Auto tranny max HP

Hey guys,

im planning to bpu/+ my TT. Do i have to change my tranny in any way? Should be about 450hp.

Second question. If i upgrade to HKS twins (aprox. 600hp) are there any changes needed?

greetz

carsten

Hey guys,

 

im planning to bpu/+ my TT. Do i have to change my tranny in any way? Should be about 450hp.

 

Second question. If i upgrade to HKS twins (aprox. 600hp) are there any changes needed?

 

greetz

carsten

1) Your auto box will be fine up to that BHP, regular oil changes will be good or some coolers.

2) To upgrade to HKS twins you will have to change a fair bit. Including swapping your auto for a manual.

Ouch.

Okay. So HKS twins will cost A LOT more then expected

So how much BHP could i run on the stock tranny? (maybe with high stall converter).

Ouch.

 

Okay. So HKS twins will cost A LOT more then expected

 

So how much BHP could i run on the stock tranny? (maybe with high stall converter).

Your auto will only go up to 450ish from what I've read but I heard the yanks talking about shimming the accumulators to get it to handle more. It makes the shifts a lot harder but the clutch packs don't heat up as much or so they claim anyway.

To see 450bhp from BPU upgrades you will also have to spend quite a bit to get to that level too. If needing all the parts maybe around £4k maybe less.

Hybrids

Boost controller

Fueling

Cams

Piggyback or standalone ECU

etc etc

(some of the above depends if you have a J-Spec Supra)

Running stock turbo's and doing the basic's for BPU I would expect to see at the most 400bhp. At the wheels BHP will be a lot less than that as you are running an autobox, maybe 340-360 ish. All figures are estimates, as there is so many variables.

Best to cost it all out and you may find it will be better to save and maybe go single. As to aim for 450BHP at BPU level is a wait of money if then plan to go single or big twins.

Hey guys,

 

im planning to bpu/+ my TT. Do i have to change my tranny in any way? Should be about 450hp.

 

Second question. If i upgrade to HKS twins (aprox. 600hp) are there any changes needed?

 

greetz

carsten

450hp is manageable but you are starting to eat into the life of the box at these power levels, mine started to go at this level then a single turbo finished it off , please do some research before rushing off to buy a HKS twin install on an auto, it is not the best combination and with the power level you are talking about a single would be much better option with about 1200-1500 rpm less lag

Thats right Paul.

A single would be better for those BHP levels.

But i like the function of twins and i still want to be the exot of the exotics

But what i heard from now.... Think ive to rethink my plans.

A smaller single could produce about 550bhp. Someone told me, that a stock auto tranny (with proper cooling) could stand this power. What do you think? How far can i go to drive savely.

450 - 500 max bud.

But i like the function of twins and i still want to be the exot of the exotics

Could be something is lost in translation, but what function do you think you would get from big twins that you would not get with a single?

But what i heard from now.... Think ive to rethink my plans.

A smaller single could produce about 550bhp. Someone told me, that a stock auto tranny (with proper cooling) could stand this power. What do you think? How far can i go to drive savely.

It's not the HP that matters, it's the torque and a small single make a LOT of torque. With some serious additional box cooling you'd be looking at 450-500 ib/ft and 500-540 bhp at the upper end of the stock box.

Another option is to replace the box with a BL auto one but that tends to be as expensive as changing to a manual.

Hm i start to get sad -_-

Stupid auto. Upgrading it is kinda expensive.

As i have a jspec supra i cant go over 400-450bhp with the stock twins. So would you prefer changing to a small single (a.e. a gt35, aprox 500bhp with autobox cooling) or upgrading to uk/eu spec twins?

Hm i start to get sad -_-

 

Stupid auto. Upgrading it is kinda expensive.

 

As i have a jspec supra i cant go over 400-450bhp with the stock twins. So would you prefer changing to a small single (a.e. a gt35, aprox 500bhp with autobox cooling) or upgrading to uk/eu spec twins?

The change to export spec turbo's is not worthwhile, it'll loose some of that lovely mid range torque but only gain a few BPU at the top end, plus you'd need larger injectors, mapped ECU, etc. An expensive exercise for almost no gain.

A small single would allow you to get to 500bhp and have good driveability, but to do it correctly is also expensive, the cost of changing to a manual is quite small in comparison. If you have the funds to convert to a small single (or even big twins) then the gearbox change is pocket change

If I were in your shoes and preferred the manual gearbox, I'd go for a T67 single and R154 gearbox if the V160 is too much.

I'm 30 brake down on a UK spec. My dyno curves are very smooth compared to said UK though. Almost no hesitancy in the sequential transition to no.2 coming on line compared to a marked differential in the same area for the UK. The smoothness of this car is stopping me going BPU. I don't wanna FIU.

Thanks Homer.

Originally the topic was about changing the auto to manual because (i thought) the auto couldnt handle much power.

I would like to stay/keep at my auto (or upgraded) and drive about 500bhp. Thats my goal.

So thats why i planned to go with a gt35 and a cooled auto. If that is not stable, meaning my auto will break soon or later, ive to think of something else.

Thanks Homer.

 

Originally the topic was about changing the auto to manual because (i thought) the auto couldnt handle much power.

I would like to stay/keep at my auto (or upgraded) and drive about 500bhp. Thats my goal.

 

So thats why i planned to go with a gt35 and a cooled auto. If that is not stable, meaning my auto will break soon or later, ive to think of something else.

As you are not a member here you won't be able to see the very detailed thread from Lui, who took exactly the same route.

He had a BPU jspec TT and wanted the single, but wanted to keep the auto. He used a PHR stage 1 turbo kit (very similar to the GT35), fitted a very large cooler but had to keep boost to less than 1.3 bar. I think it was finally dyno'd at 509bhp at the flywheel. He is VERY happy with it, but the boost is held back due to the auto box. At least going this route you have the option for more power if you want to change the gearbox in future

Wow.

Thats exactly what i want

If the turbo produced 500bhp @ 1.3 bar thats totally okay.

So thats my goal for the next year Thanks mate.

ps: i just pm´ed mawby for the club membership. Need more information for the banking Transfer germany->uk

Wow.

 

Thats exactly what i want

If the turbo produced 500bhp @ 1.3 bar thats totally okay.

 

So thats my goal for the next year Thanks mate.

 

ps: i just pm´ed mawby for the club membership. Need more information for the banking Transfer germany->uk

No problem, PM me for membership stuff please

i wouldn't get to hung up on the fact the auto box will fail at the 500 + hp mark, it wont fail with a bang and wipe out your car it is more of a graduall loss of performance, when this happened to me i only drive autos so wanted the best i could get which was a Boostlogic built auto, i could have done it a lot cheaper by swapping the box for another stock one and with all the budding F1 drivers on here who's talents far surpass the humble auto they are ten a penny you could pick up a good condition auto box for peanuts and get another year or two out of it before you had to swap again

I would stick to your auto box until it gives up and put a boostlogic one in or get one of the upgrade kits out of the U.S. for your own box. Does anyone know what sort of power Robbie and Dude are putting through there boxes? It must be a right big amount there are the two of the quickest cars in the club doing 1/4 mile with only Envys animal being quicker

Yeah, i stick to my auto and upgrade to the kit that Lui uses.

The upgrade kits still only change clutch packs though, the bits inside stay the same for the most part. If the clutch packs are upgraded and therefore don't slip under serious torque then all the stress just gets passed along to something else, Yanks say the next thing to go is the 2nd gear sprag whatever one of those is.

I spent a long time searching for info on auto box cars with 500+ bhp. Built boxes were expensive and those in the states needed rebuilding frequently. The other option was to move away from Toyota boxes and go Power Glide or TH400, but these are for really big power and total over kill for the power levels you are seeking. With the right torque converter both will handle well over 1000 bhp.

With all auto boxes, by nature of design, heat is the biggest killer. If you want to keep the auto driveability and performance, go Lui's route with a small single. Just invest in a very good cooling system and the box will hold up well.

The MKIV TT box is an amazing gear box, combined with a small single, you will out perform six speed box cars, with similar power, at road legal speeds. Boxes are cheap to buy second hand so picking up reliable spare costs £250 - £350. If you are considering regular power break starts, buy a few spare boxes:innocent:.

This old thread from Supra forums has loads of info on the workings of the box and how to keep it sweet. You have to pick your way through, it as reading it end to end could result in loosing the will to live;)

MKIV Auto Box making it last

Any updates on newer tech to make autobox take bigger hp. I want 700bhp and not willing to pay 5k for a 6speed. Is there any alternatives in 2018?

Any updates on newer tech to make autobox take bigger hp. I want 700bhp and not willing to pay 5k for a 6speed. Is there any alternatives in 2018?

We run a Stage 3 SRD built auto that can cope, remember though it’s torque and heat that kills autoboxes not outright power. We make around 750bhp/600+lbft on full kill mode and the box has been fine for over a year. But we don’t drive it hard all the time, maybe work contacting Lee at SRD for further details.

Any updates on newer tech to make autobox take bigger hp. I want 700bhp and not willing to pay 5k for a 6speed. Is there any alternatives in 2018?

I run over 700hp on mine through an SRD stage 3 built auto with no problems but you will still require some additional cooling

Yeh I'd go built SRD auto with extra coolers if I wanted big power from my TT auto... my N/A 5 is going in for an M3 6 speed swap in a couple weeks so will be interesting to see what that's like!