booja

iTrader: (1)

it should not be at 260whp... if its rated at 290hp even taking a 15% loss it would make it 246whp. being an auto there is more loss so it should be about 20%... at 20% loss it should make about 232whp

ScottURnot

iTrader: (33)

Numbers look good, my 97 did 230-235rwhp (cant remember exact)
mods were full exhaust, headers and BFI otherwise all stock.

5sp_jzz30

iTrader: (2)

damn i never realized V8 were such weak sauce.

so crank it is rates at 290. 30% drivetrain loss seems ridiculously high even for an auto. even given that 200ish whp stock? des this seem to be right.

so from headers, full exhaust, and bfi you only got 35hp?

you can make 235whp on a 2jz all day even NA. granted it will need more then a header and full exhaust but at the price of headers and an exhaust it can be done.

ill stick to my six

ScottURnot

iTrader: (33)

Well, 235 RWHP but 263 torque, Not bad for stock NA with exhaust. Whats the torque on a NA six?

RedPhoenix

iTrader: (10)

Its not all about peak number man, you know that lol. and who cares about HP? its all about the torque.

My 92 1uzfe puts out 200ft tq AT 2600 rpms...and stays above 200 ft tq until 5400 rpms and that was with the auto, I wish I could find my dyno of it when it became manual... ill still be looking. Confirmed by 2 dyno's to be pretty within spec of eachother.

However I agree the 1uzfe is rated badly... and I really think the engine could have been tweaked a little bit more from factory for better power output. But people who get serious into the 1uz can easily get high numbers out. Comparing it to the JZ engines I think is not right because the JZ engines have been tinkered with by how many more people than the UZ family? From factory it was turbo'd, making it a better candidate to experiment with than the UZ series, which is cramped into the engine bay with little room to get any turbo in there, making it not a prime candidate for tinkering with (compared to the JZ family). Apples to oranges I believe.

My reasoning for the 1uz over the 2jz was simply the fact that every moron that talks to me about my car always ask's if its a "2j". And I can politely think to myself how ignorant they are... such as 240sx guys with KA-T's and everybody thinks they have a SR20. There are OTHER options out there!



I bet if the OP slapped a SAFC2 or whatever on there and tuned it, he would pick up another good chunk of power. Think about that Durrby! Looking at the tiny graph on youtube, looks like your AFR dips below the "line" (assuming its 12:1 AFR) in upper rpms, there is some lost power there. Your graph looks really good though, power just keeps on going (guess thats the point of the VVTI kicking in).

SHOLEXMAN

^^^The dyno graph at the end doesn't do any justice to small lol.

Durrby

iTrader: (3)

lol I linked it to the video info...but here it is a little larger/clearer.

Speed


Engine speed

GS FONZy

iTrader: (6)

Your car is rated with lower HP/TQ then the VVT version.

1uz GS' are putting down that power in stock form, something does not seem right.

Da Coupe

iTrader: (7)

Numbers seem very low. What headers are you running and what's your exhaust specs? This would also gain more interest in the Performance Section.

JBrady

Looks like he has the IMF headers.

Before jumping to any conclusions I checked for earlier posts. Looks like he had to have the stock exhaust modified to fit. Most exhaust shops build parts to fit... NOT to make power. I would like to see some pictures of that work. That could be part of the problem.

Also, there is a range of power these engines can make. Make sure sensors and things like spark plugs are up to the task. Make certain to use quality gasoline with the highest octane available (93 in Houston, 91 or lower in other areas)

That said this dyno seems low. Attached is another members stock 1998 SC400 (identical car) that dyno 234.5rwhp and 264.9rwtq. The stock SC4xx manifolds are very restrictive so I have to believe any header is going to be better. We should also keep in mind that dynos vary, conditions vary, vehicles naturally vary. A base dyno would have been nice. IMO it is unfortunate that he had to delete his cats.

https://www.clublexus.com/forums/5047305-post20.html

https://www.clublexus.com/forums/5047318-post31.html

v8soarer91

All should remember a dyno is a TUNING TOOL.

"DURRY"
The AFR are wrong for a car with just exhausts done.

the standard ecu can tune the afr all the way down to the 9's. do you have a piggyback/ecu to be able to adjust the afr as flat as what is in the graph??

very very lean when you hit the loud pedal !!!!

there is no converter lockup dip at around 4500-5000rpm ???

Durrby

iTrader: (3)

it's in the beginning of the vid. imf headers from the group buy. 2.25" piping from the headers back, x-pipe in the middle 5zigen fireball mega mufflers. all cats/resonators deleted.
Here you can see where they cut, turned and rewelded the stock flange



Plugs are brand new done at lexus about 2k miles ago. Can't say for sure about the senors. 93 octane used since I bought the car back in may '09
everything outside whats listed is bone stock.

JBrady

Something is not right here. I do not want anyone to jump to any conclusions and do not take my post to be a negative on the headers.

That said there are 3 things changed on this application. Headers, cats
removed, stock Y pipe modified.

I have posted many times I do not recommend removing the cats or
modifying the stock Y pipe. The Y pipe mods I am talking about are NOT the
flange rotation. That work from the picture looks fine. It is removing the Y
section and replacing with an aftermarket X, H or Y that I do not
recommend. The factory design looks restrictive but is very effective at
these power levels. I can not say that this particular mod that is pictured
above is a negative but rather the stock part works well and until a proven
option is available I will continue to recommend staying stock here. The
only Y pipe mod I currently recommend is replacing the stock 60mm center
pipe and resonator with a 2.5" pipe and straight through resonator in the stock location.
If you do this KEEP the actual Y section and 1/2" or so of the 60mm pipe and
slide the 2.5" over that.

Next is the removing of the stock cats. The stock cats are a very high flow
metal substrate design. In addition to not creating much restriction to flow
at peak flow they actually work as a one way valve to enhance low RPM
torque. Keep the cats. I understand that the IMF headers require removing
or relocating the cats and at this point you have removed them. I honestly
do not know what difference would be created if you had them re-installed
under the car but that is what I would have tried if I were using those headers.

Again, do not take my next words as a slam on the IMF headers. The design
is based on a bolt in for a stock 92-95 SC400 when you remove the cats.
The length of the tubes and the collectors is determined by fit not any
actual tuning. The same can be said for the other headers on the market
but each design is different and will give different results. With the cats
removed and the large collector volume squeezed up to the small Y pipe
tubes there may be a reversion problem going on.

Regardless your low and mid range torque is WAY down. Take a look at the
stock dyno above at 4000rpm vs your dyno at 4000rpm. Stock peak torque
is at 4000rpm and the dyno above starts at just barely that.

RPM---STOCK---Durrby---difference
4000---255---224--- 31 less
4200---260+--227--- 33 less
4400---255---224--- 31 less
4600---245---225--- 20 less
4800---235---226--- 9 less
5000---232---226--- 6 less
5200---230---224--- 6 less
5400---224---222--- 2 less
5600---222---222--- same
5800---212---212--- same
6000---200---no D-- looks about the same

The stock peak power is supposed to be at 6000rpm but the stock dyno
above peaks at around 5700rpm and the Durrby chart at closer to 6000rpm
although not ran on the dyno. So, the stock dyno is MUCH stronger up to
4600rpm and then slightly below until near peak. 30+ foot pounds of torque
is more than vehicle to vehicle variance or dyno differences. There is a
reason the Durrby dyno is way down on torque. The reason is NOT too little
backpressure... if in fact the reason is the exhaust (we don't know this for a
fact) then the lower dyno is due to more backpressure AT THE VALVES and
this would be due to flow dynamic differences IF that is in fact the problem.

Now, for peak power this car could have been down 10-15hp over the stock
dyno BEFORE the headers. If that were the case the headers COULD have
added 10-15hp but this is only conjecture since we do not have a baseline.
We also do NOT know if the headers have anything to do with the torque
issue. Hopefully someone will do a before and after baseline if they decide
to run these headers. Again, I do not recommend deleting the cats and at
this time there is only one header choice that allows that and even then still
requires modification for an SC400 install.

Rattletale

Only 235 hp?? From a 4.0 V8? Now i feel a little better about the 250 hp my 3.0 V6 makes in my GS300 awd.

spdrcr771

iTrader: (21)

Ok here is mine. 98SC400 (HP MODS) 2.25 Mandrel bent cat back w/x pipe true dual. SRT performance intake & 3.76 TT LSD rearend. This is my base line, cause im fixin to order the S & S tri Y headers, oh and i bought the car 3yrs ago w/83000 it now has 172000 on it and ive never changed the spark plugs, gonna get the Torque Masters.
might be hard to see, need to make better copy.