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Fin count is a function of where you intend to operate. Dusty, muddy, dirty environments will not suffer high fin counts, they'll clog and overheat everytime.
Congratulations on the lap times and collection of hardware!
Honestly, I’m a bit surprised at the struggles with water temp. With your air flow mods, I figured that’d be a non issue. It’s also interesting that your oil temps are solid and seemingly low.
One thought and somethingI experiences previously. What radiator cap are you using? Yes, Denso/Koyo makes the OE radiator. And yes, the caps looks crazy similar and you can fit the OE one on the radiator, but in my IS300, they are ever so different for sealing diameter and height. I want to say in the fine print somewhere, Koyo states you have to use their cap. In short, I didn’t use the Koyo cap and it wouldn’t allow the system to pressurize and burp properly.
if that’s not it, I question if you have a water side issue. And unfortunately the first that comes to mind is head gasket...
Nice work out there, we were gonna come out and spectate, but just too tired from the full work week and Gridlife the weekend prior.
Kos- I was looking for you guys, it was a real good time the whole weekend shoulda come out.
So speaking with a good friend lastnight that builds performance rads and he said hes down to help. I need to get a stock radiator for dimension testing, does anyone have one laying around that they will sell for cheap?
Clear radiator flow path helps but is not critical. The company I am working with has the ability to manufacture different riffle and tube designs as well as flow and pitch. This is critical when stacking elements in front of one another. AC condenser doesn't help to be there but there is no where else to put it. So your only option is to maximize the riffles and tube for the speed and flow volume that is hitting it, this is where the magic lies apparently, and they have pulled off quite a bit of magic using this tech to cool racecars that are stacking 4 inch intercoolers and oil coolers in front of a radiator. I was assured we could come up with a solution and I wouldn't have to move anything around.
One thought and something I experiences previously. What radiator cap are you using? Yes, Denso/Koyo makes the OE radiator. And yes, the caps looks crazy similar and you can fit the OE one on the radiator, but in my IS300, they are ever so different for sealing diameter and height. I want to say in the fine print somewhere, Koyo states you have to use their cap. In short, I didn’t use the Koyo cap and it wouldn’t allow the system to pressurize and burp properly.
So having moved the pressure bladder and using a non OEM part im a bit off the reservation on the cap thing, My cap is a MotoRad 15 psi that fits on top of the new pressure bladder. I have actually used this cap on my other racecar (like exact same cap) I suppose it could be different than what is required on the new bladder but it is bleeding coolant into the non-pressurized bladder and back only above 205F and on cool down, which is right. As far as HG issues- oil looks fine and i am not losing any level. I'm going to do an oil change in the next couple day so ill be double checking this again but i don't think thats it (fingers crossed). I DO think these cars tend to run hot when at the upper end of the rev range, but does anyone else have data from on-track of what their water temps are when ambient is above 90F? I'm wondering if its just a matter of 'now i can see the numbers...' Ive been told in the past that oil temps are king and if they look good then water temps are more of a suggestion. I dont know how much i wanna believe that though.
The OEM gauge never moved off center on mine even at 102F at CMP with my oil temp pushing 275F. The OEM gauge certainly isn't the best arbiter of overheating, but with the modifications you've made to the system it's very possible the cap isn't in an ideal place.
Wish I had actual data, but I didn't have the tools when I was tracking the car. It was also very stock at the time.
Changed the oil last night, good news is there was nothing milky coming out and coolant levels hadn't changed from where they were last time. I did pull a sample and sent it off to Blackstone Labs to be tested for coolant, so i will know definitively in a week or so.
In other news I drained my 1qt catch can after modding the blow by pick up valve port to add the larger hose.
I ran about 15 laps, 12 of those at full tilt session speeds. I checked the can level and added oil to the motor when needed but purposely did not empty the catch can all weekend.
Drumroll
Almost exactly 12 Oz of blow-by accumulated FOR THE WHOLE DAY. That is only 0.375 of the catch can capacity. This is orders of magnitude better than before I modded the separator box air outlet (same motor, same oil). Before I would be emptying the RR can after each session OR the new 1qt catch can would be half full after 4-5 hard laps.
I'm happy with this outcome, It means I don't have to mess around with it until I do my post track day maintenance when i'm back in my garage.
Now that I KNOW for a fact its not the Head Gaskets im going forward with the initial processes of custom building a radiator for hardcore tracking Lexus ISF's. Wer'e confident we can build something that will work with minimum increase of 40% efficiency using newer technology tube and riffle design as well as different construction metals. I picked up and OEM rad and its going off soon to get measured and engineered. Ill update the progress as it happens.
Until then I bought 3 different style radiator caps. All are recovery type caps so they are designed for my system layout but all have slight differences in design that I am curious to try. I have an event coming up this Friday and will swap them out to see if there is any noticeable differences in the data. Granted its going to be a whole lot cooler this week than it has been lately.
Honestly, no not really. That single bumper vent isn't going to flow more air than a seal duct system, not enough to get me from where I am now to a car that runs 20* cooler under load. The majority of the flow for that vent is also just flowing air directly onto the radiator vertical and cross supports. As far a t-stat i remember swapping it out to an OEM lexus part but I can't find any pictures of me actually doing it. Strange. Im going to order another one and throw it in just to be sure. I can take a look but does anyone know what the OEM ISF one opens at? and is there a replacement one that is know to fit and opens only slightly lower? im not a big fan of this- but im curious if there is any out there people have been using.
Thanks guys, Thats exactly what I figured. It looks to be a standardized part across tons of Toyota platforms. I searched the PN# in my email and didn't come up with a receipt for one, so unless I bought on at the dealership when picking up coolant its possible that i didn't change mine for some reason. I just ordered it and will throw it on the car- if not before this Friday then for sure by the next event on the 31st. I don't think its the issue since warm-up and normal driving condition temps are extremely consistent in the data logs- but once the temps get over 210 its runs way up to 225+ if I stay in it. Classic heat overload scenario. It most likely wont be an issue tracking weather under under 75* this winter, but all the same I refuse to drive a car where I have to keep one eye on temps. I will solve this.
If the thermostat were stuck open it would be throwing a CEL for coolant code P0128
Also too cool might trip up other issues if the system is not a proper operating temps..
Joe Z
I had a strange issue on my ae86 in the past where the tstat was opening late (like up around 210f) and once it was that hot it was a losing battle cooling it back down- especially if I was on track. In this case i don't think that's the issue as I physically touch the coolant lines I'd plumbed to the aluminum bladder to feel at what temps they heat up then correlate it with the displayed temps, 180f seems to be right on the money.
Not sure if this is a help, but this is how the factory envisions the system working.
The term "bladder" is confusing. Bladders expand and contract to suit the volume. There are no bladders in this system, but there is a tank used to allow expansion and contraction of coolant and it has a pressurized cap on it. Did the replacement mimic the original design, or was it based on the previous concept of using the cap to set pressure and the expansion tank to be unpressurized to allow the expansion and contraction of the coolant? The way these two systems work isn't even close to comparable. I'll be first to admit my familiarity with the old school approach, and my wonder at using a pressurized plastic reservoir on the IS F for coolant. It was a first for me. It's possible this also existed on the '06 IS350 I owned, but I don't remember this being the case. Wait - just confirmed with TIS, the '06 IS350 had a conventional system, so this pressurized reservoir is "new" for the '08 IS F.
10-13-20, 04:52 PM
