All top end on a tuned uk spec?

I now have a blitz SBC-ID, decat and nurspec on my UK spec. Im finding that theres normal levels of performance below 4500rpm and then once it hits 4500rpm it really had a kick. This is completely different to my import which used to kick at about 3000rpm.

 

The SBC shows that turbo1 is making boost (up to about 0.6 or so), and the second turbo can happily hit 1.2bar, but below 4500rpm theres really no major acceleration. I can just about keep it in the power band if I rev to red line each time, but if it drops below 4500rpm on the gear change then it bogs down.

 

Is this normal for a modified UK spec?

 

JB

EVERY uk spec car I have driven has had far more lag than a J-Spec. Donning flame proof overalls I would never, ever buy a UK spec for myself, IMO the Jap specs drive better, have more power, and FAR less lag. UK specs seem to vary enormously, in my experience a "good" UK spec is about as quick as an average J-Spoec. A strong stock J-Spec is invariably faster than any UK stock cars i have encountered. Gearing may have a lot to do with it, as well as the AFM and turbo sizing in the UK spec cars. Ignition mapping will have a large say too, the UK cars are more retarded than J-Specs, probably to allow for our *rap fuel. UK's with hybrids can be `orrible, especially as an automatic.

 

I'd need to actually drive yours to say if it was normal or not, surely with the garage business you get to drive plenty of Supras, or don't you involve yourself with that side of things (I thought I read you and Justin were partners, or have I got it all wrong?) Anyway, it sounds familiar, but how much lag is normal, and at what RPM it all happens is hard to descibe in words :-)

That probably confirms it for me, I said to Barry on the phone today that even my tuned UK spec wouldnt be as quick in every day driving as my old import. I can put up with the lag and drive round it when needs be, just thought I would see if anybody else has experienced it.

 

I was sort of close to being a partner with Justin, but in the end it was just the web site that I built. His business was moving so fast I didnt have time or money to invest in it. Which also means I dont get to drive all his great toys.

 

Leon also said it was pretty normal for UK specs to do that, but it was just so different from my decat import that I had to ask.

 

I will try and get in another UK spec manual at some point and see how it behaves, there seems to be a few of them around now...common as muck

 

JB

Branners,

 

If it makes you feel any better about your UK spec...I wasted Gavin's on the strip mainly cause his only got going over 50mph....which is too late on the drag strip. If it was a half mile he would have won...

 

But if I read your settings correctly on the other page about the SBC...then your gain is WAY too low. 9 just isn't worth it!

 

20-30 maybe more on a UK....I run 20 on my j-spec.

CH4 on the SBC is set to 70 with a gain of 20, so it should still spool properly. I only use 10 for CH1 which is my wet weather setting.

 

I still recon I can 1/4 mile the thing in mid 13s, hopefully I will find out next year.

 

JB

Originally posted by Chris Wilson

EVERY uk spec car I have driven has had far more lag than a J-Spec. Donning flame proof overalls I would never, ever buy a UK spec for myself, IMO the Jap specs drive better, have more power, and FAR less lag. UK specs seem to vary enormously, in my experience a "good" UK spec is about as quick as an average J-Spoec. A strong stock J-Spec is invariably faster than any UK stock cars i have encountered. Gearing may have a lot to do with it, as well as the AFM and turbo sizing in the UK spec cars. Ignition mapping will have a large say too, the UK cars are more retarded than J-Specs, probably to allow for our *rap fuel. UK's with hybrids can be `orrible, especially as an automatic.

 

I'd need to actually drive yours to say if it was normal or not, surely with the garage business you get to drive plenty of Supras, or don't you involve yourself with that side of things (I thought I read you and Justin were partners, or have I got it all wrong?) Anyway, it sounds familiar, but how much lag is normal, and at what RPM it all happens is hard to descibe in words :-)

thats nice to hear when all the uk supra boys take the piss out of j-specs for having small brakes,turbos, as well as other things.

kind of makes you smile.

wonder how stock for stock go against each other JAP auto v UK auto and JAP manual v UK manual.

i got beat by michael off this board in his 6speed nos car at dragstrip. i am happy with mine most of time, getting better off line now. and got loads of pull from low down to 100+ then just back off. its good to see how it goes against other supras. not that we get much of a chance.

you know if you get into 12`s that its a pretty fast car.

what sort of mods did you have on your jap car?

Originally posted by MONKEYmark

thats nice to hear when all the uk supra boys take the piss out of j-specs for having small brakes,turbos, as well as other things.

kind of makes you smile.

 

A new one on me. I rather thought this BBS was devoid of that sort of thing or is someone being a bit over sensitive?

Originally posted by GavinL

A new one on me. I rather thought this BBS was devoid of that sort of thing or is someone being a bit over sensitive?

 

Yeah.

 

Obviously they are different between the cars but thats to be expected. Some of things I've known about the Jspecs make them better cars - at least if your a performance nut...

 

Gaz.

Write the gloves are off,

now who's got a j spec tt and wants to race and is in the w mids,

im ready for all comers so bring it on:) er just no big singles or hybrid jobbies t/y

 

But on a serious note i'd have to sort of agree with the uk tt being a bit ishh out the blocks, ive not been in a j spec tt with same mods as my uk car so cant really compare.

 

But at least us uk boys can stop and as we all know power is nothing without control :D

Only jocking guys, weve all got mkiv's just with diff bits bolted on them, which most of us seem to modify anyway, there cant be many totally stock cars here.

Im still more than happy with my UK spec, having to pay 50% less for insurance for the same mods makes me very happy.

 

The Santa Pod quarterly 1/4mile competitions next year should show what the cars can do. Ibrar has also agreed to sponsor each event ( http://www.pro-wheels.co.uk ) with a small trophy for the fastest stock turbo based car, and Barry has (next time I see him) the big trophy for the fastest stock turbo based Supra at Pod so if anybody beats 12.9 then the big trophy goes to them.

 

Early RWYB Pod dates for next year are Jan 26th, Feb 2nd, Feb 16th, Feb 23rd, Mar 2nd, Mar 16th, Mar 30th and Apr 6th. So if we go on Jan 26th we can then have the next events in Apr, July and then October.

 

I will post this in events so everybody knows about it.

 

JB

Originally posted by Branners

I now have a blitz SBC-ID, decat and nurspec on my UK spec. Im finding that theres normal levels of performance below 4500rpm and then once it hits 4500rpm it really had a kick. This is completely different to my import which used to kick at about 3000rpm.

 

The SBC shows that turbo1 is making boost (up to about 0.6 or so), and the second turbo can happily hit 1.2bar, but below 4500rpm theres really no major acceleration. I can just about keep it in the power band if I rev to red line each time, but if it drops below 4500rpm on the gear change then it bogs down.

 

Is this normal for a modified UK spec?

 

JB

 

 

Branners

- what you wrote above almost exactly mirrors what my UK-spec car was like. The big kick came in about 4500-4800rpm when 2nd turbo came on-line properly. below that level it accelerated, but like you, it didn't feel that much different to stock performance below 4000rpm-ish.

 

Also on the power-band thing, i know what you mean too, because at Silverstone at Trax 2001, the car used to just fall out of the power-band on change-ups, (say the next gear engaged at about 4500rpm on red-line upchanges), which meant a small delay before the next big surge.

 

So I would say your car is entirely typical of a UK-spec manual with the level of mods you have. The only difference really between your car and my old UK-spec being that i had a bleed valve on mine and you have an EBC.

 

are you doing any more mods to it ? RLTC ? FMIC ?

 

cheers

Originally posted by GavinL

A new one on me. I rather thought this BBS was devoid of that sort of thing or is someone being a bit over sensitive?

not over sensitive, read loads of post of uk boys putting jap cars down.having digs at small brakes and less bhp smaller turbos, dont say you have not seen it on boards.

i love a good barney and banter. we used to have some right fun with some mr2 lads from newcastle who we know.

its just good to see someone praising a jap spec for once. and by someone who knows there stuff and has driven loads.

only ever been in 1 other supra and it was mates ttc uk supra.

50% difference in supra insurance is good thing, but with insurance been so wildly different from area to area and dependent on age NCD.it is not a factor for me. i bought the supra and knew insurance and running costs would be high and aint put me off.

if i knew a bit more when i got mine i would have stuck out for what i would have wanted a white facelift uk 6speed,

just have to be happy with what i got and make it as good as i can speed wise.

who would buy a supra again in standard spec.it would feel too slow after getting used to de catted + exhaust.

its good to see the big power supras in usa in action.cant wait till next year starts up again.

 

have fun

 

ps branners santapod sounds like it could be a laugh, a bit of competition for us all. also shouldnt barry do his own 12.9 1/4 if he has your old car. it will be good to been the first person with there name on the big trophy (only kidding for all those people who cant take a joke)

Originally posted by Doughie

Branners

- what you wrote above almost exactly mirrors what my UK-spec car was like. The big kick came in about 4500-4800rpm when 2nd turbo came on-line properly. below that level it accelerated, but like you, it didn't feel that much different to stock performance below 4000rpm-ish.

 

Also on the power-band thing, i know what you mean too, because at Silverstone at Trax 2001, the car used to just fall out of the power-band on change-ups, (say the next gear engaged at about 4500rpm on red-line upchanges), which meant a small delay before the next big surge.

 

So I would say your car is entirely typical of a UK-spec manual with the level of mods you have. The only difference really between your car and my old UK-spec being that i had a bleed valve on mine and you have an EBC.

 

are you doing any more mods to it ? RLTC ? FMIC ?

 

cheers

 

RLTC will have to go on it at some point, just not worth taking the chance with the way the power is delivered.

 

Leon has some thoughts on how to beat the severe lag on the UK specs so I will chat to him more about it to see what can be done. I suppose the other option is to use the mod that Richard J used on his old Supra to get the first turbo to boost up way more than normal. Has anybody else done his mod and found it works well?

 

JB

Originally posted by MONKEYmark

not over sensitive, read loads of post of uk boys putting jap cars down.having digs at small brakes and less bhp smaller turbos, dont say you have not seen it on boards.

 

Go on then show me loads on this BBS and whilst your at it you had better include one from me if your going to use sweeping generalisations

Originally posted by GavinL

Go on then show me loads on this BBS and whilst your at it you had better include one from me if your going to use sweeping generalisations

as if i am going to waste my time searching for posts.not getting into an argument with you. got better things to do

 

have a nice day

OMG! 4500 RPM to get a kick. I have to praise the jap spec here as the torque and response is phenomenal. I run with a 30% mix of toluene in my jap spec to get close to 98 Octane. Running boost of 1.1 bar and trying to launch as low as 1800 RPM is a real challenge as the wheels simply break loose even crusing on 2nd at 2500 RPM and punching it down makes the wheels spin.

JAP SPEC =TORQUE KING!! :flame Dev

SO U UK SPEC GUYS WATCH OUT!!

Originally posted by MONKEYmark

...smaller turbos

 

Thats actually wrong, Jap specs have bigger inlet/exhaust housings...

 

Gaz.

Originally posted by gazwalker

Thats actually wrong, Jap specs have bigger inlet/exhaust housings...

 

Gaz.

something that you never are

 

so you going to have a go in yours? or is it a show car?

 

you got the boost controller and decats exhaust and what ever else

 

dont the jap have more torque than uk too, think i read it somewhere,tell me im wrong again

 

should be a good laugh if a few supras are racing.never been to santapod, looks a top track with times above lanes.

team rice for life

Originally posted by MONKEYmark

something that you never are

 

Maybe

 

so you going to have a go in yours? or is it a show car?

 

I might, however I'm going single turbo mid next year so I don't think I'll qualify...

 

dont the jap have more torque than uk too, think i read it somewhere,tell me im wrong again

 

Probably, lots of different figures thrown about, I wouldn't argue either way...

 

should be a good laugh if a few supras are racing.never been to santapod, looks a top track with times above lanes.

team rice for life

 

Its good that way, but the grounds are shite, the road there and inside the place is shocking.

 

Gaz.

Originally posted by gazwalker

Maybe

 

I might, however I'm going single turbo mid next year so I don't think I'll qualify...

 

Its good that way, but the grounds are shite, the road there and inside the place is shocking.

 

Gaz.

you not scared about loosing are you? its about having fun and seeing what your car can do and taking part. there is always going to be a faster car round corner.i love having a race with skyline lee just to see how i can go against him.i know i wont beat him but i try.

santapod cant be anyworse than york dragway its a right hole but gets you out for the day with your mates.

i would like a single turbo but would be a longway off knowing you will have to get uprated fuel system too.dont know what else to do on my car. not got any fancy electronics or boost gauges.might look into that next.

that lad off here with the supra N/A gave his a go and i bet he had a load of fun.

 

i dont mind loosing to anything as long as i get a buzz

Originally posted by MONKEYmark

if i knew a bit more when i got mine i would have stuck out for what i would have wanted a white facelift uk 6speed,

 

You would have to be an extremely patient guy.

 

JB - I have a feeling that mine kicks earlier than this, but i'm not 100% sure. As it's all tucked away for a few months now i can't confirm till next year. However i think as Alex says you want to try upping the gain on your SBC-iD a bit and see if this helps. As long as you check the peak reading after each run you can keep and eye on any boost spikes.

 

 

Contradicting Stu a bit (amusing, as we're talking about the same car) but I find I get a decent pull from 2500rpm or so, 3000rpm is pulling well (certainly all I need on wet roads), the usual drop, then a violent surge starting at 4000.

 

Having a bit of a play this morning, I reckon it's probably more to do with the difference between single and twin behaviour on the two types. J-specs make their torque earlier (as we all know), but when a J goes twin it's less of a difference whereas a UK starts lower at the change, but goes higher, making for a more pronounced kick.

 

Does that make sense?

My UK TT is exactly the same JB.

Nothing spectacular happens until I start to get over 4000rpm but then a real surge.

I'd be interested in trying to improve the response lower down but wouldn't have a clue how it could be achieved.

You could try a temporary true-twin conversion . . .

Originally posted by Adam Wootten

You could try a temporary true-twin conversion . . .

 

Why "temporary" i'm going for a true tt soon