R31 Rb20Det Drift Car Help

[Leeroy94]

I have a R31 skyline running a stock rb20det from a r32 with a JJR dump pipe. Its running dual thermos on a stock aus spec radiator (fairly old). Just did a track day with the following problems:

Engine won't rev over 5500rpm.

Radiator gets way to hot, at one point the water temp hit 115 degrees so I had to take it off the track to cool down.

Before fixing the revs problem, we need to address the cooling. In what order should I diagnose this problem so that it is most cost effective.

I was thinking something like:

1) flush radiator

2) check water pump functions properly

3) replace radiator

Should I remove the thermostat? Is getting some anti boil radiator additive worth it?

All suggestions welcome as I'm new to working on cars.

Can post photos if needed regarding the engine.

[GH05T]

might seem stupid, are the thermos on the right way around? decent thermos can pump backwards and everything heats up real quick, especially whith little airflow going sideways.

[Leeroy94]

Not a stupid question at all, in fact when I got the car one was facing so it was blowing in and the other was blowing out :s but both are now pushing air through the radiator and towards the engine.

[Dan_J]

1. double check all your heater hoses that come off the block and off the thermostat housing, very common to have a pin hole and it only pisses out when hot and sucks air in making the car run hotter

2. hose rad out with water to confirm its not restricted from a blockage

3.remove and check thermostat that it opens in boiling water

4.check that water pump rotors ( behind the thermostat) move when you spin it by hand with the fan belt off

5.might as well flush rad due to age

6. bleed coolant repetitively

for thermo fans the best type is the 'S' bladed fans as they pick up the air in a proper whirl wind where as the straight ones just are crap

Edited September 18, 2013 by Dan_J

[Leeroy94]

Ok thanks! I'll give these things a go and test them friday night at track.

Will update saturday with progress

[sweefu]

Just FYI, those standard R31 radiators are great, they have a good cooling capacity.

[Dan_J]

could just put heater to cold,disconnect thermo fan switch/fuse and rev it abit for awhile at home

[Leeroy94]

Unfortunately i live in one of those neighbourhoods where the retiree's living next door call the police if we even sneeze. And my car has no exhaust so its pretty loud. I'll have to wait till Friday

Any ideas on why it wont rev past that amount? It seems to spit and run rough over the 5000 mark, loses boost too.

[levinboy]

Check your coil packs bud

They may need replacing

[Leeroy94]

Ok, I'll check them out cheers!

[GH05T]

fuel preassure? not enough fuel will cause miss under load and running lean will heat things up.

[Leeroy94]

It's definitely running rich.. I can smell the fuel from the cabin. And it has some sort of resistor plugged in to the injectors that makes the ecu think the engine is running cold so it pumps more fuel in or something

[mad082]

For the heating side of things, first check the thermostat. Then check the radiator for cool spots. Basically, get the car warm and then run your hand over the radiator. If you feel spots that are cooler than other areas then the radiator is blocked and either needs replacing or the be professionally cleaned. Flushing the radiator does bugger all.

[Leeroy94]

It does this cold spot thing. So maybe I will give that a go. Do you thnk I should give it a go myself or just take it to a radiator place?

[GH05T]

It's definitely running rich.. I can smell the fuel from the cabin. And it has some sort of resistor plugged in to the injectors that makes the ecu think the engine is running cold so it pumps more fuel in or something

i had the low fuel rail preasure issue which is why i brought it up.

i could also smell fuel in the cabin which was the fuel return line or something not working right. this may be an issue if you can smell fuel.

coilpacks, fresh spark plugs, dyno for a propper check to see whats going on i recon.

[mad082]

It does this cold spot thing. So maybe I will give that a go. Do you thnk I should give it a go myself or just take it to a radiator place?

Take it to a radiator place, it isn't something that can be done at home. The cost of getting professionally cleaned may be close to that of a new radiator though, so it might be worth ringing and asking how much it will cost first.

[Leeroy94]

I've been quoted $280 delivered for a brand new aus spec r31 radiator. Is that a reasonable price?

Ill take it all apart tomorrow and take it in first thing Monday morning. Apparently they have a method of testing if its blocked or functioning fine at the shop.

[sweefu]

That's a pretty good price for a new genuine radiator mate, make sure you check the fan/shroud etc for damage.

After 25 years or however old the rad is, chances are it's going to be a bit rough. I'd recommend a new rad if you're hitting the track, for sure. Also hoses, thermostat etc. As bad as it is, I never used a thermostat in my R31 for the track (RB30).

[mad082]

I've been quoted $280 delivered for a brand new aus spec r31 radiator. Is that a reasonable price?

Ill take it all apart tomorrow and take it in first thing Monday morning. Apparently they have a method of testing if its blocked or functioning fine at the shop.

From what I gather, often they just tip some water out of a kettle through the radiator and feel for cold spots (pretty much the same method I suggested)

[Leeroy94]

So I took it in to the radiator shop. The guy said he has never seen a radiator that was so blocked in the 14 years of working there. Which is definitely a main factor in the overheating problem I've been having.