1.8T track car engine tuning G25-660

[Stuart B]

Is there more to this than temperature? I am holding off replacing my exhaust valves at the moment as "the best thing to do is to replace them to Inconel for peace of mind" but is that because of the EGT or what else? as Tuffty has plots showing about 600bhp and 580 Deg C EGT so why need them on that type of setup - whereas my TT was showing up to 920 Deg C in the summer at 19psi with FMIC - but if BTS Me7 intervention cuts in from 900 Deg C are Inconel definitely required for a medium stage 2+ build?


This has lots of info but not sure how applicable ?

http://ssvalves.net/Engine_Valve.aspx

I was on a site the other day where you could pick the type of valve material they ranged from £6 to £35 each.

 

[<tuffty/>]

Is there more to this than temperature? I am holding off replacing my exhaust valves at the moment as "the best thing to do is to replace them to Inconel for peace of mind" but is that because of the EGT or what else? as Tuffty has plots showing about 600bhp and 580 Deg C EGT so why need them on that type of setup - whereas my TT was showing up to 920 Deg C in the summer at 19psi with FMIC - but if BTS Me7 intervention cuts in from 900 Deg C are Inconel definitely required for a medium stage 2+ build?


This has lots of info but not sure how applicable ?

http://ssvalves.net/Engine_Valve.aspx

I was on a site the other day where you could pick the type of valve material they ranged from £6 to £35 each.

OE exhaust valves are sodium filled to help combat temps...

Bill has cut a few OE exhaust valves open only to find the sodium has dried out...

Inconel is a super alloy and is designed to withstand higher temps associated with exhaust gasses... the turbine wheels in turbo's are typically made from inconel... inconel fixings are used in turbo applications as they resist high temps and don't stretch as easily...

OE exhaust valves are generally replaced due to the fact they are a point of failure... stage 2 or big turbo... the temps are still there... granted mine are a bit lower but I measure mine post turbine and I have a more efficient setup that prevents exhaust gasses from backing up... K04's in std or hybrid form WILL run hot as the flow through the mani, hotside, turbine will be more restrictive allowing heat to back up...

You can't really compare my EGT's to this... its all relative...

OE exhaust valves are generally past their sell by date on most 20v's now... when valves fail its pretty much always the exhausts... and they fail a lot more regularly...

Pressure ratio is key... you can see twice the inlet pressure in the exhaust manifold (sometimes more) due to small hotsides/turbines/inefficient manifolds etc... this allows heat to build and raise EGT's...

I saw 1000+ on my old GT30 setup at the collector.... 900 odd when I moved the probe post turbine...

The only choices for a turbo engine are sodium filled or inconel... Supertech now do sodium filled inconel valves too... if rebuilding the head (exhaust guides will need replacing at the very least and you should consider replacing the exhaust valves at any level of tune IMO...

Standard stainless valves are not suitable for turbo applications of any level of tune...

<tuffty/>

 

[Stuart B]

Okay so replacing with stock is better than keeping original, but nowhere near inconel?

 

[<tuffty/>]

Okay so replacing with stock is better than keeping original, but nowhere near inconel?

New stock ones yes... But iirc they are almost as expensive to buy as inconels

<tuffty/>

 

[Stuart B]

I need to slow down, I had a plan and a time scale and as always trying to rush and short cut. Thanks for your excellent advice and explanation as always

 

[Warsuperior]

@desertstorm any news about turbo? have you got it running? Im trying to decide which turbo for stroker engine. G25-660 is in my mind

 

[desertstorm]

Running in at the moment going OK. Need to do about another 150 miles then swap to fully synthetic oil and start winding up the map. In La for the next 3 weeks for series 4 battlebots filming with team Monsoon so car just sitting in the garage ATM.

 

[Nizza]

Running in at the moment going OK. Need to do about another 150 miles then swap to fully synthetic oil and start winding up the map. In La for the next 3 weeks for series 4 battlebots filming with team Monsoon so car just sitting in the garage ATM.

How's the car going?? . Just reading this up as I'm trying to build a parts list for a 450bhp bam engine, turbo choice is either the g25 550 or the gtx3071r gen 2.

Would be really helpful.

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[desertstorm]

@Nizza Car is all sorted now. 511 bhp 370Lb/ft . Details are in my track car build with the link at the bottom of this post in my signature. Have a look at Badger 5's site on facebook there is a lot of dyno stuff and comparisons between G25-550 and 660's.
If 450bhp is your target then the G25-550 would be your turbo of coice.
Definitely change the standard cams. I changed the intake cam on mine for a Normally Aspirated item and picked up another 40-50bhp.

 

[Nizza]

@Nizza Car is all sorted now. 511 bhp 370Lb/ft . Details are in my track car build with the link at the bottom of this post in my signature. Have a look at Badger 5's site on facebook there is a lot of dyno stuff and comparisons between G25-550 and 660's.
If 450bhp is your target then the G25-550 would be your turbo of coice.
Definitely change the standard cams. I changed the intake cam on mine for a Normally Aspirated item and picked up another 40-50bhp.

Great info I'll take a look at your thread although I'm not on. Fb. It will be visiting b5 when done.

450 is ideal for me as its track use so will be wound down a bit for all day abuse.

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[desertstorm]

@Nizza I think Badger 5's site is public on FB so you should be able to see the content. https://www.facebook.com/Badger5Ltd/

 

[badger5]

Great info I'll take a look at your thread although I'm not on. Fb. It will be visiting b5 when done.

450 is ideal for me as its track use so will be wound down a bit for all day abuse.

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www.badger5.co.uk has live update stream to our fb page also fyi
updates are posted on facebook