timewellnick

As some of you may have seen, I am currently re-building my sierra (its in the restoration forum).

The engine was re-built by harvey gibbs about 4 years ago and really is tight as a drum and quiet as a mouse.

I have tried to spec the car to stage three so far but I don't know much about tuning etc so I may have missed something.

It has :
044 pump and upgraded loom
rs500 intercooler and larger radiator
group a coil
dark green 803 injectors
3 bar map sensor

The rest of it is standard as far as I know. It is a green top engine and has a sensor in the exhaust by the turbo (no idea what it is lol).

Ideally I would like around 350bhp, the only thing I can see holding it back is the turbo which is a standard t3, what turbo would you go for?


Also if anyone has a facelift dash heater vent contol hanging around, I am desperate for one!!!!

timewellnick

Forgot to say, it has a 3" stainless exhaust all the way through, but with only one box, so it sounds awesome!

Jay,

iTrader: (4)

First thing things i did was gearbox and brakes aa the gearboxs break very easily and the brakes are crap then find more power mate

Caddyshack

Same as jay, sort the box, better intercooler, good mapping, 3.9 diffs, efr turbo...the coil on plug with new ecu...in that Oder IMO....then 6 degree rear beam. Close ratio oppliger box works well on road but not cheap.

Jay,

iTrader: (4)

The boxes are weak as hell

Jay,

iTrader: (4)

Oh rob a bank lol forgot to mention that lol

Caddyshack

I thought sapphires were meant for ram raiding....to pay for mods?

timewellnick

Haha yeah I reckon I may have to rob a bank soon!

I have had the box checked over and had new bearings, seals and they put in new syncros aswell, so I will keep that box until it blows. What sort of power do they seem to take?

The thing is with the brakes is I want to keep the standard wheels, so I guess that doesn't give much option with upgrading them?

Caddyshack

You can get bigger brakes and better pads under there, speak to Reyland.

The boxes fail close to,400 lbft of torque, the lower they make the power, the earlier they fail.

Marc sierra

iTrader: (1)

I guess it depends what you want from it. I like to take mine to the track once in a while and there I find that the power is fine. It currently has a T34.48 with 55lb Siemens injectors, so should be good for 360/370 bhp. But on the track I am running it only on 1 bar boost in order not to kill the (standard) gearbox. I guess at 1 bar it is about 300 bhp but on the track I find the handling and braking much more important (and also more fun). Therefore I did already upgrade to a 6 degree rear beam and 320 mm front discs with standard calipers. Currently I'm upgrading the brakes to even bigger, 356 mm with four pot calipers.

Upgrading the gearbox is on my list somewhere, but I'd rather have a set of decent coilovers first. In the end it all depends on your budget.

Caddyshack

Marc, how different did you fine the car on the 6 degree beam?

I found track day tyres gave huge improvements once the suspension was right on my track car, it also meant I preserved my road tyres.

Marc sierra

iTrader: (1)

Before I had the 6 degree rear beam it had some slight play in the bearings of the rear arms, but not that much. And I don't know how the wheel alignment was at the time. But on the track it understeered very badly in the slow corners. Probably also in the faster corners, but I didn't enter them on the limit. With the 6 degree rear beam the understeer is gone. When I now turn into the corner the front just grips perfectly! It is on Koni's and fastroad Ahmed springs and I changed the 18 mm rear arb for a 20 mm arb and now the handling is very neutral. I did have a 21 rear arb with rose joints fitted, but it gave the car a bit snap oversteer which I didn't like, so I then changed to the 20 mm one.


In the video (~6.35) you can see the rear starts to slide mid corner, but it was very easily correctable. For that reason I just let it slide a bit before correcting it. But with the 21 mm arb I nearly spun, it fishtailed 3 times before getting it back. Unfortunately I don't have that on video.

Caddyshack

Cool, thanks for posting. Really looking forward to getting my 6 degree on there, still got to work out how to get the bladed arb on the rear but the car doesn't have one now on the standard setup. I have a bladed front to go on there too.

costina

iTrader: (1)

You will need a T34.48 turbo to reach 350bhp which you can get on greens at a push. I have seen 360bhp on greens with no room for error.

55lbs would be better if you can get them which can produce upto around 430bhp depending on turbo spec and mapping boost etc.

The best advise is choose a tuner and go with their recomendations.
I will save time and money and a head full of confusion.

Paul

1374lee

iTrader: (11)

Indeed Paul, 100% agree with that, a head full of confussion for sure..lol.
T34 with .48 ex housing Nick would be perfect.


CheeRS.Lee.

Jay,

iTrader: (4)

A t34.48 would damage the box easier than a t34.63

costina

iTrader: (1)

Oh yeah torque the biggest killer.

Forum advice is fine but i cannot stress enough about choosing a tuner and sticking with thier ideas.

1374lee

iTrader: (11)

Yes I forgot we are talking 4wd and the chocolate g/box..lol. As said torque low down will kill the 4wd box sooner rather than later.

CheeRS.Lee.

Caddyshack

I have said it before on here, as I left MAD, Mark said to me "with the torque that is making you had better get an Oppliger on order", it didn't make 300 miles.....on low boost

turbotrev

You have over 100hp and 100lbft more torque than the op wants though.....

Cheers Paul

Caddyshack

I was just telling a story, nothing more or less BUT on low boost it was about 400 lbft of torque and 414 bhp so prob not far off.

timewellnick

I have had a look online, but where is the best place to buy a t34? I can't find any anywhere! So you have .48, .55 and .63 correct?

What I may do is get it set up and running with the standard turbo first then gather bits to go a bit bigger power.

Marc sierra

iTrader: (1)

Yes there is a .48, .55 and .63 exhaust housing. I ordered mine from CR Turbos last year. I ordered it without the exhaust housing as I just used the original .48 housing from the T3 that I took off.

Jay,

iTrader: (4)

I think Vince Osborne can still get a t34 but there not cheap as there not produced much these days 01425 543303

1374lee

iTrader: (11)

As Jay states above Nick, give Vince at Turbo Performance a call.

CheeRS.Lee.