PTYIS2

So continuing with the preparation for my next track day, i ordered recently RR-Racing AOS.

I know there have been a debate of wether this have any impact on performance, but based that my car, which i bought 17 month ago and had only 7,000 miles at that time, and since day one its what Rafy from RR calls "KCLV Challenge" car, because it had never gone over 16 on the KCLV (low or high), I want to assume is because of oil and gases from the PVC system going into to the intake and burning with fuel lowering its octane, maybe causing knocking and obviously the ECU retarding the ignition timing. (have been discussed a lot on this forum).

So i have decided to use AOS and see if its helps me improve the KCLV of my ISF....... but wait......... since must likely there is carbon builtup on the valves seats, i want to try to clean it first, heres were the title of the thread comes....... have anybody tried Sea Foam thru the throttle body on a IS-F (RR have used on IS350´s) ? is it safe? (Lance, i know you have a different opinion on how to get rid of the carbon buildup) Feedback is welcome.

After doing/or not the Sea Foam ill install the AOS, will do a oil change and start monitoring KCLV, its everything works as expected KCLV should go up....hopefully..... and if the theory os correct it should maintain high because of the AOS.

Jp

Leander311

iTrader: (2)

Just like the IS350, you're aware we have both DI and PFI on the F, right? Which practically absolves us of the valve/IM carbon fouling issues plaguing the IS250's DI-only mill...

Instead of running the risk of fouling the GESi high-flow cats for which I'd just paid $1k installed, I'm personally a fan of using Top-Tier fuel, and every 3-4 months dumping in something high in PEA - either Gumout w/Regane, or even better, Redline SI-1 (got a case of 12 on Amazon for $100).

-Nick

jdmSW20

iTrader: (12)

I'll co sign this as well, I do the same over here with my car as well

semnosNSX

I tried the sea foam method as per the recommendation of Ravi on another thread. Afterwards, I didn't datalog as I should have, but I also didn't notice any difference at all from a driving perspective.

lobuxracer

iTrader: (2)

KCLV challenge is more related to manufacturing tolerances than to the fuel you are using if you see the same results regardless of which fuel you run.

I have seen deck height problems that caused horrible detonation when it should never have occurred. I suspect because the 2UR-GSE has angled squish that even small deviations from ideal with deck height/cylinder head thickness could cause huge problems with detonation resistance.

When I build an engine, the most critical measurement is squish height. It is mechanical octane. If it is too tall (the default factory setting because it will not lead to warranty claims), the engine will be inefficient, and will fail to make good power. If it is too short, it will cause piston to head clearance problems, and may cause failure which would be typically a warranty claim.

Without disassembling the engine and measuring the squish, it is impossible to be sure what the root cause of "KCLV challenged" is. I would bet a whole lot of money it has a lot to do with the mechanical dimensions of the engine as built by the factory.

semnosNSX

Mic drop.....

Leander311

iTrader: (2)

PTYIS2

so if we wanted to validate both hypothesis(squish/carbon build-up), for the Mechanical (squish) one, Ill have to tear apart the engine, which is not something thats easy to do, at lest for me.

In the case of the other hypothesis, Carbon Build-up because of the oil been recirculated by the PVC System, is as simpler and actionable way to test it.
1. looking if there is build-up, (i have a digital brescope for doing this)
2. if yes, then get rid of it....going back to the thread question, should i use Sea Foam, (any other recommendation?)
3. make sure there is no new build-up, thats the reason for installing RRR AOS.

Thoughts?

Kodiak303

lobuxracer

iTrader: (2)

I am not sure who your resources are, but this is what Lexus published about what I call angled squish. Truth be told, if this is intended to be squish area, their tolerances for deck height, stroke, rod length, bearing fit, and piston height from the pin are going to need to be much tighter than anything I've seen from an OEM. I pretty much doubt that is the case, but I have not had a 2UR-GSE head and block to measure. Given how often manufacturers can't even get valve seats concentric with ports, I have my strongest doubts these measurements are held as tightly as they would be in an ideal world.

From the New Car Features:

Leander311

iTrader: (2)

I'd recalled from my graduate ICE class (taught by SAE Fellow) that pentroof designs typically don't utilize squish, because there's simply not room for it... Here's a solid text that makes the same reference, though taper squish may be a different concept entirely. The text also btw has a fantastic intro about the verrrrry early, circa 1903, improvements to the ICE.

Leander311

iTrader: (2)

From the link above: "In fact, in practical open‐chamber four‐valve pent‐roof engines, squish is a minor factor. There is simply no room with four valves and a spark‐plug to have any significant squish area."

2013FSport

iTrader: (2)

OP grab one of those micro sized usb boroscopes and snake it down the intake via the TB. You can inspect a few valves that way.

They make Wifi ones now that connect to anything and easily fit down a 5/8" plug hole. Problem solved!

I find that keeping the port velocity up tends to keep the valves and CC clean. I do run Techron 3x a year for kicks but thats it...

lobuxracer

iTrader: (2)

And yet when I correctly set the deck height in my air-cooled 1.2 liter Yamaha for 1mm squish, I was able to raise the compression ratio from measured 9.2:1 (factory claimed 9.5) to 11.25:1 and still easily run on California 93 octane fuel from the early 90's. All this while reducing full advance ignition timing from 28 to 17 degrees on an engine with 35mm Keihin CRs, not direct injection, and ending up with somewhere north of 160hp.

I won't argue with engineering backed by solid data acquisition, but my empirical results don't reflect the idea that squish in a classic pentroof design is inconsequential. Dead giveaway on the squish performing as expected was no carbon on the squish areas of the pistons or head.

blackisF08

iTrader: (2)

i dont understand why people are so worried about their kclv values