Big turbo, little turbo and engine capabilities

Hi guys

I've been doing some poking around on SF on stock(ish) engines and safe power capabilities. Now I know this has been done to death on here but I read this on SF which made me think.

Basically on a few occasions I read that the engine could handle more or handle the power better if it was progressive. What I mean by this is it doesn't just come in in 1 almighty bang. So this got me thinking about turbo size.

Now the likes of a billet turbo the power is there straight away which will really stress the engine going from nothing to everything.

So could an engine be pushed that little bit further with a bigger turbo that takes slightly longer to spool. Hence not giving the engine an instant shock so to speak.

I know it's been said many times that around 700hp is about the limit for a stack block, BUT with some artwork from Lee.P these boundaries have been pushed and pushed by Jamie and Jamesys cars.

So I'm thinking, with a turbo such as mine GT42-76, which spools a lot slower than the billets these guys were running could the power boundries be pushed that little bit more.

Here's my engine spec. I havnt included the fuel system as it needs amending but what do you think.

Stock pistons

Stock rods

ACL main bearings

ACL end bearings

ACL thrust washers

ARP main bolts

ARP rod bolts

ARP head studs

PHR oil pump

ATI pulley

New Toyota water pump

Ported head

264 cams

HKS pulleys

GT42-76 turbo 1.28 A/R (may be changing to 1.01A/R)

Whifbitz manifold

Tial 44mm wastegate

Screamer

4" exhaust

Veilside plenum

Veilside 100 throttle body

Veilside rail (-6AN duel feed)

Aeromotive FPR

1600cc RC injectors

Greddy 4 row

4" intercooler pipework.

Syvecs Solaris S6 ECU.

A/C removal.

25 row oil cooler

10 row PAS cooler

Good question - but wont changing your A/R to the smaller 1.01 make it spool quicker though mate - you sound like you want to go the other way - slow spool big power- the A/R 1.28 would suit better id have thought

I don't think a 1.28 A/R will be at full boost until over 5K and I don't think I could live with that to be honest mate. I'll leave it in place for it to be mapped though and see how it goes before I look at changing it.

good thread john, im building mine at the moment so might come in handy.

i have JE pistons in mine

A slower spooling turbo will be less stressful on the engine for sure, push it hard i say, worst happens fix it.

A slower spooling turbo will be less stressful on the engine for sure, push it hard i say, worst happens fix it.

I was waiting for you to post mate. And your reply was exactly what I anticipated lol.

Don't get me wrong, I don't want to pop the engine but I've fitted ARPs all through the engine which are known weak spots in a pretty bulletproof engine as is. On the back of this I would have thought with slower spool 800hp is safely achievable using pump fuel.

Good thread, what rpm limit are you planning hodge?

Good thread, what rpm limit are you planning hodge?

That's going to be Ryans jobs mate. I'll be leaving it totally in his hands. I trust whatever he thinks best.

This is the technique that most of the Australian tuners use (and Scandinavians too, so I hear) - high boost, low timing = big numbers without race fuel.

Thunk I'll have a big on supraforums.AU tonight while I'm at work to see what I can find.

There are a few big numbers there.. forums have been dead past year though.

I've been a member on there for a couple of years but havnt really posted much. I'll see what I can dig up.

PROJECT GOLD RUSH

rebuilt and balanced bottom end with stock head

JE pistons/rings

acl bearings

rod bolts

new oil pump

new water pump (toyota)

rod bolts ARP

ARP head studs

engine gasket set (complete) toyota

greddy intake manifold (polished)

gates racing cam belt

gates racing auxillary belt

lexan sparkplug cover

not much of a list but ill get the slowly, be with lee at srd at the end of the year for rebuild.

Hello mate,

I think the main problem with your setup will be revs, the GT42 power will still be climing at 8500rpm and you'll be limited to about 7500rpm with stock valve springs/rods/etc. I reckon with that rear housing size on a std stroke engine you wont be getting full boost until around 5300rpm, makes for a very small powerband, not very nice for a road car. Depends on how much power you want to make though?

Ta

Nice name for your project mate!

PROJECT GOLD RUSH

rebuilt and balanced bottom end with stock head

 

JE pistons/rings

acl bearings

rod bolts

new oil pump

new water pump (toyota)

rod bolts ARP

ARP head studs

engine gasket set (complete) toyota

greddy intake manifold (polished)

gates racing cam belt

gates racing auxillary belt

lexan sparkplug cover

 

 

not much of a list but ill get the slowly, be with lee at srd at the end of the year for rebuild.

paul, on your bw turbo kit i spoke to you about when will the power come in at full boost? what revs roughly?

If I reduce the size of the A/R to 1.01 Paul what sort of difference would I see to full boost within the rev range.

Nice name for your project mate!

cheers mate, looking forward to cracking on now, every nut and bolt is being gold plated ha ha, i have to do it now as life is too short and plus i cant have hodge winning every show lol i can happily come second.... until yours hits the scene too

Hodge what's the idea your saying,increase the power more progressively to reduce stress on the engine?

Just the idea I was getting from supraforums Dave. Instead of all the power coming in all in 1 huge rush with a fast spooling turbo a bigger more laggy turbo will spool slower hence less sudden impact on the engine, well in theory.

Have you done anything with the head other than cams?

theory sounds good to me but aint that the point of having twins, i thought people go single for that impact of sudden power which pins you in the seat

Just the idea I was getting from supraforums Dave. Instead of all the power coming in all in 1 huge rush with a fast spooling turbo a bigger more laggy turbo will spool slower hence less sudden impact on the engine, well in theory.

Makes sense,someone like cw or jagman would probably be better to comment than me though

Have you done anything with the head other than cams?

I've ported and polished it Jamie. Next I'll be fitting some titanium springs and retainers but will be leaving the stock valves.

I've ported and polished it Jamie. Next I'll be fitting some titanium springs and retainers but will be leaving the stock valves.

Id go dual valve springs then up the rev limit to something like 7800-7900 should be plenty of revs for that turbo.

I made the mistake of going single supertech valve springs in my last build and we think i was getting valve flutter, my power stopped dead at about 6500rpm where it should still have been climbing fast to my 8200rpm rev limit, running a to light a spring on a big turbo/big rev 2jz wont let the bucket follow the profile and performance is compromised.

http://i30.photobucket.com/albums/c338/jamie450x/894bhp002.jpg

Its all being changed now and if my power keeps rising this time as it should i hope to hit the 1000bhp mark with ease.