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The mkiv Supra Owners Club

Converting Sequential to True Parallel


ttsupra97

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Hi all,

 

What is the general consensus on a mod like this:

 

http://www.turbofast.com.au/lexusturbo.html

 

For those who like TTC it seems to be the logical next step with benefits being accurate boost control and perhaps more reliability (well, less to go wrong anyway). I would guess that with that setup and a decent 2-1 downpipe directly bolted to the turbo exhausts it would go some way towards reducing the lag that's normally associated with TTC. The reason I'm thinking of it over a single is cost and also the fact that I want the car to still look close to stock. Throw in some more advanced timing down low and maybe it would work pretty well?

 

What's you all reckon?

 

Cheers,

Tony.

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When stock the boost came in very very low down the rev range, almost instantly. But that was due to many other factors other than just the parellel setup. the 1JZ was built to have virtually no lag. The stock CT12a's are tiny ceramic units just for this purpose.

 

With the hybrids, its around 3500 before i hit good boost.

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I would imagine doing this work, as well as getting a proper 2 into 1 downpipe directly off the turbos, along with ignition adjustments across the rpm range would go a fair way to eliminating at least some of the lag of plain ttc, anyone know somebody (aside from Ray Hall of course) that has tried it? I called Ray up a while back to chat about it and he said when he hits the accelerator at 2500rpm it reacts nicely and pulls real hard :) Gotta love the midrange of parallel.

 

Cheers,

Tony.

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Originally posted by ttsupra97

I would imagine doing this work, as well as getting a proper 2 into 1 downpipe directly off the turbos, along with ignition adjustments across the rpm range would go a fair way to eliminating at least some of the lag of plain ttc, anyone know somebody (aside from Ray Hall of course) that has tried it? I called Ray up a while back to chat about it and he said when he hits the accelerator at 2500rpm it reacts nicely and pulls real hard :) Gotta love the midrange of parallel.

 

Cheers,

Tony.

 

I did one, for a pal, ages ago. It was to get around the too small a wastegate sizing and boost creep. I used the pre spool thing as a second wastegate. It was a lot of work and quite a bit of machining, and you still had the horrible stock manifold shape. Far beeter to save and either fit a proper manifold with external wastegate and twins, or a big single. Just wasn't worth the hassle, it was more an excercise in "being different". At the time i wasn't aware it was old hat! Or maybe the Oz people did it after me I would do another, but the price would be high and better put towards a proper set up, IMHO.

 

Actually this pal had a turbo seal go, and he just bolted on a stock turbo pack, it may be the manifold and stuff is still around, but he is in Spain with the car. I could see if I can contact him if you are really keen?

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dunk off this board has true tt mod,a bit of lag then the power comes on strong,i like mine in sequential mode,put your foot down and the pick up is real good.

 

 

ohh that will be me then......oreeet monkey mate....

 

 

yeah personally like the ttc conversion but....can any1 answer me this?

 

if u change to the ttc surely the fuel mapping would need to be differnt? or doesnt the ecu really map the fuel on logarithmic kinda scale...is it just calculated from the airflow sensor?

 

just wondered cos ive killed 4 engines now. :p

 

i changed from sequential bcos i found wiv the boost at around 21 psi i used to get lag at 2500rpm then 4000 rpm this was annoying when racing ppl .....now just get a little lag up to 3k and she pulls really well wiv a deeper exhaust growl

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yeah done just over 10,000 miles since i bought her just over 2 years ago......i treat her really well fully synthetic oil changed frequently.......she never ever sees any boost until the temp guage is reading normal....then im affraid she gets abused....but allways let her cool off b4 turning her engine off.....when i said i change oil frequently well i would but only manage just over 2500miles per engine worst was 60miles best being just over 4000miles.......your all prob reading this thinking what a tail...but its kinda an addiction......a little knowledge can be dangerous...

 

 

:cool:

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think you should be called mad dunk, not seen you on this board much.i keep expecting mine to give way somewhere down the line.not as mad as you dunk but still have my fun.

i dont think i would like to go TTC as i like the power i have, and dont think i could get used to lag down bottom end. dont know how the t78 boys cope some of them big turbos dont come on boost till 4500-5000 rpm

 

lets get team rice back up and running for summer

 

see you later dunk probably at elvington on 27th october. have booked the day off too

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first death was very low compression on on on the cylinders....took the head off and found a small chunk missing from one of the valves... rest of the valve seats were pitted quite bad too...

 

secound time was pistons melted 3 big styley ......

 

had my turbos reconned thou while the engine was out

 

third time was pistons not so spectacular only the one melted this time but it was a nice 1nch square hole all the way down one side of the piston and rings...

 

that time i had been using super unleaded all the time..

 

 

the last time is deffo pistons again.....how many im not sure cos i havnt had time to strip it yet........

 

every time i have had meltdown has always been on hard runs 160+

 

 

but saying that i drove 30 miles down the m18 at 160 to 180 on the clock and she seemed fine....

 

 

@monkey yeah mate looking forward to next season will be a good laugh again...although i have a lot of hard work.....hope i find time to do it....

 

Yeah really looking forward to elvington...missed it last time and was gutted......will be there this time i hope thou....lets hope the runway aint frozen lol

 

:)

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Why not just leave the boost at 18psi?

 

Agreed! But then, some people are destined to repeat their mistakes!

 

Dunk, what mods do you have on your car to safeguard the engine? Water injection? Better intercooling? I guess none of the above...

 

It is distressing to hear of someone melting their pistons, but to do it three times almost beggars belief!

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nope no other safety measures ....thought about water injection and fmic......but never got round too it...will do 1 day.....

also meant to get a egt guage ...but never got round to that either...

 

 

personally dont think it makes more boost at 18psi think ur slightly confused.....i have heard rumours that standard tubos loose there effieciency over 18psi ...........but dosnt mean its going to produce less power.....

 

ive had my apexi avcr set at all difnt boost levels and prefer 21psi

 

yes what ive done is slightly idiotic .....but hey never mind u live n learn fifth time lucky.....maybe...?

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its yr fueling at 21 psi, i reckon. the stock MAP sensor voltage peak is around 18 psi, so any boost after that is being fueled by the fuel map for 18psi, which isnt enough, as u already know :)

 

the stock turbos will produce more power after 18 psi, but it starts to fall off fast

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