La400

Here is the dyno results on a 1998 GS400, right at 100,000 miles:
Cold Air Intake / ECU
Rest bone stock

Rear Wheel
Max Power = 243.3 HP @ 5,200 rpm to 5,250 appox, peaked and dropped off quickly
Max Torque = 259.9 TQ @ 4,000 rpm to 4,200 approx, peak torque started about 3,500 rpms and dropped off quickly after 4,200 approx

HP and TQ intersected at about 5,250 at approx 233 HP/TQ

Ran 8 trials, some screwed up, down shifting took place, torque shot up to 272. Cool down times were included.

Anyway, we tested the extra pwr mod and there was no difference in reading. Wide open makes this mod not as effective as when just driving around.

Now for the heads, hope to be back soon with results.

Best to all

lex400pshR

Nice!
what intake and ECU? SRT?

rominl

iTrader: (4)

that's pretty good numbers for intake man, i think it's on the high side of what i see so far.

La400

I am running a complete Akimoto Hi Flow system. The only difference maybe when I did the timing belt, initial timing was set at 12 degrees, factory calls for 10 - 12 degrees.

Never had the hood open and seen engine rev up to rev limiter shut down, 6,300 on the money. Everyone there was quite impressed with these little engines that can.

Interesting too is that at 5,000 rpms, something in the systems dropped both TQ and HP, only couple drop in each, but happend at the exact same rpms. Pick immediately back up but then TQ dropped off a lot and HP started climbing.

TQ started dropping off after 4,300 rpms all the way to 6,300, whereas the HP has a steady climb to 6,300 with only the slight dip at 5.

Hope this is helpful.
Best

JBrady

Horsepower and torque are always interactive because power is torque times RPM / 5252. So, HP and TQ will always be the same at 5252rpm. Peak torque occurs at maximum cylinder efficiency which in the case of the VVTi 1UZFE is around 4000rpm. This is almost always the peak volumetric efficiency as well.

Power will continue to climb even though the torque reading is dropping until the drop ratio equals the rpm increase at which point the power will peak and again, on these engines should be around 6000rpm. You show below the peak power happening at 5200-5250rpm but then give a different output for that same RPM you also say the power increased steadily to 6000+rpm.

Power will always start low and increase whereas torque starts fairly high and goes up at mid rpm and then drops at higher rpm (unless turbocharged, supercharged, nitroused or very large cam and manifolding)

One way to think about power and torque would be to think of your engine as if it were a hammer. You swing the hammer once and strike a blow. How much force that hammer blow produces is your torque (force). Now, power is how MANY times you swing the hammer. One swing of a 10 pound hammer is less TOTAL force than 2 swings of an 8 pound hammer even though the 10 pound hammer had a higher PEAK force. Total force is your power. So force (torque) times the frequency (RPMs) equals power (horsepower).

La400

Hi jbrady,
From my graphs it shows the HP kinda leveling off starting at close to 5,550, meaning within 2 -3hp at peak of 243.3 and maintaining this till shut down of 6,300 rpm.
Hope this clears it up for you.
Best

JBrady

Yes, this is more or less what I see from my GTech Pro Competition dyno graphs. Peak power is usually around 5600rpm but has been as high as 6000rpm.

BTW, on my 14.22 pass I had the GTech installed (the pass was actually at the HRP racetrack in Baytown but ran the GTech as a comparision) and recorded a peak of 223rwhp @ 6025rpm. My all time highest readings came last month with a 235.7rwhp@ 5658rpm and 243.9rwtq @ 4768rpm. The GTech only records the dyno for the gear in which peak power is reached so the 4768rpm is actually the RPM that the engine dropped to changing from second to third gear. I believe that the torque at lower RPMs is even higher based on the shape of the dyno graph.

Here is a screen shot (best I could take) of the GTech PASS software dyno graph

GILLEXUS

iTrader: (14)

La400,

Does Akimoto Hi Flow system have an ECU w/ it or did you use an SRT one

La400

It is their ECU, actually came with car when purchased, had a hard time finding it listed out there. Does not seem to be the most popular. Jap brand.

GILLEXUS

iTrader: (14)

I could not find any info. on it either..Is it a module like SRT that wires into your Stock ECU?

La400

It comes as a package, if I remember, 260-300$. It is the tunnel cone. In research I found some testing of a number of different brands and this seems to produce more to the claims. When you get into it, it sounds like an old fashion 4B Rochester Carb. Sucks some air. I dont know if the other brands do that or not.

La400

Just remembered, I found the set up by following research on the Akimoto Hi Flow System for GS300. Originally I thought someone had stuck a GS300 intake on this GS400, until I discovered the GS400 setup. I will take pic of this one and paste.

GILLEXUS

iTrader: (14)

I hear the SRT is kind of loud at WOT. It seems to abit louder than the others I hear. Have any pics. of your ECU. just curious? wonder how big it is or how many wires actually connect to the ECU.

La400

wiring on Akimoto

La400

Akimoto layout