Jump to content
  • Welcome to 205GTIDrivers.com!

    Hello dear visitor! Feel free to browse but we invite you to register completely free of charge in order to enjoy the full functionality of the website.

lahondal

205 Turbo Overheating, ignition related?

Recommended Posts

lahondal

Hi! 

 

Today have raced the 205 turbo 8v on a hot day (30C°) and long (7km) hillclimb. Very first race since a complete engine rebuild. 

 

Car was not raced too much at all as in the previous event, engine overheated to 107C°, then a cap in the expansion tank pop out, coolant everywhere, sucking coolant throught inlet and ended throwing a rod, complete disaster. 

 

Now as the radiator was a STD diesel unit we thought that the radiator was too small and managed to fit a Bmw E36M unit, a massive radiator that fills almost all the front hole from top to bottom. 

 

Well, so now driving the car only for a spin it runs at thermostat limit (82°C), so the radiator its doing his job fantastically. But today in race, it have reached 110°C and that shouldnt be anywhere of normal in my eyes with that massive radiator. 

 

Car haves a lot of mods that should be taking it to at least +260hp as seen in others in this forum, but it struggles to make 227hp and starting to think the ignition and/or fuel map is wrong or at least very conservative using retarded ignition.

 

Can a retarded ignition cause SO BAD overheating? We are now in a no-way road as in any way can fit a bigger radiator, but cant race the car at 105-110°C either. 

 

We have a Ecumaster black, catcams turbocam, gt2560r, custom manifold, 3"  straight exhaust, 57mm TB, front mishimoto IC (the good not the cheap one) and some more mods. 

Share this post


Link to post
Share on other sites
Thijs_Rallye

There are many parameters that can have an influence on ICE heat generation.

 

Do you monitor AFR with a wideband and if so, what AFR are you running? What brand of wideband are you using? Is the cam timing set to the specification?

 

I assume you had it on a dyno, was this dyno capable of measuring steady state? If so you should be able to reproduce the problem on the dyno.

 

You could post the fuel target map and ignition map, but since I have little experience with the tct engine I can't say if the ignition values make sense but someone else likely will.

Share this post


Link to post
Share on other sites
welshpug

Loads of conversions like this suffer from oversized intercoolers blocking  airflow to the radiator, and no ducting to keep the air going where you want it.

 

Cap should  have been fine to past 107, the warning light doesnt come on till 110 and boiling point at +1bar is 125°,   TD cap is 1.4 bar which knocks is over 130°

 

 

Do you have afr and egt?   

Share this post


Link to post
Share on other sites
petert
Posted (edited)

What ignition timing does it run at max load, full boost? How much boost? What CR? What fuel?

Edited by petert

Share this post


Link to post
Share on other sites
lahondal

Well, there are couple of questions i dont have answer for, as the car was mapped on a dyno (inertial type), and the map its password protected so cant access to ignition or fuel specs.

 

We use to had a wideband but the sensor died soon and as the ecu is running in closed loop didnt replace it. 

 

I attached a pic of the cooling setup. Have a new mishimoto radiator to replace the OEM m3 copper unit already. 

 

Dont know how to make ducting to the radiator as there is literally no space.

 

 

IMG_20220620_184613.jpg

Share this post


Link to post
Share on other sites
petert
Posted (edited)

When you're doing stuff like this you really need to log all the channels so you can view what's going on. Do you have a datalogger? Internal or external to the ecu?

I've been looking at a Cosworth RS500 radiator. They look almost perfect, less the mounting wings etc. Also move the outlet to the side. Simple fab jobs.

 

You really need to be on top of the AFR's. When you say closed loop, do you mean 14.7:1? As that is way too lean. You should be down at 12:1 max. Log that too.

 

You're in Spain? Why aren't you running E85?

Edited by petert

Share this post


Link to post
Share on other sites
SRDT

Are you running a single fan on the radiator? Also is the fan made to be behind the radiator? It's not enough to reverse the polarity if you want to put in the the other side.

Share this post


Link to post
Share on other sites
petert
3 minutes ago, SRDT said:

Are you running a single fan on the radiator? Also is the fan made to be behind the radiator? It's not enough to reverse the polarity if you want to put in the the other side.

In a race however, the fan should have no effect on cooling. That's just for the pits.

Share this post


Link to post
Share on other sites
Tom Fenton

It is worth the time and effort fitting ducting or blanks to fill in any gaps between radiator and bodywork. The cooling air will take the easiest route so it will flow around the radiator rather than through it if possible. From experience it does make a difference so you need to seal from the rad to front panel sideways. And from the front bumper back to the rad. So all the air that comes in the front MUST go through the radiator.

Share this post


Link to post
Share on other sites
mmt

Impresssive cooling setup.
 

Do you guys have any pictures af How the ducting Can be done? 
 

My Oil is getting hot and I have tried to make some ducting - not sure it Will make much of a difference though- next race is after summer break. Temp was fine on the dyno but Racing cooked the Oil - was 125-130 c after 4 laps. 
 

Mine is a n/a engine. 


thanks. 

Share this post


Link to post
Share on other sites
lahondal
11 hours ago, petert said:

When you're doing stuff like this you really need to log all the channels so you can view what's going on. Do you have a datalogger? Internal or external to the ecu?

I've been looking at a Cosworth RS500 radiator. They look almost perfect, less the mounting wings etc. Also move the outlet to the side. Simple fab jobs.

 

You really need to be on top of the AFR's. When you say closed loop, do you mean 14.7:1? As that is way too lean. You should be down at 12:1 max. Log that too.

 

You're in Spain? Why aren't you running E85?

When i mean closed loop i mean that the ecu is completely following the fuel maps instead of using the wideband to compensate for little variations in afr due to temp or atm pressure. 

 

There is not E85 at the petrol stations here. But dont thought to use E85, we are using 98+bardhal additive at the moment. 

 

Buy a new sensor for the wideband and add an oil temp sensor seems to be the way to go to find where the problem is as we dont have a datalogger at the moment and the ecu is protected. 

5 hours ago, Tom Fenton said:

It is worth the time and effort fitting ducting or blanks to fill in any gaps between radiator and bodywork. The cooling air will take the easiest route so it will flow around the radiator rather than through it if possible. From experience it does make a difference so you need to seal from the rad to front panel sideways. And from the front bumper back to the rad. So all the air that comes in the front MUST go through the radiator.

This make sense so will try that for the next race. Will post some pics when finished. 

 

Anyway will phone the mapper tomorrow to tell the problem we have to know what he think about. 

Share this post


Link to post
Share on other sites
Type-R

According to the theory ignition retard would put heat in to the exhaust, ignition advance would put heat in to the cooling system.

Share this post


Link to post
Share on other sites
petert
Posted (edited)
1 hour ago, lahondal said:

When i mean closed loop i mean that the ecu is completely following the fuel maps instead of using the wideband to compensate for little variations in afr due to temp or atm pressure.

That is open loop. In closed loop mode, the ecu will lock onto 14.7, provided the maps are within tolerance to get there.

 

I also think your oil cooler is a bit small for a wet sump engine. I use the same size on a dry sump system, which runs a lot cooler. When I was running wet sump with 250+ hp, I'd typically see 120ºC on the oil with a 16 row cooler. Now it's 100-105ºC with a 13 row.

 

You should also consider datalogging the pressure in the cooling system. Then you'd be able to identify a blown headgasket easily.

Edited by petert

Share this post


Link to post
Share on other sites
lahondal

I misunderstood then. 

 

The engine is brand new rebuild, first race with only 20km so no headgasket i think. 

Share this post


Link to post
Share on other sites
lahondal

We are STILL having cooling problems. 

 

4km hillclimb, 26°C ambient temp. Start of the race 87°, and finish at 105°.

 

We have tried so far:

 

-Panelled rad to fill gaps at sides an on the top. 

-Fit a restrictor on return from thermostat to pump hose. 

-Ditch the turbo cooling to aid. 

-Change cooling fluid to Mocool race fluid. 

 

No aparent upgrade here. Dont know what to do now. 

Share this post


Link to post
Share on other sites
Tom Fenton

I’m not sure that 105 deg C is really that much of a problem in a pressurised system. Certainly my wife’s Mini Cooper S does not turn on the low speed cooling fan till 105 C (factory setting)

Share this post


Link to post
Share on other sites
lahondal

I would be happy if the temp stops there, but with a longer track the temp keeps climbing 110+

Share this post


Link to post
Share on other sites
wicked

Since you already swapped radiators and behavior did not change, the radiator is likely ok.

Did you check your water pump? If the coolant does not circulate fast enough, you cooling capacity is limited, which will only show up on full load. 

Some pumps have plastic scoops and those sometimes loose a scoop. 

Edit: are you sure it exactly the correct pump?

 

Tbh, I would not ditch the turbo cooling on a hill climb car... 

Edited by wicked

Share this post


Link to post
Share on other sites
lahondal
5 hours ago, wicked said:

Since you already swapped radiators and behavior did not change, the radiator is likely ok.

Did you check your water pump? If the coolant does not circulate fast enough, you cooling capacity is limited, which will only show up on full load. 

Some pumps have plastic scoops and those sometimes loose a scoop. 

Edit: are you sure it exactly the correct pump?

 

Tbh, I would not ditch the turbo cooling on a hill climb car... 

Water pump is "almost" new. Probably have no more than 200km. Fitted new in previous rebuild (not in the last). 

 

What warns me is that comment about the correct one. Didnt remember exactly but there is a specific water pump for xu10 engines? That will blow my mind. 

 

3 hours ago, petert said:

Are there any other high octane fuels available to you?

eg

https://www.vpracing.com.au/collections/unleaded-racing-fuels/products/ms109-reg

 

 

My theory being, try some 108-110 octane unleaded fuel and see if the problem still exists.

We are using 98 octane + bardahl additive to improve octane rating (more for peace of mind than other reason). 

Share this post


Link to post
Share on other sites
DamirGTI

Possibly the pump design is "bad" ie. is ok. for std. engine but can't cope with the heat generated from such high modified engine .

 

They don't cost so much , and aren't hard to replace .. i'd give it a try .

 

Pick best quality water pump , "Hepu" pumps are some of the best ones (no difference between NA XU10 8v pump and turbo item as far as i know) .

 

Cheap low quality pumps often have poor impeller designs , and often pretty big clearance between the pump body and the impeller - you want as close as possible tight fit/less clearance impeller-to-pump body ... that'll improve water pump pumping volume , and maintain/increase coolant pressure within the block and head  - from mid to high revs it's the pressure created by the water pump which takes away/reduces combustion heat and prevents coolant boiling , not the expansion bottle cap .

 

With regards to the fueling , i gave up on "octane boosters" long time ago ! more often than not they're useless .

 

Get some "Xylene" or "Toluene" , it'll be cheaper and far more effective than spending money on fancy "snake oil bottles" , mix up some with the 98 petrol and you'll be surprised with the result especially on an turbo engine ! even more if you can play with the ignition advance afterwards .

 

D

Share this post


Link to post
Share on other sites
petert

I’m suggesting jumping to 108-110, not 99. If it suddenly runs cooler, you’ll know it’s tuning related. 

Share this post


Link to post
Share on other sites
lahondal
1 hour ago, DamirGTI said:

Possibly the pump design is "bad" ie. is ok. for std. engine but can't cope with the heat generated from such high modified engine .

 

They don't cost so much , and aren't hard to replace .. i'd give it a try .

 

Pick best quality water pump , "Hepu" pumps are some of the best ones (no difference between NA XU10 8v pump and turbo item as far as i know) .

 

Cheap low quality pumps often have poor impeller designs , and often pretty big clearance between the pump body and the impeller - you want as close as possible tight fit/less clearance impeller-to-pump body ... that'll improve water pump pumping volume , and maintain/increase coolant pressure within the block and head  - from mid to high revs it's the pressure created by the water pump which takes away/reduces combustion heat and prevents coolant boiling , not the expansion bottle cap .

 

With regards to the fueling , i gave up on "octane boosters" long time ago ! more often than not they're useless .

 

Get some "Xylene" or "Toluene" , it'll be cheaper and far more effective than spending money on fancy "snake oil bottles" , mix up some with the 98 petrol and you'll be surprised with the result especially on an turbo engine ! even more if you can play with the ignition advance afterwards .

 

D

A really appreciate your comment. ATM dont know if i have fitted a 1.9gti pump on the iron block, should take it out and check. Seems to be 60mm in diameter and original turbo unit is 68mm. Only that alone must be a BIG tolerance problem and hence performance issue. 

 

Next step, check the waterpump. 

18 minutes ago, petert said:

I’m suggesting jumping to 108-110, not 99. If it suddenly runs cooler, you’ll know it’s tuning related. 

Will solve the waterpump doubt first, then this will be the next thing to try. 

 

Will post results then if that can help someone. 

Share this post


Link to post
Share on other sites
DamirGTI

Yes , alu. block water pumps are 60mm , for iron blocks are bigger - 68 or 69mm dia. pumps .

 

Fingers cross it's simply the wrong dia. pump !

D

 

 

Share this post


Link to post
Share on other sites
lahondal

So just pulled the waterpump, its the right diameter and works perfect. 

 

Im absolutely empty of ideas then. 

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×