driftxsequence

iTrader: (8)

I picked up a set of MINT housings and was informed that the oil injector holes were blocked off(JB weld). As such, with road racing there is a good amount of time where you are in gear and slowing down off throttle. Knowing that premix is only injected when fuel is injected, is this something I need to be worried about? I understand this is not as big of a concern for those who DD but what about doing this at 7000-8000 RPMs for 20 minutes at a time...?

I do have a Megasquirt, so I assume I could turn off decel fuel cut during the sessions, but I'm not sure what kind of repercussions that would have. any other options? Maybe I'm not searching the right keywords..


Instead of making two threads, I have a second question. Considering the car is being built with track time in mind, what mods are necessary for said track car? I guess I should include the mods and my goals. I am trying to build an engine that will realistically last 3-5 years. 350-400WHP (400 at the most). The car is not a DD. It will see 3-6 sessions a year and the occasional weekend / car meet. I would like the car to still be road legal! I am still gathering parts at the moment for the rebuild, so if you see anything you think see that should be changed please voice your opinion!

Car is a S4 base with 5 lug swap - 4 pistons in the front with slotted/drilled rotors in front, solid vented disks in the rear.
Building a vmount with evo 8 intercooler, koyo radiator
NA drivetrain - is it sufficient since the car isnt being launched? Do I need a limited slip diff?
AC removed

As for the engine
Megasquirt ECU (have)
4 x 1000cc ID injectors
S4 turbo rotor housings and irons (have)
S6 rotors (got a good deal on them) (have)
S4 hybrid turbo (have)
Turblown engine stud kit (have)
stock oil cooler (have)
Clutchmasters stage 3 NA clutch (have)
FD auto counterweight + lightweight NA flywheel(good idea?)
Auxiliary injection (havent decided on a kit yet)
apex seals? I assume I want a softer set of seals since I will see high RPM for extended periods of time?

CrispyRX7

iTrader: (139)

I'll answer the first question only...the second will illiciate many responses that will likely be all over the map. The answer to your question is simple: add premix to your fuel and the entire MOP system is not needed. It's also more reliable. Good luck at the track!

Regards,
Crispy

MrGoodnight

iTrader: (1)

He's asking about when your up in the higher rpms decelerating before a corner, since there is no fuel being injected, there will be no premix injected to lubricate the housings and seals.

I'm curious about this as well..

eage8

iTrader: (9)

question 1: you slow down a lot faster than you accelerate, there isn't a lot of time when you're off throttle. on the street your off throttle far more often. no one has ever had an issue road racing pre-mixed cars.

question 2: concentrate on cooling and brakes. power can wait (unless your engine is currently blown)

for that kind of power levels you'll need a nice radiator, front brake ducts, track brake pads (Hawk DTC60s?), possibly dual stock oil coolers...

heat shield anything you can near the exhaust.

you'll definitely need an LSD. aaroncake experimented with ~400 whp and a NA drivetrain, last I checked he blew up his transmission on the street.

what track do plan on going to? NJMP? Summit point?

tracking a car is a lot easier with less horsepower

BLUE TII

iTrader: (9)

Yes, simply turn the fuel cut on decel off as you say and premix. Its actually easier to tune with fuel on decel as it won't buck going from super rich on gas to lean off gas.

Side effect is its more likely you will shoot flames/smoke on decel.

The second part of your question. My car is a 2,500lb S4 TII converted to NA base interior/exterior, horizontal mount IC, 380rwhp @14psi S5 stock hybrid with 60mm external wastegate.

If you plan to track the car use a divided manifold/turbo with a T4 exhaust side even though you "only" want a reliable 350-400rwhp. Reason is the small stock hotside is such a restriction all the exhaust heat gets trapped in the engine and you cook your coolant seals and the rotor seals.

Run it on race gas even though you are only at "pump gas boost levels" if you want it to last on the track.

The NA transmission is not strong enough, but you can replace it once you find out by breaking it.

You do need a limited slip, but you can put one in with the TII drivetrain swap once you drive it and figure out how much you want a limited slip.

Davidss

Are you willing to turn the boost down on track?

driftxsequence

iTrader: (8)

Thank you for the replies! let me try and answer everyone

eage8: Mostly NJMP, my friend would like us to hit up VIR eventually as well (he thinks his cobalt ss/tc will beat me....hahahaha)

I will definitely look into heatshielding the exhaust, I have a koyo aluminum rad and have a buddy who works with aluminum that will be able to help me build some really good duct work. Yes the engine is currently blown so I am in the process of building it up and acquiring parts. I cracked the rear iron on a S4 NA 6 port turbo build.

I am willing to play with the NA drivetrain for a while, and I would be okay building a car with less power as long as it is reliable.

BlueTII: at what level do you think the aftermarket exhaust manifold is necessary? I'd like to be able to get away using the stock one until I go with an aftermarket turbo.

I will do some reading on the race gas, I havent read up on it much at all.

Davidss I am willing to turn down the power for reliability yes. As said before, my goal is a reliable 350-400 whp, so if my funds dont allow that, I am willing to sacrifice power, for reliability. If it takes another two years to get to that level I'm okay with that. Hell, even running stock boost will make more power than a streetport NA!

eage8

iTrader: (9)

I would start the car off at stock boost. I'm currently turning my rx7 which was/is and autocross car into a track ready car (and semi-retiring my corolla from track duty) and it's taken quite a lot of work...

I plan on starting my car off at stock boost (around 250whp when I was tuning it before I turned my boost controller on) just to make sure the cooling system can take it. I'll probably have a lower boost level for track and a higher level for auto-x.

nothing is worse than having to come in early because your car is overheating or your brakes are gone... (well, besides crashing...)

a rollbar, 6 pt. harnesses, and decent racing seats might also be a good idea eventually, but aren't necessary...

race fuel is probably a bit extreme... dual oil coolers, and an aftermarket intercooler and radiator and lots of ducting will help with the heat.
Here is a write up on dual stock oil coolers:
Triple-R: FC3S Buildup - Chapter 3: Part 28

it's actually crispyrx7's site, there is a lot of good info on there.

driftxsequence

iTrader: (8)

Just read that whole thing from start to finish. I wish I had the time and money to do that! I am gonna start out with just a single oil cooler with good duct work.

My plan was to take the oil cooler and do a 180 with it so that it mounts forward 3-5 inches so I can fit the radiator down a bit more (vmount set up) I was going to get AN lines and a nice big 180* fitting for the front cover. Is that safe to do? Figured it would be easier to mount that way than having to get new lines anyway, and then figure out some way how to mount the oil cooler.