club-racers and motorheads

Lowell_M

I've been trolling along at the G35 forum asking some questions and 99% of the people on there are teenagers more interested in having a loud exhaust than actually knowing how to drive a car at it's limits and adding performance capability to their cars... So, I know we have some motorheads here....

A guy worked with a speedshop to add twin turbos to his 2007 G35 Sedan, raising horsepower from 306 at the flywheel stock to 460 at the rear wheels boosted. My question to him was drivability at that much of a power increase. I can understand adding that much horsepower to a Vette or a Viper because there is a large contact patch for the rear tires to grab with since they are 300mm+ wide. The G35S comes with 245mm rear tires and I'm not sure there's room for anything wider. The tires are the stickiest street tires that Bridgestone manufactures.

Does anybody here have any experience adding FI to a RWD car with similar limitations in grip and have any comment on the ability of the car to get the power to the ground? I'm not interested in a drag strip setup, rather a roadcourse setup.

daboyz

Forget this and just send me the cash for all the tickets you'll get.:D

Joe08867

It is a matter of balance. The horsepower is only part of the equation. I always try to set the car up handling and braking wise before the extra ponies.

It is easy to get in over your head with the loud pedal when the car isn't equipped to handle the power.

That said the horsepower increase you speak of isn't to extreme. It can make a good car great and really help in the handling department. It gives you room to correct with the engine more so than the original car could ever do.

It also depends on where the power is in the revband. Tons of low end will break the tires loose in a millisecond and all of it up top can make it a bit of a handful in the turns if you aren't accustomed to it.

The first I would do is drop the center of gravity and stiffening the front end and mildly mellow the rear. You want it to follow you more than lead you.

heiney9

a_mattison wrote: »

I've been trolling along at the G35 forum asking some questions and 99% of the people on there are teenagers more interested in having a loud exhaust than actually knowing how to drive a car at it's limits and adding performance capability to their cars... So, I know we have some motorheads here....

A guy worked with a speedshop to add twin turbos to his 2007 G35 Sedan, raising horsepower from 306 at the flywheel stock to 460 at the rear wheels boosted. My question to him was drivability at that much of a power increase. I can understand adding that much horsepower to a Vette or a Viper because there is a large contact patch for the rear tires to grab with since they are 300mm+ wide. The G35S comes with 245mm rear tires and I'm not sure there's room for anything wider. The tires are the stickiest street tires that Bridgestone manufactures.

Does anybody here have any experience adding FI to a RWD car with similar limitations in grip and have any comment on the ability of the car to get the power to the ground? I'm not interested in a drag strip setup, rather a roadcourse setup.

Aaron I know what your concerns are. You need to find a forum or other source of information for you particular car because obviously there are good tweaks and bad tweaks. Twin turbo's by their nature are problematic especially in the aftermarket. My brother had an Audi S4 with the V6 Twin Turbo's. His was brand new and he really had no issues the first 2 years, he sold it before the warranty ran out. But many owners as the car got older had some issues.

First question I would ask is why a twin? Can't pretty big gains be made from a single turbo? All I can say being a part of the VW tuning scene for 20 years is to do all the research you can for your specific car and application to get a feel if the particular work you want to do will be what you want.

Unfortuneatly these kinds of things can't be test driven and when you are spending thousands of dollars for upgrades, etc. you need to make reasonably sure things are going to work for you application. If you had a VW I could give you loads of info as well as a few race car drivers to give you some advice. No one up at Blackhawk can give you some advice?

H9

Joe08867

heiney9 wrote: »

First question I would ask is why a twin? Can't pretty big gains be made from a single turbo? All I can say being a part of the VW tuning scene for 20 years is to do all the research you can for your specific car and application to get a feel if the particular work you want to do will be what you want.

Unfortuneatly these kinds of things can't be test driven and when you are spending thousands of dollars for upgrades, etc. you need to make reasonably sure things are going to work for you application. If you had a VW I could give you loads of info as well as a few race car drivers to give you some advice. No one up at Blackhawk can give you some advice?

H9

Good point H9 about the twin turbos. Unless they were looking to spool them up quicker. Two small turbos can get things in motion quicker than one. But the added piping and tuning issues can become a bear.

H9, my brother in-law is a VW tuner. Mostly older water cooled stuff. His shop Oldskool Industries is on VW Vortex. You guys should talk.

heiney9

Joe08867 wrote: »

H9, my brother in-law is a VW tuner. Mostly older water cooled stuff. His shop Oldskool Industries is on VW Vortex. You guys should talk.

I'm on the Vortex quite a bit; but I find the same as Aaron, there are mostly 19-25 year old kids trying to lower their 1/4 mile times and they either don't have knowledge/expertise and money to do things the proper way. I wade through that crap and do get some good info. SOme of the "younger guys" stories are quite amusing

I've read several amusing articles over the years about cars with a 50hp disadvantage but a proper suspension set-up that just eat the higher hp cars around the track.

You are correct it's all about balance and the first thing I do to any of my Volks is get rid of the crappy North American suspension that comes stock then I try to make affordable power. I have a VR6 GTi and the words affordable and power don't got together-LOL

So a_mattison if you haven't tweaked the suspension I'd start there. Can't remember what we discussed. Summer is almost over and I can't believe I haven't been up to Blackhawk yet with you just to observe.

H9

concealer404

You can fit wider than 245 back there. And really, for 400whp in a car that heavy, traction will be easily controllable. Now, i'm not saying it'll dead hook coming out of really tight corners mashing the gas, but few properly powered cars will handle that anyways.

There's a G35 coupe locally here that has two GT30R turbos on it making about 550, and yeah, he's got wheelspin in 1st and 2nd, but it's easily controllable.

I don't know what suspension work you have, but whoever suggested doing that first is on the right track. Nothing is worse than having a very powerful car with an unsorted suspension. (Take it from the guy that put a stock-suspensioned CRX in the 11s. Was NOT fun to drive.)

Lowell_M

Thanks for the thoughts guys! Yea... I'm thinking all around tuning and not just HP. My first step will probably be the brakes. I have the sport model which comes with bigger brakes (13" rotors) but still single piston calipers. I know I could do a little better with stainless lines and some 4 or 6 piston calipers. I know I could go a little deeper into turns, but am always afraid of fade. Nobody makes street/track pads for my car yet, but Hawk has the HP+ pads coming for it in a few months. EBC is right behind them with their yellow stuff.

The suspension on this "sedan" is unbelieveable for stock, in my opinion. take a look at the picture I posted at the top. That is me at about 80mph coming through the carosel hard at Blackhawk Farms Raceway. Look at the comparative body roll of the STI in the same turn. The G35 sport is very tightly sprung and stays pretty flat for a street "sedan"

The FI plan is a little down the road. The shop in CA used twin turbos to ease spool up. One big problem with boosted cars on a roadcourse is oversteer caused by boost coming on too fast. I know some guys at blackhawk have up'd their boost pressure on the sti's and they become nearly uncontrollable out of a turn because you have to anticipate the turbos.

I've had cars in my blood forever, taken the skip barber course, done parking lot autocross etc. but this year is my first on track, high speed, time trialing experience. It is an absolute blast. Parts (and mistakes on track) are expensive for this G35 and, frankly, the limits of the car might be a little high for my abilities right now, so I am considering putting together an early 90's Honda Prelude or something similar for track days. I'm still considering the FI for my G35 just for kicks...cause you never have enough power. Seriously, though, Infiniti has done a sweet job with the G35... It is a "family sedan" with 300 hp and drives like a 350Z on the track.

Lowell_M

heiney9 wrote: »

So a_mattison if you haven't tweaked the suspension I'd start there. Can't remember what we discussed. Summer is almost over and I can't believe I haven't been up to Blackhawk yet with you just to observe.

H9

I know! There is only one more track day that I can get to and its at the Autoban in Joliet. You're welcome to check it out if you want. That is a sweet track down there.

I've done pretty well at Blackhawk for my first time around. My times are....average, which I really couldn't expect much better. HSAX is like golf... You could be having the round of your life and screw up one hole that ruins the round. There are 7 turns at blackhawk... I've had a couple laps that felt perfect until turn 7 and I turn in too soon and miss the apex, so I'm 20 mph slower coming out of the turn...there goes my time.... It sure is fun though.

heiney9

I'm certainly not here to lecture and I know you've done your homework. Be careful with track braking set-ups. Many times the pads you choose for the track suck (read dangerous) for the street. Hawk makes some very nice x-over pads. Just don;t go all out if you plan on using your car for the street. SS lines, really good Brake fluid and the correct pad go a very long way. Upgraded calipers are nice but they get pricey very quick and unless it's a balls to the wall race car they rarely give more than an incremental increase in braking ability.

Slotted, drilled rotors really help but they get eaten up very quickly at the track so be prepared to change those out more than solid or vented rotors.

Right now for the type of autocross you do the correct pad and nice slotted/drilled rotor, SS lines and a proper racing brake fluid should get you much better braking ability. I'd put money into suspension tweaks (even though you feel stock is adequate) before I'd spend upwards of $1K on new multi piston calipers. But that's just my advice based on where you are at right now.

H9

concealer404

heiney9 wrote: »

I'm certainly not here to lecture and I know you've done your homework. Be careful with track braking set-ups. Many times the pads you choose for the track suck (read dangerous) for the street. Hawk makes some very nice x-over pads. Just don;t go all out if you plan on using your car for the street. SS lines, really good Brake fluid and the correct pad go a very long way. Upgraded calipers are nice but they get pricey very quick and unless it's a balls to the wall race car they rarely give more than an incremental increase in braking ability.

Slotted, drilled rotors really help but they get eaten up very quickly at the track so be prepared to change those out more than solid or vented rotors.

Right now for the type of autocross you do the correct pad and nice slotted/drilled rotor, SS lines and a proper racing brake fluid should get you much better braking ability. I'd put money into suspension tweaks (even though you feel stock is adequate) before I'd spend upwards of $1K on new multi piston calipers. But that's just my advice based on where you are at right now.

H9

Actual drilled rotors are dangerous.

If they have holes cast into them, that's another matter.

heiney9

concealer404 wrote: »

Actual drilled rotors are dangerous.

If they have holes cast into them, that's another matter.

I assumed everyone knew I meant cast.....but thanks for clarifying

concealer404

heiney9 wrote: »

I assumed everyone knew I meant cast.....but thanks for clarifying

Haha, i figured that's what you meant.... just didn't want anyone going out and grabbing those awesome ebay ricer specials.

Moot point for me, because i can't get slotted rotors for my car anyways, and i kindof need them. I think i've done pretty much everything i can to combat fade, and it still gets a little sketchy after a Dragon Run or two. Which, i do realize that that's a bit more extreme than a road course or autocross, but it still bugs me.

I've been bugging PowerSlot for months about it, to no avail.

Lowell_M

heiney9 wrote: »

I'm certainly not here to lecture and I know you've done your homework. Be careful with track braking set-ups. Many times the pads you choose for the track suck (read dangerous) for the street. Hawk makes some very nice x-over pads. Just don;t go all out if you plan on using your car for the street. SS lines, really good Brake fluid and the correct pad go a very long way. Upgraded calipers are nice but they get pricey very quick and unless it's a balls to the wall race car they rarely give more than an incremental increase in braking ability.

Slotted, drilled rotors really help but they get eaten up very quickly at the track so be prepared to change those out more than solid or vented rotors.

Right now for the type of autocross you do the correct pad and nice slotted/drilled rotor, SS lines and a proper racing brake fluid should get you much better braking ability. I'd put money into suspension tweaks (even though you feel stock is adequate) before I'd spend upwards of $1K on new multi piston calipers. But that's just my advice based on where you are at right now.

H9

Thanks. I'll see what pads and lines (as well as frequent fluid flushing) do for me. The Hawk HP+ pads are the crossover pad that you speak of. They have cold bite, but still have high friction at elevated temperatures. It is the compound that most guys at BHF use on daily driver/track cars. The EPS Yellow Stuff pads are similar.

Lowell_M

concealer404 wrote: »

Haha, i figured that's what you meant.... just didn't want anyone going out and grabbing those awesome ebay ricer specials.

Moot point for me, because i can't get slotted rotors for my car anyways, and i kindof need them. I think i've done pretty much everything i can to combat fade, and it still gets a little sketchy after a Dragon Run or two. Which, i do realize that that's a bit more extreme than a road course or autocross, but it still bugs me.

I've been bugging PowerSlot for months about it, to no avail.

I"ll probably go slotted from Stoptech.

concealer404

a_mattison wrote: »

Thanks. I'll see what pads and lines (as well as frequent fluid flushing) do for me. The Hawk HP+ pads are the crossover pad that you speak of. They have cold bite, but still have high friction at elevated temperatures. It is the compound that most guys at BHF use on daily driver/track cars. The EPS Yellow Stuff pads are similar.

Yeah, i run SS lines, stock calipers, stock rotors, EBC Yellow Stuffs, and DOT 5 fluid. It's a good setup. Little weird the first couple stops of the day, have to stand on the pedal pretty good, but after that, really easy to drive on the street.

Lowell_M

heiney9 wrote: »

I'm certainly not here to lecture and I know you've done your homework. Be careful with track braking set-ups. Many times the pads you choose for the track suck (read dangerous) for the street. Hawk makes some very nice x-over pads. Just don;t go all out if you plan on using your car for the street. SS lines, really good Brake fluid and the correct pad go a very long way. Upgraded calipers are nice but they get pricey very quick and unless it's a balls to the wall race car they rarely give more than an incremental increase in braking ability.

Slotted, drilled rotors really help but they get eaten up very quickly at the track so be prepared to change those out more than solid or vented rotors.

Right now for the type of autocross you do the correct pad and nice slotted/drilled rotor, SS lines and a proper racing brake fluid should get you much better braking ability. I'd put money into suspension tweaks (even though you feel stock is adequate) before I'd spend upwards of $1K on new multi piston calipers. But that's just my advice based on where you are at right now.

H9

Actually, now that I think about it... for the HSAX full racing pads are kinda dangerous anyway. For the timed runs you start half way down the front sraight from a standstill and everything is cool (tires and brakes) I've seen guys with racing pads go off track in turn one because they hit the braking zone at 90 mph and try to go deep into the turn with their fancy brakes, but they aren't hot enough to have any bite yet.

heiney9

Tire pressure is EXTREMELY important and I know most of the VW guys use nitrogen in their race tires. It's not a bad tweak for the cost if you race. My suspension is pretty tight (aftermarket Bilsteins w/ H & R) and I can notice a 2-3psi difference on the street. It's really weird, because I can tell immediately that one or more tire pressure is off by how the car behaves, but visually it looks fine.

The way the tire pressure changes thorughout the season drives me nuts. I'm constantly adjusting as the weather changes.

H9

Face

Two words, PEDAL MODULATION.

Lowell_M

heiney9 wrote: »

Tire pressure is EXTREMELY important and I know most of the VW guys use nitrogen in their race tires. It's not a bad tweak for the cost if you race. My suspension is pretty tight (aftermarket Bilsteins w/ H & R) and I can notice a 2-3psi difference on the street. It's really weird, because I can tell immediately that one or more tire pressure is off by how the car behaves, but visually it looks fine.

The way the tire pressure changes thorughout the season drives me nuts. I'm constantly adjusting as the weather changes.

H9

No kidding! I discovered the importance of controlling hot air pressure at the last track day. 2 psi in the front made the difference between nuetral handling and extreme oversteer. and you have to tune the pressures hot. I don't mess with Nitrogen because you have to bring the pressure up a few psi when you get to the track and then adjust from there after your first lapping session when you get the feel for the track that day and get the tires heated up.

It really is a fun hobby and I've learned a ton about driving and the importance of the car setup this summer.

Lowell_M

Face wrote: »

Two words, PEDAL MODULATION.

That's all I needed? Sign me up for an F1 team then, I'm good to go.

Lowell_M

http://www.6mt.net/forum/g35-sedan/28203-vq35hr-tt-project-near-completion.html

Here's a link to the guys post about the TT install if you are interested in the pictures and dynographs.

H9, What are you thinking would be a logical first tweak to the suspension? Maybe stabilizer bar upgrades to stiffen things up a little bit? I think I've got a little room to drop it to lower the cg a bit, but not sure I want to go there.

dkg999

Not sure what the issue with drilled rotors is on cars. For years with sport/race bikes I used a milling machine to drill and slot brake rotors on bikes the regularly went over 200 mph. Never had a problem and it was standard practice on those bikes by everyone. The trick was to use lots of coolant to keep the rotors cool while you milled them, then to turn them flat after they had cooled. Did they discover something unsafe about this?

I was actually contemplating pulling the rotors off of my 2004 Chevy Silverado Labor Day weekend and drilling and slotting the rotors and putting on ceramic brake pads. It would be nice to have a little more braking power when I'm pulling heavy loads. Of course I haven't used the milling machine in the shop for about 10 years or more, so I might have to bribe someone to help me

Face

You don't want drilled rotors or ceramic pads if you drive hard.

I've cracked drilled rotors, and so have a few of my friends.

Ceramic pads will chunk if heated up. Large clumps of brake pad material isn't fun to remove off pretty wheels.

Carbon metallic pads handle heat much better, last much longer, and won't warp your rotors as quickly.

dkg999

Now just how hard do you think I'm going to drive a full sized Chevy truck? It's not like I'm planning on embarrasing a_mattison on the track! Of course I'll need enough brakes to haul his car home on a trailer once he breaks it :eek:

Seriously, many of the heavy haulers recommend ceramic brake pads when pulling heavy loads. I'll take a look at the other options.

Lowell_M

dkg999 wrote: »

Now just how hard do you think I'm going to drive a full sized Chevy truck? It's not like I'm planning on embarrasing a_mattison on the track! Of course I'll need enough brakes to haul his car home on a trailer once he breaks it :eek:

Seriously, many of the heavy haulers recommend ceramic brake pads when pulling heavy loads. I'll take a look at the other options.

Face's comment is a little too broad sweeping. Check out Hawk brakes webpage. I think they have some pads designed for your application. There are many different brake compounds.

The issue with drilled rotors is stress-risers. When the rotor heats up, it expands and this coupled with localized heating at the edge of the drilled holes can cause microcracks that turn into bigger cracks. Most use slotted rotors rather than drilled for this reason.

Lowell_M

Face wrote: »

You don't want drilled rotors or ceramic pads if you drive hard.

I've cracked drilled rotors, and so have a few of my friends.

Ceramic pads will chunk if heated up. Large clumps of brake pad material isn't fun to remove off pretty wheels.

Carbon metallic pads handle heat much better, last much longer, and won't warp your rotors as quickly.

Also, rotors generally don't warp. The pulsating you feel 99% of the time is uneven brake pad material transfer to the rotors.

heiney9

a_mattison wrote: »

Also, rotors generally don't warp. The pulsating you feel 99% of the time is uneven brake pad material transfer to the rotors.

LOL- you mean quality rotors don't warp. Anything you buy at Pep Boys; Advanced Auto; Auto Zone, etc. is crap.............well for the most part, especially if you are looking beyond mediocre performance. You get what you pay for and cheap Chinese rotors are CRAP. I fortunately don't know from experience but my mechanic has buckets full of 20K mileage rotors from places like this and they look like crap. At $29 a rotor or whatever ridiculous low price; you get what you pay for.

Sorry for the off topic rant. If you are autocrossing or have a performance car stay away from discount auto retailers.

H9

Lowell_M

heiney9 wrote: »

LOL- you mean quality rotors don't warp. Anything you buy at Pep Boys; Advanced Auto; Auto Zone, etc. is crap.............well for the most part, especially if you are looking beyond mediocre performance. You get what you pay for and cheap Chinese rotors are CRAP. I fortunately don't know from experience but my mechanic has buckets full of 20K mileage rotors from places like this and they look like crap. At $29 a rotor or whatever ridiculous low price; you get what you pay for.

Sorry for the off topic rant. If you are autocrossing or have a performance car stay away from discount auto retailers.

H9

Well...yea. I guess I don't even think in that direction. In all reality, though, what most people think is rotor warpage causing pulsation is actually pad transfer. When you bed a new set of pads into a rotor you are actually depositing pad compount into the rotor material. If your rotors get really hot and you are sitting at a stop light with the brakes on, a lot of material transfers causing a high spot on the rotor. A dead giveaway of this happening is a distinct outline of the pad on the rotor surface. See it all the time. the guys at stoptech have an article that speaks to this technically and quite clearly. I'll see if I can find it.

Lowell_M

http://www.stoptech.com/tech_info/wp_warped_brakedisk.shtml

Well... That was easy to find.

Lowell_M

Thanks for the conversation on these topics, by the way. I've been trying to talk about this stuff with the peeps on the G35 forum and all anybody wants to talk about is weather or not they can beat a Mustang out of the light or other worthless crap. who'd a thought I'd have to have this conversation in an audio forum.