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[Mk2] [Turbo] Stuff on the net

 
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blogsy




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PostPosted: Thu Jul 20, 2017 9:44 pm    Post subject: [Mk2] [Turbo] Stuff on the net Reply with quote Reply with quote including images

Just have to ask this. If a car hits knock at 1.1 bar with a Apexi power ecu but makes 283hp at the flywheel on standard pistons , why would forged pistons make any difference. It will still set of knock at 1.1 bar.
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androo007
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1994 Toyota MR2 Mk2 Turbo Rev3

PostPosted: Fri Jul 21, 2017 5:26 am    Post subject: Reply with quote Reply with quote including images

When you put forged pistons in the car you can lower the compression which typically reduces the chances of knock on the same scinareo as standard pistons.

However knock isn't something that's prescribed at a particular boost level, if you are seeing knock you need to look at your setup and see what the weak link is, or run higher grade fuel.
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Gazza_DJ
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1997 Toyota MR2 Mk2 NA Rev4

PostPosted: Fri Jul 21, 2017 9:37 am    Post subject: Reply with quote Reply with quote including images

androo007 wrote:
When you put forged pistons in the car you can lower the compression which typically reduces the chances of knock on the same scinareo as standard pistons.

However knock isn't something that's prescribed at a particular boost level, if you are seeing knock you need to look at your setup and see what the weak link is, or run higher grade fuel.


xxxx map by the sounds of it...
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Dale_V




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PostPosted: Fri Jul 21, 2017 10:31 am    Post subject: Re: [Mk2] [Turbo] Stuff on the net Reply with quote Reply with quote including images

blogsy wrote:
Just have to ask this. If a car hits knock at 1.1 bar with a Apexi power ecu but makes 283hp at the flywheel on standard pistons , why would forged pistons make any difference. It will still set of knock at 1.1 bar.


forged pistons wont stop it knocking, the'll just "cope" with the knock more than stock pistons will. The solution really is to tune properly as previously stated.
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Martin F
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1994 Toyota MR2 Mk2 Turbo Rev3

PostPosted: Fri Jul 21, 2017 4:19 pm    Post subject: Re: [Mk2] [Turbo] Stuff on the net Reply with quote Reply with quote including images

Dale_V wrote:
blogsy wrote:
Just have to ask this. If a car hits knock at 1.1 bar with a Apexi power ecu but makes 283hp at the flywheel on standard pistons , why would forged pistons make any difference. It will still set of knock at 1.1 bar.


forged pistons wont stop it knocking, the'll just "cope" with the knock more than stock pistons will. The solution really is to tune properly as previously stated.


So in theory you could run 500 bhp on standard pistons, the ringlands being the weak link obviously though [Think]
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Dale_V




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PostPosted: Fri Jul 21, 2017 4:41 pm    Post subject: Re: [Mk2] [Turbo] Stuff on the net Reply with quote Reply with quote including images

Martin F wrote:
Dale_V wrote:
blogsy wrote:
Just have to ask this. If a car hits knock at 1.1 bar with a Apexi power ecu but makes 283hp at the flywheel on standard pistons , why would forged pistons make any difference. It will still set of knock at 1.1 bar.


forged pistons wont stop it knocking, the'll just "cope" with the knock more than stock pistons will. The solution really is to tune properly as previously stated.


So in theory you could run 500 bhp on standard pistons, the ringlands being the weak link obviously though [Think]


Yeah.. I guess they could make 500bhp, but they wouldn't last any length of time
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Gazza_DJ
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PostPosted: Fri Jul 21, 2017 4:48 pm    Post subject: Reply with quote Reply with quote including images

I'm sure I recall a thread on here 2 or 3 years ago of someone trying to achieve that on stock internals [Think]
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blogsy




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PostPosted: Fri Jul 21, 2017 9:09 pm    Post subject: Reply with quote Reply with quote including images

I realise this don't really make any sense and is a bit ar$e about face, but could I bolt on a gtx3071 and bold on some bigger injectors and run it again on the rollers till it knocks and maybe get 330ish without the ringlands going. I would need to get the turbo and the injectors anyway if I was going to do it properly.
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pbmr2
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PostPosted: Sat Jul 22, 2017 7:22 am    Post subject: Reply with quote Reply with quote including images

Why do you think it's knocking?

what year engine do you have?
what mods are on the car?
who mapped the ecu?
do you have a wideband gauge?

A 3071 turbo will make well more than 330, even on stock pistons, but the other mods around it is what is needed to make this possible.

If there are other issues with the current setup then they would just transfer to the next power goal if not addressed. You may have a simple issue now that is causing your current situation (why do you think it's knocking?) that if fixed could see another 20+hp without further mods.

Bolting on a turbo without the other parts of the system able to keep up, will most likley just casue more issues and make the car slower in the lower rev range.

Need a bit more background and info. good luck
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Al-sw20




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1991 Toyota MR2 Mk2 Turbo Rev1

PostPosted: Sat Jul 22, 2017 9:52 am    Post subject: Reply with quote Reply with quote including images

Gazza_DJ wrote:
I'm sure I recall a thread on here 2 or 3 years ago of someone trying to achieve that on stock internals [Think]


Yep managed to do it to, for quite some time, despite the naysayers.

Ran 11.7 @ 120mph, 487bhp? Stock internals, head gasket and clutch.
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blogsy




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PostPosted: Sat Jul 22, 2017 7:22 pm    Post subject: Reply with quote Reply with quote including images

It's knocking because all rev3 turbos with the usual mods of air filter, exhaust, de-cat, st205 charge cooler and wolbro pump knock at that sort of power, 280ish at 1.1bar. Some get 300hp at 1.2bar, but they all hit their limits around this kind of boost and hp area, I'm sure you'll all agree. The mapper advanced it til he got knock then brought it back a bit, 283hp 1.1bar. If I fit a gt3071 and bigger injectors would I get the same result at 0.8 bar? But not see any knock till 1.1bar and by that time be making a lot more power. Why? Because it's 7000 for 400+hp or 2000 for a turbo/injectors and maybe 350hp. And yes I have had a beer it is Saturday night [tongue]
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