Hello, new here to Lextreme. A few FI questions.

[Rock-a-Lex]

Hello, as the title states I am new to the Lextreme forums and have a few questions before I dive into my FI install. Also, I have been a member of the Club Lexus forums for over 7 years.

My car: 2000 Lexus GS400. 134k mi

I acquired a kit from a CL member that dates back to 2003! However it wasn't used much in its first 5 years of its life and wasn't used/installed at all over the past 5 years. It is the SRT stage 3 SC kit (#6 of 20 ever made in varying stages). The kit seems to be in great shape. I cleaned/polished up the SC, brackets, inter cooler and IC piping (got them re-powder coated too).

So, i have the above parts including all couplers, hoses, filter and blow-off valve. I have an Apexi Neo which I'd like to utilize if possible...some say I should just get the AEM FI/C 8. I have 1 step colder NGK Iridium plugs (BKR7EIX-11), 440cc RC injectors w/PnP harnesses and Gates Micro v belt. This kit made 410whp last time it was used; the owner had similar supporting mods as I have but didn't have headers which I have.

Questions:
Are the 440 cc injectors big enough? The last owner didn't have any issues but I'm reading that I should be using 550 cc injectors. The car will be using a pulley that will make around 6.5 - 7.5 psi.

I need a fuel pump, a simple one. Is the Walbro 255 a good choice or should I go with an AEM 320 or an Aeromotive 340? I do not want to have to add relays; I though I dad somewhere that you may have to do this for the Aeromotive. Is this true?

I need gauges. I'm think of an AEM wideband with sensor kit and an AEM low boost boost gauge; I think those 2 should suffice. Are these models good?

Will I need to do a valve body upgrade in the tranny right away or can I just be easy on the car for a while until I am able to do it? I have a B&M supercooler tranny cooler already on the car as well as a PI 3000 stall torque converter with Amsoil ATF. Let me know.

Tuning. Can I really get away with an Apexi Neo for tuning? I really don't want to have to spend more than I have to but still want to do this build right but not overkill either.

I appreciate the help/advice in advance. Thanks!
Nick

 

[Zuffen]

The 440 injectors will handle the power you're looking at.

I'd run the Walbro fuel pump.

Gauges will tell well after you've inflicted damage on the engine if it runs too lean.

The trans will hold together if you take it easy but I would be looking to an upgrade sooner rather than later.

For tuning no Piggy Back will do what you need.

A full stand alone tuned by someone who knows the particular brand on a dyno is the only way to go.

As you speak of 410WHP you're talking close to 500FWHP, or double the stock output.

Although I don't see you getting 410WHP @ even 10psi.

 

[Rock-a-Lex]

Thanks for the reply Zuffen!

As far as power goes this is a custom SC kit so it delivers a lot mor power than say an RMM kit at the same PSI. If you're familiar with old CL member Mr. Johnson, it's his old kit. He posted up his dyno runs a long time ago with this setup and yielded a little over 405whp and 370ish wtq. I think I'll be around these results since I have headers where he didn't. He did NOT have a built tranny and did NOT have a built engine either. This is "if" I have the 7lbs pulley that he put those numbers down with. I cannot tell how many PSI the pulley is that came with the kit.

As far as tuning goes you don't think the AEM FI/C can handle this setup? I know a bunch of people like CL member Speedaddict that is running 397whp on this AEM piggyback.

I really appreciate your response. Thanks!

 

[JBrady]

Hey Rock, surprised it took you so long to wind up over here! Some really sharp performance guys on here for sure.

For those unfamiliar with Rock he has maybe the highest WHP GS400 running a mostly stock set up. By that I mean no FI or nitrous or headwork or cam mods. Stock engine with shorty headers, K&N air filter to throttle body and piggyback tune. 281whp, 209wkW

http://www.clublexus.com/forums/8313697-post2.html

 

[Rock-a-Lex]

Thanks for the warm welcome John! Yeah, took me a little while but I knew I would come aboard

I'm sure I'll learn a lot on these forums in the same way I'd did on Club Lexus. Can't wait to FINALLY start my FI project. Kind of embarrassed to say how long this stuff has been sitting in my basement for. Lol

 

[JBrady]

With the aging of the 1uz/3uz platforms this forum is not too active but there are still many guys here that will show up with some real hands on info.
It will be cool to see you put that SRT supercharger back into service. I wish it was easier to adapt and tune the stock ECU and also strengthen the A650 transmission. Both are roadblocks for making series power with these cars. I still believe the best option is a low boost turbo set up since 400whp is about the top these cars will tolerate for long.

Looking forward to your progress, pics and results!

 

[JustenGT8]

The SRT kit is a nice bit of gear, I hadn't see one before I went looking this morning.

Pretty optimistic power figures though at the boost you have mentioned. There is just no way in the world you will make 400rwhp from 7 psi!! Even if the system was 100% efficient that power defies physics (unless much higher revs are used). It's more like 15psi to achieve 400+ rwhp with most setups....and you'll do that for a few days before your rods cry enough, which is good evidence that old mates figures were a tad inflated

A standalone ECU is clearly the best option and plenty of cheap options these days. Piggy back setup will work but you are asking a lot from such a setup seeing you are also looking to push the hp boundaries.

Keen to see how this develops

 

[Rock-a-Lex]

Agreed but this was a complete custom kit. A lot has to do with the gear ratio inside the SC unit itself...the multiplication of turns on the shaft. Not all kits are created equal. Not looking to beat up my car or constantly race it. I just knew that the kit was rare and jumped on it when it was up for sale without knowing when I was going to install it

Check this out...a dyno posted by Mr Johnson almost 12 yrs ago with this kit. 420whp and 356wtq! Again, this was without headers and all posts I have read from him only mention a 7-7.5lbs pulley...which is the one I think I have too. If the kit makes this much power I may bring it down a little by getting a larger pulley for longevity of my engine and transmission.


http://m.clublexus.com/forums/showthread.php?t=48244&styleid=13

 

[JustenGT8]

Yeah that's a pretty picture but no way in hell was that power made on 8psi.

If that is rwhp ( I suspect it's actually flywheel hp and even then 8psi isn't enough boost), it would take nearly double the boost to make that power. A stock VVTi will make ballpark 200rwhp so clearly to make double that you need double the air, which pretty well means double atmospheric pressure to get it right

We'll set aside the very favourable figures US dynos seem to produce (have to keep the customer happy ) but I'd guess this was done on a dynojet which are well known as reading high.

No question that twinscrew will make the power though, that's a very capable kit. A 15psi pulley and you are sorted. The 440's will just support that power. Your rods won't last though. I reckon your engine will survive 3 400m runs at the drags. Around the street it will be fine if you aren't using the power, but they are not strong rods and a real 400rwhp will break them pretty soon.

 

[Rock-a-Lex]

Totally agree. In any event this thing made real power. The previous owner has a post up where he said that Mo from SRT took him for a ride when it was first installed. Spun the wheels at 60mph on his 285's. I don't really care about the numbers to be honest. I just want it to be a fun weekend vehicle that I can push every once in a while; as mentioned earlier I've owned her for over 10 yrs so she deserves the additional power. I know the car isn't and will never be a sports car; just want it to be fun and should be drastic from how it is today...and it's pretty fun for me as it is right now.

I'll keep you all posted as to my progress. Still unsure about a cost effective standalone though; not sure which one to get.

 

[JustenGT8]

All good. Get the SC installed and keep us posted on the fun result

 

[FoPar]

that's big hp from that boost as suggested even for a turbo car let alone a blown car, what MPH did the car run over the 1/4?

 

[Rock-a-Lex]

Not sure. I don't think the previous owner tracked the car. From what I've read on all supercharged 2nd gen GS's, especially with this kit the tranny becomes the weakest link. Where you have to literally lift your foot off the gas for a split second in order for it to shift to the next gear. With this said I've never read anywhere of a SCd GS running under a 12.7s 1/4 mile. If the tranny was built perhaps it would be a little better at proper power levels of course.

 

[JBrady]

Yeah that's a pretty picture but no way in hell was that power made on 8psi.

If that is rwhp ( I suspect it's actually flywheel hp and even then 8psi isn't enough boost), it would take nearly double the boost to make that power. A stock VVTi will make ballpark 200rwhp so clearly to make double that you need double the air, which pretty well means double atmospheric pressure to get it right

We'll set aside the very favourable figures US dynos seem to produce (have to keep the customer happy ) but I'd guess this was done on a dynojet which are well known as reading high.

No question that twinscrew will make the power though, that's a very capable kit. A 15psi pulley and you are sorted. The 440's will just support that power. Your rods won't last though. I reckon your engine will survive 3 400m runs at the drags. Around the street it will be fine if you aren't using the power, but they are not strong rods and a real 400rwhp will break them pretty soon.

Justen, why do you feel that a stock 1998-2000 GS400 would make only 200whp? The engine is rated 300hp @ 6000rpm 310tq @ 4000rpm. In a 3700 pound car that the factory rated at 5.7 seconds to 60mph. I actually did better than that with my heavier LS400 which has the same engine/trans/diff. Typical dynos give 230-240rwhp which is roughly a 20% loss over flywheel... All very reasonable yes?
Adding headers to the otherwise stock exhaust picks up 15-20whp. Throttle body, air cleaner and mild tune is good for more. Rock's car made the most of any I have seen but lets just say 250whp we really are looking at picking up 60% power with half an atmosphere of boost. Solid yes but not unheard of...

 

[JBrady]

Now... whether it would be a good IDEA or not on the rods and the trans that is another question altogether.

 

[Rock-a-Lex]

Very true. Also, I had my dyno's done on an AWD dynodynamics dyno; it wasn't a dynojet.

A while back I recall looking at a used GS400 for sale that had an RMM supercharger. It did need a serious tune and did not seem to have been maintained at all. The seller liked my car and asked me for a ride. He was astonished on how quick my car was for the mods it had...honestly it didn't "feel" that far off from his supercharged setup. But again, he said his tune was off and mentioned that it was only making about 330whp. Obviously I passed on the car and asked him to part out the supercharger. He didn't want to so I continued my search and about a year later found the kit I have now.

The addition of the steeper gears and 3000 stall converter really wakes the car up; especially off the line.

 

[JustenGT8]

just ballpark figures mate is all.

the best i have seen locally from a very well tuned setup, running excellent headers, a SM4, on a honest dyno, thru a manual was 208rwkw (278rwhp) @ 8000rpm

A totally stock setup thru an auto isn't going to get near that.

real world, i just can't see an SC'd running 400+rwhp from 7psi? even turbo i would be astounded and a turbo isn't taking 50+hp off the crank to be driven.

My SC setup took 17psi to make anything like 400rwhp......admittedly it was a M122 on the non VVTi but this is a real world figure and a long way short of what was postulated here.

Happy to be proven wrong and it would be a cracking result and a testament to Toyota's head development, as that would be the most significant difference.

 

[Rock-a-Lex]

Hey all. I'm the newcomer here and you are the one's that are well versed in this stuff especially when it comes to forced induction. I came here recently to learn from you all and perhaps one day be able to give someone else a bit of advice on this stuff. Bottom line is I think these cars are great and this will be my first FI'd car...pretty excited.

I was really contemplating a year ago ditching my SC setup and simply going with SRTs new twin screw setup but they want a lot of money for it. The crazy thing is they almost pulled off 400whp at 8psi with this unit as well! Not into the look of this kit as it has a very domestic look to it since it's a roots style and all; but it's new. Pretty cool..check it out.

http://www.swiftracing.com/srt/item.aspx?id=169&u=1000169

 

[JBrady]

just ballpark figures mate is all.

the best i have seen locally from a very well tuned setup, running excellent headers, a SM4, on a honest dyno, thru a manual was 208rwkw (278rwhp) @ 8000rpm

A totally stock setup thru an auto isn't going to get near that.

real world, i just can't see an SC'd running 400+rwhp from 7psi? even turbo i would be astounded and a turbo isn't taking 50+hp off the crank to be driven.

My SC setup took 17psi to make anything like 400rwhp......admittedly it was a M122 on the non VVTi but this is a real world figure and a long way short of what was postulated here.

Happy to be proven wrong and it would be a cracking result and a testament to Toyota's head development, as that would be the most significant difference.

Very interesting. Was that a VVTi engine? I would expect more at 8000rpm. I am assuming it had its rods upgraded at least?

Consider that my completely stock 4000+ pound LS400 (1999 4.0 VVTi) went 99mph in the 1/4... the factory rating of 300hp has to be accurate. Heck Errol found 308hp at 6500rpm on 1st gen heads, cams, valves, springs. The VVTi heads have to have at least 20hp over that and probably much more. The VVTi intake should not be a problem.

I think the reports of 250+whp on slightly modified engines are completely reasonable. I do not know how efficient the SRT is but the dynamic compressor SCs tend to be less parasitic than the roots types and with very reasonable adiabatic efficiencies. I realize "estimates" are just that and real world is all that matters but you may agree with me that 7.5psi (0.5 bar) on a well engineered turbo... a reasonable "guess" is 50% gain.

 

[FoPar]

Cams n headwork will make more, we are showing 270rwhp@5500rpm with 11:1, ported heads flowing 290cfm on E85 thru a Powerglide. We see 460-480rwhp@10psi twin turbo with that same combo. Factory heads we needed nearly 20psi to see same power though that was 8:1 CR.

Run the car down the 1/4 after it's done, your MPH will tell u engine hp. I'd be surprised if it's even showing 400hp @ flywheel on 8psi.