Project Thread Project SC400TT

[JBrady]

In revisiting the pic that Steve posted of Ryan's engine bay the feed and return radiator hoses pass right over and even wrap somewhat around the exhaust downpipe from the drivers side turbo. I would look very closely at finding another route for the hoses. Turbine housings, manifolds and downpipes often run RED hot+++ under load. Heating and reheating the water to and from the radiator is not going to help this issue.

 

[spf_lexus]

I have a boost pipe touching my radiator line just like John pointed out above. I know its not as big of a deal as a down pipe toching a radiator hose but if the hose was left as is... could it be fixed by wrapping the hose with nomex? I wondered if i could shed a few degrees by trying this.

 

[SC400TT]

I was going to suggest adding an auxillary radiator like XR8tt has. Cores come in countless sizes and shapes. One could be fit in a number of ways.

My next thought was a pusher fan mounted parallel to the road with a flap that would push UP and seal to a fabricated duct. The main duct would be like I posted already with the floor being the flap. Low speed, fan on, duct up and sealed creating a pressurized flow from under the car. At speed, fan off, flap drops and seals the pressure from the forward motion flow. Creates a pusher fan without creating any blockage at speed.

This morning thought of another way to "tackle" the problem. Build a shroud that uses the existing available space but then extends out and down (again using available space) leading to a parallel to the road PULLER fan(s). This would gain the needed plenum space between the core and the fans. This shrould should utilize blow out flaps so that forward motion flow would be able to exceed the fan outlet space as needed.

One of the concerns I had about enlarging the exhaust port area on your ported heads was that it would increase the surface area in the port thus increasing the transfer of exhaust port heat to the water jacket in the heads. It also slows the speed giving more time for transfer. The reduction in metal mass is hard to predict if that would be a net increase or not.

Ditto on XR8tt's tuning recommendation as too much retard will really increase exhaust temps as will too rich or combination.

Congrats to One Hot for getting Ryan's original system up and running. Hope he keeps everyone posted on its progress. Will be interesting to compare the two systems outputs as well...

Considering and looking into an auxilliary smaller radiator...Have not decided if I want to build a custom primary, ir just build and add a small secondary.

Good idea on the pusher fan...I may look into that.

I understand your concerns on the exhaust port porting, but, it is so mild, I do not think that is what is causing this issue...I think it is definitely airflow...When Darin first tuned it, I had no bumper cover or hood on the car, and temperature never even became an issue. Darin watched the temps. I drove it home over 25 miles, no overheating...As soon as I put the bumper cover on, it started overheating...The hood was still off, no matter. If I take the bumper cover back off, it does not overheat.

It's a little rich, but not too much...I do not think that is the issue.

Hey Ryan I got my 200A alternator at http://stores.ebay.com/Eagle-Auto-Electric?_trksid=p4340.l2563, they were recommended on supraforums and seem to have excellent customer service.

Thanks, looked it up...I may get one...Great prices too!

In revisiting the pic that Steve posted of Ryan's engine bay the feed and return radiator hoses pass right over and even wrap somewhat around the exhaust downpipe from the drivers side turbo. I would look very closely at finding another route for the hoses. Turbine housings, manifolds and downpipes often run RED hot+++ under load. Heating and reheating the water to and from the radiator is not going to help this issue.

Yep, I looked at that, so I wrapped all pipes with DEI Titanium wrap. Did not seem to make a difference. But, I may still reroute the pipe.

I have a boost pipe touching my radiator line just like John pointed out above. I know its not as big of a deal as a down pipe toching a radiator hose but if the hose was left as is... could it be fixed by wrapping the hose with nomex? I wondered if i could shed a few degrees by trying this.

I wrapped the DP's...

Thanks again guys...Keep the info coming...I have been working on the underside panels and venting all afternoon. I have some ideas...I will have to complete them and install them, and test it out. I will keep you updated.

Ryan

Ryan

 

[stevechumo]

Here comes 1 one of the 5 human senses that can tell you if the engine is overheating. If you can touch the engine bay frames with bare hands and hold on to them, then it's not overheating. But if you feel like it's burning your hands when you hold them, then it's definitely overheating. It's heat soak. The heat inside the engine bay isn't pushed out; therefore, it slowly soaks up to the surroundings. If the surroundings can be that hot, then the engine itself has the same destiny.

 

[BlackUZZ31]

sorry i'f this has been covered earlier but are all the under trays fitted and ducting that was removed when intercooler fitted replaced with custom item?

 

[SC400TT]

Well, I have been working on the overheating/cooling issue, and I have attatched pics of some of what I have done.

First of all, it is amazing to me that when I commission a professional to do a job for me, how many issues so frequently come up with their work...They frequently do ot do the work we agree to, or they cut corners, or they damage other parts of the car, etc...

The SC has plastic underbody panels to duct and direct air through the engine compartment...This is made by the manufacturer even for the stock car...So, when I add twin turbos, you would think they would be sure to work around the OEM parts so that they can still function as originally designed, unless those parts or systems are being modified or improved...


The underpanels consist of:

1. a front louvered panel which directs air up into the radiator/condensor chamber
2. an underengine panel which keeps air from either swirling under the car, exiting before it flows through the entire engine compartment, and forces the air to flow through to the back of the compartment and out
3. (2) Side Panels
4. a side panel on each side of the compartment that again forces the cooling air to flow through the entire bay and not exit before doing so.

The side panels were damaged on the driver side, due to obvious carelessness, and on the passenger side, totally missing. I am currently in the middle of properly marking and cutting out the necesary sections of the good side panels so that I can fit them back in and attach them correctly to the car.

The underpanels I kept, and I also bought new ones. I then modified the front panel because the FMIC is sitting too low to connect it to the bottom of the fron bumper cover. I had to cut the front section of the old one and rivet it to the new one so that I could mount it up to the new, lower Big Win Lip I molded to the OEM bumper. It turned out pretty good, I think.

I test fit is it, and it fits well.

I also added the OEM overflow from the SC300, I had to modify the bracket drastically to make it fit properly.

I also wrapped the DP's, the UP's, the manifolds, the mid pipe all the way to the back of the car...All DEI Titanium wrap.

I will soon test this set up and see how it works...

Front underside panles with the old one cut:

Finished product lengthened and riveted:

Spacer added to move the panel off the bottom of the FMIC...works very well:

Wrapped DP's:

Wrapped manifold:

More to come...


Ryan

 

[BlackUZZ31]

No under trays will do it! many a 7m in Mk III supras have died due to people not putting the under tray back on...

...If you want something done right do it yourself

depending on how your modified one go's you may want to try gaffa taping the louver holes off from under the inter-cooler back

 

[4U2QUIK]

No under trays will do it! many a 7m in Mk III supras have died due to people not putting the under tray back on...

Funny you mention that, I was just saying the same thing ti Ryan yesterday when he brought up the overheating issue.

 

[SC400TT]

No under trays will do it! many a 7m in Mk III supras have died due to people not putting the under tray back on...

...If you want something done right do it yourself

depending on how your modified one go's you may want to try gaffa taping the louver holes off from under the inter-cooler back

Funny you mention that, I was just saying the same thing ti Ryan yesterday when he brought up the overheating issue.

Thanks Guys...I have been talking about this somewhere in this thread, and I have been considering this as a potential issue for a few weeks now...

Ryan

 

[XR8tt]

Unless your "powering on" the fitment of turbo's shouldn't make it run hot...
Even with coolant line running close to hot parts it shouldn't over heat !!
Not a good idea tho...
Make sure air is well purged from system ...

 

[SC400TT]

It's an airflow problem...It did not overheat with the front bumper cover off. It did when I installed the cover. I have to address that to solve it.

Ryan

 

[SC400TT]

Success!!!

Well guys,

I finished up everything today...
I completed fabbing up all the parts that I needed to modify...I measured, dremeled and fit the side panels in place, I mounted up the underside panels and added 2 more spacers so that the louvered front underside panel would clear the whole length of the intercooler.

I barely had time to test drive my car (headlights are still not connected up), but I got the car up to temp, and it only once hit 50%. It never went above that, and it only got near it once while pushing the car a bit.... I am cautiously optimistic that I have resolved the issue by simply bringing my car back to OEM form regarding the underside body panels. What a significant difference. I will test the car more thoroughly tomorrow, and if all is well, I will work on tHe transmission set up and tune, and I will reschedule the dyno tune for a date real soon...

Lesson to all...tough to beat the stock, OEM engineering, and keep it intact whenever possible for most systems in the car...

Ryan

 

[JBrady]

Lesson to all...tough to beat the stock, OEM engineering, and keep it intact whenever possible for most systems in the car...

Ryan

Great advice!

 

[cribbj]

Ryan, so in the end you think it was only the belly pans? You still have your 14" Flex-A-Lites installed, too?

 

[SC400TT]

Ryan, so in the end you think it was only the belly pans? You still have your 14" Flex-A-Lites installed, too?

John, this appears to be the case. I will know tomorrow as I plan to drive it down the interstate to determine for sure...

Yes, the 14" Flex-A-Lites are still installed, with no shroud.

Ryan

 

[4U2QUIK]

Guess I better get all my panels back on before going turbo then....

 

[stevechumo]

You got my prayer! Once you start boosting for several times, it'll start getting hotter, if the heat isn't ventilated out.

 

[XR8tt]

Temps will / should only increase at low speed..
The fans "mainly" work at low speed due to air speed anyway..
If you need fans to cool over 40 mph...
You've got issues in your system..

If there's a rubber seal around rear of hood / bonnet??
A section can be removed to let hot air out...
Preferably not in front of drivers vision..
In case there's a hemorrhage in engine compartment...

 

[SC400TT]

You got my prayer! Once you start boosting for several times, it'll start getting hotter, if the heat isn't ventilated out.

I know what you mean...I am hoping that the upper hood vents are sufficient to vent it out. We will see...

Temps will / should only increase at low speed..
The fans "mainly" work at low speed due to air speed anyway..
If you need fans to cool over 40 mph...
You've got issues in your system..

If there's a rubber seal around rear of hood / bonnet??
A section can be removed to let hot air out...
Preferably not in front of drivers vision..
In case there's a hemorrhage in engine compartment...

That was the problem...Even the AAP Fans and shroud were sufficient for idling and very easy and slow driving...But, I was overheating above 40 mph...The shroud was a part of that problem as it "deadheaded" the air and it could not get out of the radiator compartment...Plus the underbody panels were a big problem by not being properly installed, infact, not being installed at all...

I have had several suggest removing that weather stripping...I prefer not to do so. That is another reason why I vented the hood...we will see if it is enough.

Ryan

 

[SC400TT]

Overheating/Cooling

It is amazing how critical the stock set up is to ensuring proper cooling of the drivetrain of the SC...Especially the SC400. When I first started examining this issue, I looked closely at every aspect that Lexus had engineered...and removing the stock fan and radiator would mean that anything I modded would require me to pay close attention to the efficiency of those mods...I did not do so enough, I thought I had, but I had not. So overheating become an issue as soon as I placed the bumper cover on my car. The nose of the SC is not very conducive to proper airflow...Look at most cars, and you will notice 2 distinct similarities almost immediately...They all have a lower air dam section to vent air into the radiator, plus in most cases, they have a large grill that covers an area very close to the overall size of the upper half of the radiator compartment. These 2 components ensure proper air flow to the cooling system of the vehicles.

The SC does not have an upper grill, so directing sufficient volume of air into the cooling system is critical by other means...That is why the underbody panels are crucial to proper functioning of the cooling system. This becomes even more essential with the addition of
turbos into the front of the engine bay...the additional plumbing, removal of OEM heat shields, lack of room, etc, add to the need for sufficient air flow. Turbos add a whole lot of heat...even when ceramic coated and wrapped...be sure your (2) plastic side underbody panels are completely intact, and that they are installed and custom fitted around the
additional intercooler plumbing. Be sure the louvered and flat tray underside panels are installed and attached properly too as they all work together to create a very effective air compartment that not only catches the necessary volume of air needed to cool the system, but also to force and direct the air to flow through the engine compartment and out so that there is no heatsoak.

Use your underbody panels guys and gals...

Ryan