head porting and gas flowing for isf in the UK and known power gains?

[A's F-word]

Hey guys has anyone done this to their isf... in the old days this is what we did to gain 15 plus bhp from 2 litre track cars and made for smoother acceleration through the rev range.

[Toothy]

Our engines are tuned by Yamaha and hand built and to very high tolerances, with quality materials (like titanium valves). I doubt much could be done to improve power.

More info on our engines from the US forum.
https://www.clublexus.com/forums/attachments/is-f-2008-2014/381480d1457762736-help-with-understanding-the-isf-engine-construction-isf-engine_story.pdf

Someone please tell me I'm wrong, but think we already have as good as you get!

[paul99]

Wouldn't that require an ecu remap as well, sounds very expensive for possibly little gain, I gather the ISF engine is very optimized anyway. From what I've read the exhaust sounds like a good place to focus on if your after decent proven gains. 

[A's F-word]

I've already got a custom system and removed one of the cats... I will do headers and air induction system but really begrudge doing a tune via a company in the states rather than on a dyno infront of me..

I looked into turbo and S/C but cost etc is difficult to justify to the Mrs. Admittedly I do miss a turbo as my 161 aristo was so easy to tune.

[lotusdave]

well, don't tell the Mrs and stick a supercharger on it. 

[A's F-word]

4 hours ago, lotusdave said:

well, don't tell the Mrs and stick a supercharger on it. 

Hahaha I think she may cotton on to the 10k plus dent in the bank account

[Big Rat]

@A's F-word Andrew do it..............." With wives it's much easier seeking forgiveness than permission " 

Big Rat

[Jgtcracer]

Don't bother porting heads, that's something that's fine way down the line once bolt ons are done, I've done it in the past to get small gains but were on smaller higher revving Honda engine!!

Times have moved on, casting techniques are much better and it would cost a fortune but the time there removed, flow tested on the bench then ported before re-fitting.  

Exhaust/manifold mods would be far better.

Obviously all my opinion but kind of makes sense

Marcus

[peachy]

It will do next to nothing on an ISF. and the very small gains it produced (if any) would never be noticed.

The ISF is a properly quick car as standard. Why spend a fortune in trying to make it slightly quicker.

Some people are never satisfied. You can give them the moon and the sun and they would want the stars to go with it.

[lotusdave]

20 hours ago, A's F-word said:

Hahaha I think she may cotton on to the 10k plus dent in the bank account

But darling, its my tax year end pension contribution. I did it for the tax relief and our financial future.

[Guest]

You can give them the moon and the sun and they would want the stars to go with it.

They come as a package anyway.


Sent from my STV100-4 using Tapatalk

[A's F-word]

20 hours ago, peachy said:

It will do next to nothing on an ISF. and the very small gains it produced (if any) would never be noticed.

The ISF is a properly quick car as standard. Why spend a fortune in trying to make it slightly quicker.

Some people are never satisfied. You can give them the moon and the sun and they would want the stars to go with it.

Lexus purposely restricted the ISF engines performance so that they did not need to force induction the GSF.

The torque and performance aren't the moon and sun type of figures especially when they graced us with the 2JZ vvti twin turbo that could achieve amazing stuff with minimal effort 2 decades prior to the isf. We all know in reality bhp should be nearer to 100 bhp per litre and figures exceeding 400lb ft of torque.

[A's F-word]

21 hours ago, Jgtcracer said:

Don't bother porting heads, that's something that's fine way down the line once bolt ons are done, I've done it in the past to get small gains but were on smaller higher revving Honda engine!!

Times have moved on, casting techniques are much better and it would cost a fortune but the time there removed, flow tested on the bench then ported before re-fitting.  

Exhaust/manifold mods would be far better.

Obviously all my opinion but kind of makes sense

Marcus

Hey Marcus

I am going to do the headers but was just seeing if there was a point of doing the old school stuff.

You basically confirmed what I suspected but I you don't ask you don't find out.

I had a s2000 amongst my history of jap hi performers... and some German cars of old to recent so different mods suit different engines and set ups.

Just want to avoid a supercharger until it is not such a monopoly and prices become more competitive. A turbo setup may prove to be a bit laggy especially under a auto setup.

 

[Guest]

Lexus purposely restricted the ISF engines performance so that they did not need to force induction the GSF.

Can you explain this more?

Sent from my STV100-4 using Tapatalk

[lotusdave]

1 hour ago, Comedian said:

 

 

Can you explain this more?

Sent from my STV100-4 using Tapatalk
 

 

seems unlikely given the age of the isf.  

[Martin F]

2 hours ago, lotusdave said:

seems unlikely given the age of the isf.  

My thoughts as well. 

[mrfunex]

Given that the GSF hadn’t been dreamed up when the ISF’s design was being finalised, I find the claim that the ISF was held back to stop it stepping on the toes of its big brother unlikely...

Yamaha did a pretty good job with the intakes on the ISF, I’d imagine any gains by polishing etc to be negligible - worth a play if you’re interested in that kind of thing though. The ECU will relearn any subtle changes, so a remap ought not to be required. The OEM exhaust is, however, a bit restrictive. It has a flat section to get it past the back axle - proper aftermarket ones maybe release 10bhp or so...

[Guest]

10 hours ago, Martin F said:

My thoughts as well. 

I would like to hear the story 

 

[A's F-word]

You can not honestly believe that the GET was the after thought when throughout it's history the GS range has always had the daddy engine like is300 was non turbo 2jz and the GSV300 aka Aristo had the most famous and desirable engine.... if aftermarket headers and systems gain more performance do you seriously believe that Lexus and Yamaha did not also know this... but if the isf and GSF had the exact same power but being the GSF is heavier they would be heavily cricised for it and would have been made to do what Merc did and slap a s/c on it do separate big and little brother. (C class and e class or clk and cl). Manufacturers always think about the next sale as they should but being the isf was a flagship all the guns should have been out.

[A's F-word]

GSf not GET lol stupid auto correct haha

[A's F-word]

Don't get me wrong I love my little V8 and I have owned many high performance cars but you would hope that companies would look to at least achieve near as 100 bhp per litre and healthy torque through the rev range especially when the company has a history of achieving it.

[mrfunex]

The engine in the GSF, albeit similar, is not the same as the ISF, nor is the ISF ‘strangled’. The ISF was very good for the day; the GSF is approximately 8 years newer - engines move on.

 

The newer 2UR-GSE uses different materials, a higher compression rate, a higher pressure DI fuel system. It revs higher as it’s slight better balanced, has slightly larger valves and a better designed cooling system. The exhaust system and intake are different. It’s still a 5.0 V8, but not many parts are interchangeable. 

The LC500 *does* use the same engine as the GSF and the RCF, by with a twin air intake  this liberates another 4bhp.

 

You can read (depending on your skill at Japanese!) up on it here... some of the diagrams are self-explanatory.

[A's F-word]

The difference is the same as saying when the 2jz went vvti of course they progress otherwise we need to revolt against them lol but it is restrictive in the isf otherwise why would you automatically gain so much more power and rev range from a N/A car... simple question is why can BMW achieve similar power from a 4 litre and from a 5 so much more. This was nothing to do with emissions was simply the boat was not entirely pushed out. I know the engines have a difference my point is from a performance aspect...

My Japanese has slipped slightly  lol but I have built my fair share of grey imports to know where they hold back but usually it's a simple improve to make the engine and car a thing to make the Germans tremble... sadly not anymore.

[FTBBCVoodoo]

I personally think it was built to remain reliable and within the same bhp bracket as it's rivals.

At the time the E90 M3 4.0 produced 400bhp, the RS4 4.2 about 420bhp (claimed before they coked up and were slower than death) and the C63 about 450bhp from a 6.3 (which going on the theory of a holding back an engine is probably the worst culprit and even in uprated form for the SLS had just over 500bhp - I think)

In terms of tuning your ISF.  If the juice is worth the squeeze then go for it.  Just don't break it.

 

 

[mrfunex]

The M3 also had a far racier 8400rpm red line... after watching the M3 v ISF v C63 YouTube video, this seemed to be it’s Achilles Heel. At least until they popped it on the track at Silverstone!