DaveK

iTrader: (21)

IMO, you'd be able to drive through deeper snow. One of the reasons this type of setup is so popular on the Euro Rallycross cars is that even if you have cars in front of you kicking up mud, your radiator can't get caked with mud and block all the airflow.

I seem to remember a few years ago a WRC car overheated an engine when they partially nosed into a snow bank. The bumper opening packed with snow and blocked all airflow from the radiator.

IMO, the downsides are as follows:

1) more line length and fittings
2) electric water pump could fail
3) system is driven by working fans, so if the fans break...
4) additional system weight

Dave

KevinD

iTrader: (56)

5) extremely critical to get air flow through radiator correct or you'll be overheating all the time.

our formula SAE car had radiators in the sidepods. it worked excellent until we would put the front wings on. with the wings on no air flow was moving through the sidepod and it was constantly overheating. this was even with double the radiator size, and a puller fan with a full shroud. so my experience using a fan only to cool your car isn't going to cut it. you need to be sure air is moving over it in addition to what the fan can move.

DaveK

iTrader: (21)

Thanks for bringing another perspective! I'm wondering if in your situation the vacuum you were creating with the wing wasn't also causing the fans have problems sucking air in? Sort of like trying to make too much boost on a rally car with a restrictor...at some point you just end up cavitating the air (not sure if that's the proper word), heating things way up, and you don't make any additional boost.

Dave

DaveK

iTrader: (21)

Hey guys, had a question related to the rear mounted radiator. I've been thinking this stuff over in my head over the last couple weeks and was wondering if anyone might be able to help me with this:

How much heat do you think the OEM oil cooler sheds vs. coolant?

Here's why I'm asking. On my Evo, I replaced the OEM oil cooler with a Mocal oil/water unit. The primary reason for my move was to add "rally durability"...i.e. get the low hanging parts that could cripple a car in a minor wreck/jump/rock hit away from the ground. The problem with this move is that it added to the amount of cooling that the coolant needed to do since there's no longer an oil/air cooling.

So, what I'm thinking is that if I move the radiator to the trunk, I've now got a great place to put the oil cooler, right above the IC where it will get clean airflow through the upper part of the grill, and its nowhere near the ground.

The question now becomes, what's the optimal oil temperature...or how cool can I make the oil before it's too cool? I figure I can have some block off plates available to decrease the efficiency of the oil cooler if I'm running in cooler weather, or a thermostat might work too.

Thanks!

Dave

houdini_678

Euro Rally Cross (Slash) America Rally looks great... didn't even know such excisted; phenomenal.

Thanks DaveK

Oh... and pertaining to a rear mounted radiator, James Cameron said it best: Failure IS an option, Fear is not.

JohnBradley

iTrader: (30)

UR quattro, Drift cars, Mud wheelers, rear mounted is actually pretty popular. You can run the coolant lines through the unibody channel for some added protection.

Look at the Team Orange drift STi specifically for how they set it up, I think the Evo might be similar though.

aaron

donour

iTrader: (6)

That's a good question in general. The number that I have seen thrown around is 190 F, which I figure is below what you can realistically get from a loaded engine.

I've never seen anybody try to get the engine oil as cool as possible. 190 comes from a study on engine wear during warmup. The 185-190 F range was where lubrication efficiency flattened out. By dropping down to ~150 F, wear increased something like 250%. I wish I had the reference handy to point to...

d

Evo-Dan

bad idea

DaveK

iTrader: (21)

Which, rear mounted radiator, or the oversized oil cooler? In either case, any additional information you can share to highlight why it might not be a good idea or what the typical pitfalls are would be much appreciated.

Dave

fbikawi

iTrader: (1)

this rally cross evo has the radiator mounted at the back.
i was looking into this for my hill climb car and the main reason was weight distribution.
also another intresting project. Evo X with Evo 9 engine!

http://www.stevehillmotorsport.com/

DaveK

iTrader: (21)

Alright guys, I've been mulling this rear radiator thing over in my head for the last couple weeks. After a marathon session of looking at Euro RallCross cars for inspriation, I think I'm going to make the jump.

Hard to argue with making room in the engine bay (see first attached pic), and the other thing I'm noticing is that not all cars are using ducting in the rear quarter panels, which leads me to believe that its the ducting after the radiator (and a leaky interior) that's most important.

Since I've already got a thread going about my 2010 re-prep, I will post updates there.

Dave

H-TUNER

Hey Dave! You building this car for competition? Or for the street? I would only recommend this level of modification for a competition car. you will lose most, if not, all of your trunk for storage. I know the Crawford/Verdier car quite well. I was part of the Formula-D technical scrutineering team for the past couple of years and have spent alot of time around, and inspecting that particular vehicle. I can't imagine cutting any car up to that degree for the street. It's just not worth the work and expense. Competition has its own requirements however. Definitely should think of your options on this modification.

DaveK

iTrader: (21)

Competition only, though the car is built as a rally car so it's technically "street legal." 100% agree that this isn't a mod for a street car. As my standard disclaimer goes: don't try this at home kids.

I'll be posting up about the re-prep in the thread on my hillclimb car. You can check that out by following the link below:

https://www.evolutionm.net/forums/mo...0-edition.html


Dave

H-TUNER

Hillclimb car? Very interesting! Love to see the progrees on that!

DaveK

iTrader: (21)

Bumping this back up. After a bit of a rough year, I'm already in 2011 planning mode. While our new cooling system setup was improved over last year, I still feel like we don't have enough cooling capacity to support 500-600whp. I think at this point we're limited because our intercooler blocks 2/3s of the radiator, and there's no way around that. I'm also very seriously considering entering the car in the Euro style rallycross series, so I'm looking at the rear radiator thing again.

First thing I need to wrap my head around is line sizing. I used AN-16 for my setup this year. Since the rear setup will add ~20' of line, I'm trying to determine if I should be up-sizing to AN-20 lines, or if AN-16 is going to be adequate.

Second item is whether or not to add an electric water pump to the system back by the radiator. Wondering if this would be a "maybe needed" mod on the -16 lines, but a "definitely needed" on the -20? Any flow experts care to chime in?

Size_____I.D.____Wt./ft
AN-20___1.13"___0.25
AN-16___0.88"___0.20

So, the -20 has quite a sizeable cross-sectional difference, but does that matter at the flow rates the Evo will see? The weight difference is neglegable in my eyes. The main difference is cost. I've found suppliers for used/nearly new hose in -16, but it looks like I'd have to build everything from new parts if I go with the -20, which means $20/ft + ~$50-70 per fitting.

Thoughts?

Dave