper traction off the line I didn't really know what to try & achieve. I believe I was getting more bog & then spin compared to an ideal fwd launch. With better technique I believe I could now drop those street tire 60's but I think a 2.0 would be about the best that could be done, if everything was "just right". 2.1's are probably more doable.

 

[1TireFireTSi]

good info here.

So with good track prep and good street tires he was cutting 2.2 60fts with the LSD.

With the open diff and my QTPs I was cutting 1.7-1.8s on over 20 passes with 2nd gear burnouts with no problems.

No offense to you Daren just trying to help this guy with some #s from either setup.

You will regret going with a 17in drag radial trust me. A 15 or 16" slick will completely change your car for the better.

I've decided for this season to pick up a set of 26'' drag slicks and some 15'' wheels, dial in my suspension, and learn to do some racing. High 11s are my goal but I would be surprised if I even hit 12s on my first few passes. I've got to set up my 2 step, boost by gear, and learn to launch the car on slicks. I'm thinking if I go with the 26'' slick, it'll be plenty of tire and I might get away with not even having to warm them up prelaunch. It'll all be a learning experience though.

Down the road, perhaps if I break the differential, a Quaife will find it's way in eventually. I like the idea of a car you can enjoy on the street as well as the track and the LSD is a must for mine.

 

[richard33]

nice. Good decision but you'll probably need to warm them up so they are extra sticky

 

[daren_p]

Down the road, perhaps if I break the differential, a Quaife will find it's way in eventually. I like the idea of a car you can enjoy on the street as well as the track and the LSD is a must for mine.

Just a heads up if you don't already know, if the stock open diff happens to explode it typically makes an "inspection hole" in your tranny

 

[1TireFireTSi]

Just a heads up if you don't already know, if the stock open diff happens to explode it typically makes an "inspection hole" in your tranny

Haha. I'll have to be careful that's for sure.