View Poll Results: What will be the IS-F final HP number
400-405
8
5.00%
405-410
7
4.38%
410-415
13
8.13%
415-420
25
15.63%
420-425
56
35.00%
Over 425, I was thinking like 600.....
51
31.88%
Voters: 160. You may not vote on this poll
What will be the IS-F hp?
07-21-07, 09:10 PM
#61
Driver School Candidate
Join Date: Mar 2007
Location: CA
Posts: 26
Likes: 0
Received 0 Likes
on
0 Posts
No, most engines will go 2mm over on valve size without any additional bore. Street heads focus on velocity at lower rpm, so the ports tend to be smaller. Making them bigger gives more top end, which is why we port and go oversize on valves, but it also takes away from the streetability because the low port velocity in the bottom end of the rpm scale means less torque until the engine revs up. Hopefully this will be possible to "fix" with increasingly variable valve timing and (hopefully) lift.
The Geneva press release did mention the IS-F tuning focused on intake airflow optimization, but I imagine that is related to the use of an electric driven intake cam. Valvematic in a high rpm performance engine like the IS-F would be a bold stroke if the engineers can pull it off without compromising reliability. It would help close the power gap with the highly touted 6.2L AMG engine. As much as I would like to see Valvematic in the IS-F, I give it little chance of happening until its use in the smaller engines confirms its long-term reliability. I would love to be wrong.
07-21-07, 09:19 PM
#62
Driver School Candidate
Join Date: Mar 2007
Location: CA
Posts: 26
Likes: 0
Received 0 Likes
on
0 Posts
Yes, we haven't seen anything on the heads other than they are high performance. The Geneva press release described the exhaust as a low pressure loss system with a semi dual exhaust manifold which is less restrictive and improves hp and efficiency. Not being a gearhead, I have no idea what a semi dual exhaust manifold is. Maybe it is just a translation error.
07-22-07, 05:38 PM
#63
Guest
Posts: n/a
Okay, I have the foggiest idea what some of you are talking about
but did anyone mention the 5.0 in the LS is detuned....so I am sure the IS-F will get some of its power.I mean the 4.6 makes 380hp.
A 5.0 making 400hp is only a 20hp gain with .4 liters more of displacement. Lexus engines are never high strung. They can ALWAYS make more power.
However, since this is a "F" car, shouldn't it not make the MOST power this engine could make? Or will Lexus keep the power around 420 or so as it remains reliable.
If the IS-F is as reliable as the average Lexus, that would totally different than anything this market has seen. Similar to the NSX as a reliable super car.
07-23-07, 03:18 PM
#64
Driver School Candidate
Join Date: Mar 2007
Location: CA
Posts: 26
Likes: 0
Received 0 Likes
on
0 Posts
.....However, since this is a "F" car, shouldn't it not make the MOST power this engine could make? Or will Lexus keep the power around 420 or so as it remains reliable.
If the IS-F is as reliable as the average Lexus, that would totally different than anything this market has seen. Similar to the NSX as a reliable super car.
OK SICK I will bite
....Reliability sells Camrys, hp sells performance cars, that's marketing. However, the IS-F is not intended to big a big profit maker, but rather a performance image maker that puts Lexus in league with the Germans. Toyota wants to establish their European market and what better way to do so than go toe to toe with the biggest bullies in the hood, M, AMG and RS. They may get there nose bloodied first time out, but if they can fight to a draw they will have gained the type of respect no amount of marketing can garner. You don't bring a knife to a gun fight, they need the ponies.Performance with reliability is a noteworthy goal, but a reputation for reliability takes years to establish while performance will be know immediately. Having said that, I think Lexus is capable of getting mucho hp out of 5 liters WITHOUT compromising reliability. They are starting with a base engine block designed to the highest reliability specs because of its intended use in their flagship model. Throw in engine oil and transmission fluid coolers, a high-flow oil pump, large lower intake and a modest 7,000 rpm redline and I think 430+ hp with reliability is attainable. I like that the car was designed with track reliability in mind because it should be super reliable in street use.
I am hoping for 430+, but if your 420 prediction does turn out to be correct, I will cry the entire trip down to pick up my shiny new red F shod in dark gunmetal rims.
07-30-07, 08:17 PM
#65
Rookie
Join Date: Mar 2007
Location: nj
Posts: 54
Likes: 0
Received 0 Likes
on
0 Posts
i am guessin 430 too bcuz the 250 and 350 hav a 1 liter 100 hp difference so wit the 4.6 liter bein upgrade to 5 that looks like a 50hp increase makin the is-f hav about 430hp throw n all those coolers and the intake and 430+ is mos definitely attainable... i kno im comparin v6s against v8s but it stil does make sense
08-07-07, 11:38 AM
#66
Lexus Champion
Join Date: Dec 2006
Location: NY
Posts: 3,370
Likes: 0
Received 0 Likes
on
0 Posts
Hey, I just found that the UZ engines can rev pretty high. However, of more interest, is that there is a stroker kit for the 4.0 (to 5.4 and 5.7L) That will rev to 8000-8500rpm. That is pretty damn good IMHO. I didn't bother to check the cylinder dimensions of the UR in comparison to the UZ series, but I don't think Lexus would have made the newer engines any less rev-able, would they?
Last edited by MR_F1; 08-07-07 at 11:43 AM.
08-07-07, 01:19 PM
#67
Lexus Fanatic
Join Date: Jan 2005
Location: A better place
Posts: 7,285
Likes: 0
Received 0 Likes
on
0 Posts
Hey, I just found that the UZ engines can rev pretty high. However, of more interest, is that there is a stroker kit for the 4.0 (to 5.4 and 5.7L) That will rev to 8000-8500rpm. That is pretty damn good IMHO. I didn't bother to check the cylinder dimensions of the UR in comparison to the UZ series, but I don't think Lexus would have made the newer engines any less rev-able, would they?
The UR engine was developed in parallel with Toyota's F1 V10 and I am extremely confident it was designed to rev more freely and rev higher than the UZ. In the coming years we will see the true potential of the UR.
08-08-07, 12:03 AM
#68
Driver School Candidate
Join Date: Jun 2005
Location: BC
Posts: 19
Likes: 0
Received 0 Likes
on
0 Posts
407 hp 350 lb-ft torque
08-08-07, 12:23 AM
#69
Lexus Fanatic
Join Date: Jan 2005
Location: A better place
Posts: 7,285
Likes: 0
Received 0 Likes
on
0 Posts
.
08-08-07, 07:48 PM
#70
Tech Info Resource
iTrader: (2)
Hey, I just found that the UZ engines can rev pretty high. However, of more interest, is that there is a stroker kit for the 4.0 (to 5.4 and 5.7L) That will rev to 8000-8500rpm. That is pretty damn good IMHO. I didn't bother to check the cylinder dimensions of the UR in comparison to the UZ series, but I don't think Lexus would have made the newer engines any less rev-able, would they?
Stroke is the enemy of high rpm. Always.
Last edited by lobuxracer; 08-08-07 at 07:56 PM.
08-08-07, 09:30 PM
#71
Driver
Join Date: Jul 2007
Location: MD
Posts: 146
Likes: 0
Received 0 Likes
on
0 Posts
No official numbers have been released by Lexus, so that site is speculating just like everyone else. I believe that Lexus will provide the horsepower information for the IS-F at a press release some time before the end of this month.
08-08-07, 10:30 PM
#72
Lexus Champion
Join Date: Dec 2006
Location: NY
Posts: 3,370
Likes: 0
Received 0 Likes
on
0 Posts
I know people revving 2JZ's to 12k rpm. It doesn't mean it's prudent for a street engine. Service life for a racing engine is basically one race weekend, sometimes even less. Just because you CAN spin it to 8000 rpm doesn't mean it's prudent. It also means Toyco isn't going to release it for public consumption with a redline that high. They have an unofficial maximum 20 meters/sec mean piston speed limit for their engines. The 2GR doesn't even spin that high. 20 meters/sec is still the standard for reliability and longevity, and the 2GR doesn't even go to that in stock form.
Stroke is the enemy of high rpm. Always.
Stroke is the enemy of high rpm. Always.
08-16-07, 12:35 PM
#75
EV ftw!!!
All of you guys are so off in your guesses and predictions! 
It will put out 500 HP and 495 lb-ft of torque!
It will put out 500 HP and 495 lb-ft of torque!