Hey guys, will be starting a new engine build soon as have destroyed my 205block...

After some opinions on what would be the best way to optimise/get the most out of my old T4 snail?

Will be having a new 200 bottom end(a well seasoned block with 6 long studs) with virgin crank and bores etc etc.

My head is 26/25mm and have all other bits to support 500+bhp.

So what I was wondering is.... What cams and comp ratio would you run and how much boost can a T4 reliably handle?

(I also have a direct port nitrous kit and my ECU can be mapped for control of this as well )

Please no T4 vs GT stuff here as I'd rather not splash out for external gate just yet

All opinions welcome!

 

16/14 16/std cam choices

A 16/14 will give best power and the 16/std will give a little more drivability but loose 25bhp up top

They will have 32 psi everywhere and do it all the time, super reliable

Standard or slightly lower compression IMO

 

I've heard of one. With 44psi up it arse.

 

Thanks Jimbo, exactly the kind of informed reply I was hoping for

Mat, I've heard of this as well! Must be uncontrollable!
Well, it would be for me anyhows..

 

7.2:1 compression ratio

 

Is that what you run Gareth?

 

Moanstone needs to know as well

Steve

 

He just needs a proper map doesn't he?

 

And another 200 Block as his cracked

Steve

 

max out a T4?

just weld the wastegate shut

 

Gutted

 

wonder what it'd boost to before everything goes pop

 

Jim knows his stuff they just built me a 550hp RS500 engine

 

Sounds good that Luke

I don't know the differences between your T4 and my turbo but my engine was spec'd for the GT - 200, 6 stud, 7:5:1, BD16/08, 26.5mm head and i would say between 2.5 & 2.75 bar will run through it

 

No but it's a classic spec, driven a few are they are great

 

I'm well aware mate

It should be fun Chris!

I think the 3076 flows a bit more than a RS500T4 (although mine is tweeked a bit )
Dude your car is going to be monstrous with that kind of boost! Have you had your rods peened or anything?

Interesting, I'm just wondering if it would compromise response a little compared to 8:1 or 7.8:1 etc. Thanks for the input

 

Not sure the GT has the legs the T4 has. 2 cars off here M.A.D mapped had this blower and made 500 & 501 but i don't know what boost but both were running Autronic

I never had the rods peened as i didn't think i would be entering that level of power but my complete internals were balanced and a few other things as i don't see it making much more than 500 if it gets there - time will tell

As for C/R - i'm no mapper and only pick up little bit's i read on here and i'm sure i read somewhere that higher comp requires more ignition in the map making things hotter - please if i'm wrong or have the wrong end of the stick correct me

 

what happened to the bottome end mate? too much right foot?!

Any new pics of the old shed??

Hope you're well.

 

Contrary to above I always thought the opposite, I would think lower compression would allow you to add more ignition not less as you stand less chance of det, just like you this is what I have picked up, it would be good if someone who knows could confirm out of interest?

From what I understand, it used to be the done thing, everyone dropped compression which meant driveabilty suffered, but nowadays perhaps it with advances in mapping since the early days, this thankfully is why it isn't done on your averege spec car now?

Martin

 

Interesting mate.. I always thought that the 3076 was a 540/550bhp turbo?? Whatever it makes mate it'll be very special!

Hi Rich, I'm very well thank you mate

Its a long story.. Basically I finished putting the new setup together, we took it to the rollers for mapping in october and had all sorts of teething trouble.. (I'd bought a second hand coilpack and it started to miss badly as soon as it got hot) we were half way through mapping and posted some half decent(ish) figures:

(please excuse shitty phone pics.)









Then just as we were putting some ignition in the map the billet fuel rail spat an injector out and fuel vapour everywhere! Luckily no flames but a very close call!
Here she is outside the rolling road...



BayNeeds a clean in this pic!)



Back to the story...
Roll on a few weeks and we spaced out the injectors with some washers and I bought a new coilpack for her.. We went out to do some more mapping on the road and to check all was good before returning to the rollers. The car was fooking flying! (She's got a 3.9 diff now as well)

The next day I get a call from my mate Jez who does the mapping to say that there is a massive pool of coolant under the car in his workshop.. He put the car on the ramp to see where it was coming from to find the block properly cracked down the side

Hence new bottom end needed!

Some other pics you may have seen...



(Front end raised up to get her on the lorry )










Back when the wheels were anthracite:




There you go mate, I will do that resto thread soon so you can see what Ive been up to.. Probably when the new engine starts coming together

She's changed in a few places since you had her.. Spot the difference?
Can only apologise for stripping her out btw...



Hope you are keeping well mate

 

The compressor maps for a t4 and a gt3076 show that the g3076 should make much more power than the t4, it flows something like 6lb of air more on the compressor map.

But, due to the exhaust wheel they will make pretty well identical power to a t4 at the same boost, maybe 5-10 bhp more.

The exhaust wheel of a t4 is big, hence being slightly more laggy, where a gt30 has too small a ex wheel for the compressor wheel but gives good response.

Mat, I've no idea why any body would want to run that boost on a t4, rediculous IMO

Gareth, I wouldn't advise that comp ratio but have driven one at 7.2 and the word for it is raw, very un progressive, awesome feeling but in the real world not good

 

You are correct martin, with higher compression you generally run less ignition.

 

I've never known to feel a difference on a low comp car vs std comp...Euan's old 550bhp, his was 6.2:1 and he swore it drove as well as it did off boost as it did when it was standard


Same as the old "oh huge intercoolers an it'll be laggy/unresponsive"

I never noticed any difference whatesoever when I doubled the size of my apexi intercooler on my 200sx...

Think people jus mump their gums for the sake of it half the time when 9 times out of 10 they've never tested their theory's!

 

What advance in mapping? People think the tuning world has moved on so much, but it really hasn't.

 

Just the current "trend" changes lol

 

if you need a block i have a 200 think its on +25

 

Ive got one lined up thanks mate

 

Still no pics of the cracked block Luke ?

Steve

 

I started to pull the engine out today mate.. Will get some snaps as soon as I can

 

I hope mine don't go the same way

Got the 200 block under the workbench just in case

Will you be doing anything extra on the rebuild ?

Steve

 

Surely it would have gone by now if it was gonna mate?
Gonna have the whole lot balanced, block long studded.. Probably gonna get the rods shot peened and I'm tempted to get some wrc style oil jets if the machining for it isn't too expensive. Then obviously swap the Ab07 out for the new cams. Possibly plumb in the nitrous as well

 

Oh yeah and new pistons hence the comp ratio question

 

No head work ?

Steve

 

Mine is running a t4, 15 inlet, 14 exhaust, 7.2cr, 8 greens etc, bearing in mind that it is purely a road car, would I benefit from changing to a 16 inlet or would it be a backwards step as far as response goes? Also, what gains in bhp/torque would I expect to see?
Karl

 

Your best off speaking to Tony @ Turbosystems

He has a rough idea on engine specs and LOVES T4s

Steve

 

It's funny you should say that because its a turbosystems engine originally (kev sharps old engine) so I assume Tony specced it originally? I assume it was specced for driveability with good power as apposed to ultimate power, it drives really nice even off boost.
Karl

 

Already got 26/25mm ports and cut back guides and was rebuilt by reyland a few thousand miles ago

Will probably need some double valve springs I guess?

 

Steve's block is Playing with him, its waiting for the next Kent rolling road run and its gonna shit its self on the rollers in front of everyone lol

 

Who makes that ab07 inlet cam, that's the one that works fine with standard pistons?

 

Kent cams I believe.

Steve