Performance Enhancements...

[SteveAvery]

I'd like to improve the acceleration without over-stressing any parts or breaking the bank, and should appreciate any advice, please.

[is200 Newbie]

Change the stock air filter to an oiled K&N one. Around £30 and will last the life of the car. You will notice a difference in acceleration, not major but noticeable.

[john leeds]

I enquired at a performance centre once and it was told it would be hard to improve what I had without spending thousands, they said the japs built it that way on purpose.

[Neil E]

I'd be interested to see some dyno/acceleration figures to back that up. I am aware that some of the guys in the states (and one or two in the UK) have experimented with cold air intakes.

The car produces around 280 bhp and with a good launch, should reach 60 mph in 6 seconds or slightly less. It's possible to improve throttle response and slightly quicker shift changes but apart from taking some radical measures to save weight, noticeable or significant gains will require serious effort, expertise and expenditure. I could suggest likely costs but it makes me wince. :)

[aviator888]

Change the stock air filter to an oiled K&N one. Around £30 and will last the life of the car. You will notice a difference in acceleration, not major but noticeable.

I am sorry but i disagree with that. Unless the current air filter is clogged up simply changing to K&N filter does not make any difference in acceleration.

They make good quality filters however i will pass on their "washable performance oil filters" range and treat their air filters as normal- whent it's time for service the old filter ends up in the bin!

It is possible to gain few horsepowers by fiddling with intake, but that involves reprogramming ECU and the difference in the performance will still be barely noticeable. There is no cheap solutions im afraid :)

[Neil E]

Hi Mel

I'm not aware that anyone has developed a mod for the original ECU other than a replacement/piggy back. I agree a £30 filter on its own will do nothing to improve the performance over a clean standard paper filter but in principal, a good hi flow, cold air intake might gain a tiny increase.

It's all perception but a less restrictive custom exhaust made my SC 'feel' more powerful and quicker to pick up in the mid-range but the dyno confirmed what I expected to see, max power 280.9 bhp. I think Lexus say it's 279 standard for the later car and 282 for the earlier one so I was very happy to see that figure from an engine with 101k on it.

To put some rough numbers to John's post. The race tuning company that did the dyno test offered me a twin turbo solution with ECU and a tried and tested map for £10k but I think if you factor in everything that an SC is going to need to cope with 600 bhp, £15k is more realistic. Clearly you wouldn't run it at 600 all the time but it would turn a refined cabriolet into a fire breathing monster. I've seen a 5.0 litre supercharged Soarer in the flesh and the experts had no end of trouble trying to tune that to work properly. Toms do a complete supercharger kit, I think it's around £8k but that's just the start.

It all sounds very expensive but if you have those kinds of funds to do track days or trips to the Nurburgring and can't quite afford to get on to the waiting list for an LFA, it's a cheap and exciting alternative.

[alphacat]

_{I agree air filters make little difference if you keep them clean. K&N make a living out of cognitive dissonance.}

_{I have seen an SC 430 in the states fitted with a twin turbo charger (Garret I think) cost about £3800 and that was then gave the car 400+ bhp.}

_{I am surprised anyone wants more acceleration as I am sure mine is still well under 6 secs even now. I have a theory that the car was built at 282bhp as that was an agreed limit in Japan and its known that many manufacturers didn't stick to it. In a little run against my son in a 335 BMW estate chipped to 340 bhp my l 430Sc was in front.}

_{lets face it to get under 5.5 sec's you usually need about 320 bhp minimum (in a saloon car and the SC being a convertible is on the heavy side. My S4 was pulling 341bhp and 0-60 was at 5.4 secs. not a lot in it.}

_{The 430 SC will do 80mph at 2000 revs not a lot will touch that. Its is limited for top speed(some say 149 mph) partly by the very long legged 6th gear but also by electronics. I don't think its safe over 150mph. Its not a sports car. Its a long distance cruiser without the ability to carry much luggage.}

_{If you want any meaningful performance enhancements stiffening and shocks should do the trick.}

[aviator888]

Hi Mel

I'm not aware that anyone has developed a mod for the original ECU other than a replacement/piggy back. I agree a £30 filter on its own will do nothing to improve the performance over a clean standard paper filter but in principal, a good hi flow, cold air intake might gain a tiny increase.

It's all perception but a less restrictive custom exhaust made my SC 'feel' more powerful and quicker to pick up in the mid-range but the dyno confirmed what I expected to see, max power 280.9 bhp. I think Lexus say it's 279 standard for the later car and 282 for the earlier one so I was very happy to see that figure from an engine with 101k on it.

To put some rough numbers to John's post. The race tuning company that did the dyno test offered me a twin turbo solution with ECU and a tried and tested map for £10k but I think if you factor in everything that an SC is going to need to cope with 600 bhp, £15k is more realistic. Clearly you wouldn't run it at 600 all the time but it would turn a refined cabriolet into a fire breathing monster. I've seen a 5.0 litre supercharged Soarer in the flesh and the experts had no end of trouble trying to tune that to work properly. Toms do a complete supercharger kit, I think it's around £8k but that's just the start.

It all sounds very expensive but if you have those kinds of funds to do track days or trips to the Nurburgring and can't quite afford to get on to the waiting list for an LFA, it's a cheap and exciting alternative.

Neil Your SC430 goes faster than a speeding bullet. Feeding the beast with 600hp may take away some of it's character and appeal. Looks like 1UR-FSE engine off LS/GS 460 would hit the spot (extra 100+ hp and a lot more torque) shame Lexus never considered fitting this marvel to SC..

The more time i spend in this SC part of the forum, the more i want one

[SteveAvery]

Thanks for all this info. After reading it all, I've done some investigation. As a non-auto-engineer, I'm a bit out of my depth, but It seems that there are three things that could be done without uprating the engine itself:

1. SRT (Swift Racing Technologies) cold air induction system with heat shield and chip. + 15-20 bhp.

2. Custom-built outlet manifolds and a performance exhaust system, minus a catalytic converter or two. + 20-40 bhp.

3. Higher stall speed torque converter. This would launch the car MUCH faster and provide faster downshifts and gear changes.

I'd appreciate comments on these three options, please.

[Neil E]

Steve, from the little I have read in the past, SRT build high performance engines at great expense so if they claim an increase of 15 to 20 bhp with a cold air intake and a chip that's worth investigating.

Improved exhaust flow by custom built headers or exhaust manifolds via 2 sports cats and a custom exhaust should make a noticeable difference, It's custom fabrication work so it won't be cheap. There were a batch of headers made in the states at reasonable cost but I believe some suffered cracks after a short while. You can't delete the cats if the car is to remain road legal but it's okay for the track. I'd say that's probably going to cost £2.5K +

Swapping the torque converter to get off the line quicker, faster shifting, etc and we're really getting into competition territory now. There is a gearbox adjustment setting for faster changes, I think it can be adjusted on both the earlier and later models with the sump removed, I would need to do a search to check but that would be a cost effective improvement.

Add Peter's sensible, essential, improved suspension, so coil-overs, stiffer anti roll bars, then consider wider wheels and tyres to grip the tarmac, a big brake upgrade kit and you are on the slippery slope to spending a lot of money for fractions of seconds saved.

Mel

I like your thinking on the 460. Perhaps the ISF set up may be the way to go. I would love to do something like that to a Soarer.

And yes you and Peter make the point well, the SC is capable of going quite quickly in standard form.

[SteveAvery]

Your comments are encouraging, Neil. Thank you very much.

I'll go for the SRT induction system and a performance exhaust system to start with.

I'm glad that you pointed out that removing a cat is not allowed, because I have heard suggestions to remove them. In that case I'll just replace them with sports cats, as you suggest. Any recommendations? For track days, I could have a console switch installed to open a valve so that the exhaust escapes through a hole in front of the rear cats, à la 'Fast 'n' Loud'. Do you like this idea?

As you think that the gearbox adjustment setting for faster changes would be a cost-effective improvement, I'll consider that also, once you've completed your checks on it. How would that affect the ECT switch, which itself provides quicker throttle response and holds each gear longer than when it is switched off? Would that continue to function in the same way, but with even quicker response, or would it be rendered irrelevant?

I'll pass on the torque converter. It sounds a bit OTT.

My wheels are in awful condition; so, I need to renew them, anyway. I've been told that increasing the diameter upsets the speedo and odo; so, that's a no-no. But I would like to have wider wheels and tyres. How wide can they be, without fouling the wheel arches?

I think that coil-overs and shocks will take the mods beyond what I can afford. So, induction, exhaust, gearbox adjustment (perhaps) and wheels will be my limit. If these can get my car to 60 mph in about 5 secs, I'll be happy.

[CraigIson]

NA Engines are harder to get extra power from compared to turbo'd lumps (Which pretty much need more fuel and the boot turning up most of the time) But getting more torque ... that fairly easy!

The question you have about the ECT switch, It would still work in the same way, but the gear shifts would be even quicker when activated. Think of it as, A better torque converter would make it feel like its in super ECT mode when activated, but when in auto mode, The only thing that will change is the RPM it launches at. It will still drive like a Lexus around town :)

The Intake system is restrictive (Not by much but a little) But a little bit of restriction is good. But a different feed into the air box would help.

Exhaust manifolds can defiantly be improved on, It wouldn't cost the earth to have equal length headers made. De-cats are a must if you want more power. and a free flowing X pipe system would be your best option. (But decays are illegal, so sport cats are your only option)

A good remap will free up about 10-15hp. And maybe make it slightly better on fuel.

... IF you wanted to go all out ... High compression pistons, increasing the displacement to 4.4/5L, light weight crank. Throttle bodies and Massively aggressive cams would take it to 500hp (Oh and don't forget the race fuel) As that is what is done to the 3uzfe fitted in the GT500 SC430's

Ive heard a mustang supercharger fits straight on, Then it just a case of mapping ... Might be something to look into

Turbo kits, More of a ball ache but still do able.

However, If you want more power Which ever option you go for, You might want to mortgage your house! as once you start, You can't stop!

[SteveAvery]

Very good info, Craig. Thanks.

I've decided against a torque converter, and await Neil's results of his check into the gearbox adjustment settings that he mentioned above. I assume that your comments about the behaviour of the ECT with the torque converter applies equally to the "gearbox adjustment settings" referred to.

Thanks for the tip about equal-length headers. I'd have had no inkling of this without your advice.

A "good remap" sounds great: More power without using more fuel! It beats me why this isn't standard. I hope that I can find someone to do this who knows what he's doing and doesn't screw it up. How about my local Lexus service centre? They should know how to do it, shouldn't they?

[CraigIson]

For a re-map you will need to go to a specialist (I used a place called Dynodaze/H-tec Elite in Leicestershire for my remapping needs). A lexus service centre won't have the equipment (Or interest!) to do it. (As it will require access to a rolling road and the software to do it). Usually looking around £300-£500 for a decent remap. I would stay away from 'Performance chips'. You can't really beat a good remap tailored to your individual needs and engine.

Equal length headers would need to be custom made, as neil stated earlier, The "Yanky Doodle Doo' Headers that was made and available through eBay might have well been made from butter! people have had no end of trouble with them. But when they work, They make a considerable difference to the way power is delivered ... also sound amazing!

I've actually had a go with adjusting the "Gearbox Ferosity Settings" Which Neil stated. It does make a difference but all it seamed to do was make gear changes a bit more ... noticeable/jerky at lower speeds. it kinda engaged gears a bit more positive instead of being smooth, Didn't notice any difference when you have your toe down.

[SteveAvery]

Great advice again. Thanks, Craig. You're a gem!

[ColinBarber]

Change the stock air filter to an oiled K&N one. Around £30 and will last the life of the car. You will notice a difference in acceleration, not major but noticeable.

you may notice a slight change in noise but no performance increase. The stock intake and filter is good on the GS430/SC430, changing it without altering the mapping won't have any meaningful performance increase.

The SRT intake combined with a catback exhaust is a good place to start - although the European ECU is mapped differently to the US so may not work quite as expected.

[Neil E]

Okay, I'm trying not to get too excited but I have read that the later 6 speed box does have the dial/adjustable valve that permits the quicker shift setting but I haven't seen anything conclusive yet. By that I mean I haven't found anyone to confirm they have actually done it and it works. That may change when I get time in Feb/March. It's definitely been widely tried by the US SC and GS community with the earlier transmission and reports appear to be very favourable.

I agree with Craig's views however I'm not aware that the original ecu can be re-mapped. Aftermarket ECUs are not cheap and though there is plenty of knowledge on Supras and the like, our cars are rarely seen on a dyno so whilst there may be tried and tested maps for various forced induction solutions, don't expect it to be easy to produce a good map for any scenario.

There are a few already but it would be great to see some more UK cars getting 'the treatment. I would urge that before anyone gets too carried away, it's best to determine what you want from the car in the end, absorb all the knowledge that's out there, then form a clear plan with an end goal that suits your needs. I dare say just like Craig's in fact.

Read the threads and the views of the owners that have blazed the trail. If straight line acceleration is the only aim, that's fine for the quarter mile shoot out but if you want to be quick on a circuit then handling is perhaps the first place to start.

[SteveAvery]

Sound advice, indeed, Neil. Thank you.

I'm happy with the handling as it is. I want only increased acceleration in a straight line, with a bit of noise.

I got the cold air induction idea, because I always notice that my car is considerably quicker off the mark when the engine is cold. I discovered that this occurs because cold air is denser, with more oxygen..Therefore I am hoping that, with the SRT system installed, I'll be able to get the same effect all the time. But perhaps this layman's logic is too simplistic... We shall see.

I'll look into re-mapping after the induction and exhaust systems are installed. Perhaps they'll be enough for me.

I do love this car. It's the best I've ever owned, by far. I am serious about giving it "the treatment". In fact, I am awaiting delivery of a very attractive body kit as the first step.

[Neil E]

Very interesting, do tell us more about the kit, I'm trying to finish a big rear spoiler at the moment and it's a real pain. (My skills with fibreglass are quite limited)

There's quite a lot of good info about cold air intakes, apart from SRT there are other suppliers including at least one in the UK that make them specifically for the SC. I haven't seen anyone install a mini freezer ahead of the air box yet but no doubt someone has tried. I do remember fellow Soarer guys testing all manner of filters and intakes but couldn't get a better flow than with the original clean filter. 10 years ago someone also told me that replacing the filter with fine silk stockings was the definitive answer.

Oh, I forgot to say, alloys can be re-furbed for around £65 a wheel or you can go for very wide wheels and tyres. Just do a search and you will find excellent charts with recommended sizes and offsets.I have 285 30 19 Continental on 9.5 inch rims on the back of mine (with correct rolling circumference) and there's still room in the arches.

[ColinBarber]

I got the cold air induction idea, because I always notice that my car is considerably quicker off the mark when the engine is cold. I discovered that this occurs because cold air is denser, with more oxygen..Therefore I am hoping that, with the SRT system installed, I'll be able to get the same effect all the time. But perhaps this layman's logic is too simplistic... We shall see.

The standard intake doesn't heat the air passing through it that much.

The SRT intake works well because it is removing some of the restriction and it is altering the fuelling with a piggyback ECU. Even so they probably dyno better than in real life as once the the bonnet goes down the airflow is slightly restricted again.

[john leeds]

Seriously guys this is getting to complicated, what's wrong with the way it was designed, if all you want is a quick track car why didn't you buy a track car, I believe you can over think these issues to the point of ocd, and there are very few cars to beat the sc and all the time and effort for maybe 1 second doesn't sound good sense to me, but am I missing the point of why you feel the need to do all these alterations. Best regards john

[SteveAvery]

Thanks for the info and advice, guys. I'll try to track down that UK company that makes intakes for the SC430, and compare it to SRT's. 9.5" wheels sound good to me. I'll look for some.

Neil: The kit I've ordered does not include a rear spoiler, I'm afraid, but only front, rear and side skirts. I've just had bad news about it, though. I bought it from Poland, because it was £300 cheaper than anywhere else. They said that they'd send me shipping details on Monday 05 Jan, but, when I reminded them yesterday, I got an out-of-office message saying that they'd gone on holiday on Sunday 04 Jan for two months! £500 goes a long way in Poland, and I suspect that they have, too.

John: Sorry if this thread upsets you, but I am getting much valuable info from it. I don't want a track car per se. (Indeed, I wish to sell my other car, which is too powerful for me now in my dotage: replicars.co.uk ) I just want a little more "oomf" from my smooth, luxurious SC430, so that it acts and sounds a bit like the body kit suggests (if I ever get it).

[Neil E]

Well good luck with the kit. Have you got someone lined up to fit it or are you doing it yourself?

Does it look something like this perhaps?

[Neil E]

Yes John it's important to appreciate what you have in the first place, we are attempting to provide the answers to the question you asked the service centre that rightly told you it would cost thousands. I completely agree with what you are saying, the SC is quick already and it will cost a small fortune to make it that little bit quicker.

I've seen many a good car ruined by modification and then abandoned or stuck in a garage waiting for enough cash to be saved up to get it running at the next level. If you think this is beginning to go in a little too deep you would love some of the other forums I visit and visited in the past. It can easily become an obsession. My motivation for tweaking the SC comes from selling both Soarers a few years ago. When I did so I said I would find time a little later to have a go at an SC430 so here I am 6 months in to it.

Steve, I think your Polish kit supplier will come through okay.

[SteveAvery]

Yes, Neil, that's exactly the kit I bought. I think that it's the best-looking one on the market. It makes your car look great. No, I'd make a complete mess of it, if I were to attempt to fit it myself. There's a local body repair shop here where even supercar owners take their cars, because they are so good at what they do. Fortunately, the owner is a buddy of mine.

I'm guessing that you fitted yours yourself. It looks like a perfect job from your photos. Can you tell me where you had any problems with its fitting?

I'm particularly concerned about difficulties re-fitting the headlamp washers and the front and rear parking sensors. Was that hard to do?

I've spent ages scouring the Web for LED reversing lights small enough to fit into those little holes, but you seem to have managed it. Where did you get them, please? Are they bright enough? The original ones on my car don't throw out much light at all. I'm thinking that it may be because they're tucked way down low below the bumper. I therefore thought that I'd bring them higher, and position them just inside the rear fog lamps, which would occupy their original positions in the new rear end.

I heard from the Poles. They admitted that they were having problems, and told me that they'd lost their moulds. (How on Earth can anyone lose such large items, I wonder?) They asked me to be patient and to wait a couple of weeks, when they hope to be able to send a kit. I always buy stuff through PayPal; so, I know that I'll get my money back if they fail to deliver.