View Full Version : Any tips for a little more bhp/torque?

14th August 2000, 22:41

First of all I must say how impressed I am with 22b.com. The various sections are laid out particularly well thus making it very easy to navigate.
Secondly I am also impressed by the quality of information in this Cosworth section and the Cosworth FAQ.

The reason for my post is that my tuning knowledge is not great nor is my budget. The tuning tips that I've read on here are excellent but are some way out of my reach at the moment.

My car is a 2WD Sapphire with a 270bhp chip. It has an after market exhaust and filter. Everything else is standard.

My boost gauge on acceleration reads 21psi upto about 4750rpms then backs off to 14psi, is this normal/safe for a 270bhp chip and a standard T3 turbo/yellow injectors?

My CO is 3.5 percent.

I am now used to this power/torque and would like a bit more.

Would an uprated intercooler make a difference?

Would light green injectors help the fueling?

Do I need a 3 bar map sensor?

Apologies in advance for my naivety on this subject but we all have to start somewhere don't we http://bbs.22b.com/ubb/smile.gif!

[This message has been edited by CC (edited 14 August 2000).]

15th August 2000, 13:06

Glad you are finding this BBS informative, especially the Cosworth section http://bbs.22b.com/ubb/smile.gif

Right down to your questions!

If you are running a 270bhp chip (based on your boost guage readings), I would say that a peak of 21psi is ?. I would expect you to be holding somewhere around 15/16psi. The fact that you are backing off to 14psi, sounds about right, but is too early on in the rev range. This could also indicate a problem. This could be a number of things including a knackered actuator (Is it a -31?/I dont think a standard one can hold 21psi), you could be hitting the boost limit or the charge temp is too much on your cooling system - amongst others.

I hope you mean your CO is 3.5% on idle........If it's that on run, you better get it checked out NOW!!!

From what I know, an uprated intercooler on your model will help tremendously (apparently an inherent problem on sierras - Except the RS500 http://bbs.22b.com/ubb/wink.gif).

Uprating the injectors are only required if you are looking at changing the ECU program. For your present chip, they are not required.

Same goes for the 3 bar map sensor, not needed until you go to future levels.

If I was you I would take you car to a reputable cosworth rolling roader. Get him to check your boost and fueling, just to be on the safe side. If your boost figures are right, they need adjusting immediatley!!!!

For the next level you need the following:-

4 x Green injectors - 803's
3 bar map sensor
-31 actuator
Stainless exhaust from turbo back
new chip

This conversion would give you upto 330bhp and bags more torque. I personally would not go any higher, then this with your engine. As unfortunatley your block is made of chocolate!!!! (Needs a 4x4 one!!!!)


Anymore for anymore (waiting for John or Mike to correct me!!!!!) http://bbs.22b.com/ubb/biggrin.gif

[This message has been edited by shaunee (edited 15 August 2000).]

15th August 2000, 20:21
According to the RSOC....no, I won't bother. http://bbs.22b.com/ubb/wink.gif


15th August 2000, 22:38
Shaun, my mistake, the car does boost to 21psi (do you think this is too high for a 270bhp chip?) but it backs off later, at about 5500rpms...is this backing off in boost normal for chipped car in your opinion? LOL, yes the 3.5 CO is at idle, thank god!

Thats one of the main reasons i posted cos I'm considering a new intercooler and wondered what effects it would have without changing anything else on the car.
I do have a -31 actuator.

Why a stainless exhaust from turbo manifold? The exhaust i have on it now is a 'mild' stainless 3" pipe all the way through. But i've seen Cossies with bigger downpipes?

Yes I will get it rolling roaded soon and set up properly, but before i do that I'd like to put any simple mods on it beforehand so that it can be set up as a whole - if u get my my meaning!

What intercooler would best suit my set-up/budget?

Yes I've read the 2WD doesn't have the best bottom
end, unless you're talking about the 2WD RS500!

Thanks for your help.

PS Stef come on spit it out!

Mike Rainbird
17th August 2000, 07:42
Turn the boost down quick, or suffer the consequences! The injectors cannot cope with that kind of boost and the engine will be running lean, which may cause a major melt-down or at the very least the det will be slowly eating away at the head / tops of the pistons!

You obviously either have an aftermarket actuator or the settings on the amal valve are way out! What you should be aiming for is a spike of 17-18 holding a constant 14-15psi. Any more than this is may cause damage.

An uprated intercooler would cool the charge air and is worth another 10-15bhp if you are using the standard 2wd item. A good cheap upgrade is to use the 4x4 one which is much larger. The problem with this is that due to its increased efficeciency, the boost will rise even more by 2-3 psi and will need to be turned down to compensate.

Light green injectors are only a few more percent up on the standard ones, but would definitely help if you are insistant on leaving the boost settings as they are....

You do not need a 3 bar MAP sensor unless you are running more than 15psi constant held boost. This is required when you switch to dark green injectors, as you would then be running 21psi of boost with the standard turbo to get 300ish bhp.

The 2wd block is more than adequate for up to 350bhp, and after that only needs replacing when it cracks (which it will do when running big boost http://bbs.22b.com/ubb/wink.gif).

I also hope you are running super-unleaded fuel. If not, you are probably too late in preventing any damage anyway.....
Mike R
Norfolk Group RSOC Chairman www.rsnorfolk.co.uk (http://www.rsnorfolk.co.uk)

17th August 2000, 17:38
Thanks for the advice http://bbs.22b.com/ubb/smile.gif

I changed to SUL when leaded was no longer available and have used it since.

I've heard of 'octane boosters', does have anyone have any opinions on the function/necessity of these?

I thought 21psi was a bit much. I vaguely remember, not longer after I'd bought the car, a supposed 'Cosworth specialist' messed around with the amal valve in order to give more boost, and I've thought nothing of it since....maybe this is the reason for the high boost?

How I am best decreasing the spike, by adjusting the actuator myself or shall I best leave it to a tuner (obviously not the same one!)?

I understand the gains involved in an uprated intercooler ie as in decreasing the charge temp. But as u say, this will increase the psi, so again I will be running too much boost for yellow injectors, so I'll have to reduce the boost, losing the possible 10-15bhp gains in the process...isn't this catch 22!?

Again sorry if i'm way off the mark here as I'm only just becoming interested in tuning etc.


17th August 2000, 19:23
See, Mike & I nearly agreed!!!! http://bbs.22b.com/ubb/wink.gif

IMHO, if a car is set-up right, by a reputable tuner, you shouldnt need to run on Octane Boosters. The only time I would consider in using this (I am assuming any car I run is set-up correctly), is down Santa Pod or on a Track day. If the chip and set-up is correct, there is no reason to use it!!!

Adjusting your own boost.....

Are you competant?
Do U know what you are doing?
Are you sure your boost gauge is accurate?

If you cant answer positively to ALL of the above, leave it to a professional!!!

If you want to email me, i'm sure between me Mike & John, we can suggest RELIABLE tuners near to your location.

Mike's on about HP gains on your proper boost settings! So it's very relative. From my limited past experience, better cooling doesnt give you more power over your conversion target (well not in the case of uprating to a different intercooler), e.g. 270bhp (Mike's bound to shoot me down in flames!!! http://bbs.22b.com/ubb/wink.gif). It will just give you a better chance of achieving this target. IMHO rarely do stated conversion BHP's get reached! There's alot of BULLSH!T out there!


P.S. Not that this is very conclusive, but what colour is the inside of your tailpipe. If it's not black.........you better get your wallet out http://bbs.22b.com/ubb/wink.gif
[This message has been edited by shaunee (edited 17 August 2000).]

[This message has been edited by shaunee (edited 17 August 2000).]

Mike Rainbird
18th August 2000, 08:05
I would personally steer clear of octane boosters and instead have the car set up safely to run on the current 97 RON fuel. This is because I have heard of octane boosters increasing the heat inside the engine and causing more problems than they solve.

If you reduced the "spike" boost on the actuator, you would also reduce the held boost as well. As 14psi is spot on for the held boost, you only need to reduce the spike and would have to do this by re-jetting the amal valve.

The gains from the intercooler are purely down to the more dense charge air that the bigger intercooler could provide. As an engine is just basically an air handling unit - i.e. the more air you get in (and providing it is matched by a corresponding amount of fuel), then the more power you get out of it. Accordingly, a larger intercooler can provide a more dense charge air at any given boost pressure, over your standard one.

For your information I have a second hand Pace RS500 item for sale for 150 (as I needed one with a bigger inlet as I have just put a T4 on mine)....
Best regards
Mike R

18th August 2000, 17:41
Mike I've heard/read bad things about the effectiveness of pace items (to do with the core i think)....no if u had a 4x4 for less than a oner...lol!

Shaun the answer is no, no, and no! so I think a trip to a decent tuner in the North West is on the cards, any suggestions?

My exhaust isn't black...

Thx again.

20th August 2000, 02:21

If it's white/grey/light brownish, it's running MEGA lean.......if that's the case, get it sorted ASAP!!!!!!!!


20th August 2000, 12:36
Sorry shaun, i meant that the exhaust tailpipe is black...it is 3.5 CO at idle which is ok i think but I'm actively looking to get it rolling roaded b4 the end of the month.

With regards to the Pace intercooler, before i upset anyone, i'm not saying there is anything wrong with them as i've never owned one, they maybe fantastic for all i know and the little snippet i'm quoting could well be wrong...

Mike Rainbird
20th August 2000, 16:09
I also have a 4x4 intercooler sitting in the loft - yours for 100.... http://bbs.22b.com/ubb/biggrin.gif
Best regards
Mike R
PS I have a Pace RS500 intercooler on mine and have no complaints.....
PPS If you are interested, I won't be able to respond, as I go on holiday tonight for two weeks.....

[This message has been edited by Mike Rainbird (edited 20 August 2000).]

20th August 2000, 16:36

[This message has been edited by CC (edited 23 August 2000).]

Mike Rainbird
5th September 2000, 12:22
I take it you are not interested?
Best regards

6th September 2000, 17:34
sorry mike i bought one when you were looking at the pyramids....couldn't wait as i wanted it for a track day on the 30th Aug which was cancelled anyway...........pain to fit too, had to shave off the top of my rad, if i need owt else i know your the man to ask.

Mike Rainbird
7th September 2000, 08:46
No worries, sold it an hour later anyway! http://bbs.22b.com/ubb/biggrin.gif

Can't believe you shaved the radiator! It only needs a couple of spacers to drop it down and Bob's your mother's brother...

Live and learn...
Mike R

7th September 2000, 14:10
hehehehe http://bbs.22b.com/ubb/biggrin.gif

sorry, shouldn't laugh http://bbs.22b.com/ubb/biggrin.gif http://bbs.22b.com/ubb/biggrin.gif

If in doubt, ask http://bbs.22b.com/ubb/wink.gif

The gurues are here http://bbs.22b.com/ubb/wink.gif LOL

7th September 2000, 18:03
DOH!!!....silly me http://bbs.22b.com/ubb/biggrin.gif, my knuckles looked like I'd been punching bricks lol! God knows how an RS500 jobbie would fit in there!

Differences? It seems to hold boost a little longer I think.

All part of the experience I suppose but next time I will ask!

7th September 2000, 18:25

What, all 21 psi of it http://bbs.22b.com/ubb/biggrin.gif http://bbs.22b.com/ubb/biggrin.gif.......on a stage 1 chip http://bbs.22b.com/ubb/tongue.gif


[This message has been edited by shaunee (edited 07 September 2000).]

7th September 2000, 19:29
So chris you want bhp and torque - Simply fit a button.

Click..........................and your gone! http://bbs.22b.com/ubb/biggrin.gif

Gone in 60secs - more like 2secs and one gear change! http://bbs.22b.com/ubb/biggrin.gif


7th September 2000, 20:52
Shaunee - yes 21psi!!! Bit worrying really, as I only have yellows......I'm sure it's something to do with my amal valve being fiddled with? At the risk of sounding daft (cos i am http://bbs.22b.com/ubb/biggrin.gif), surely the standard MAP sensor would stop it holding 21psi right the way through??.....

Then again my gauge could be wrong.........I dunno cars eh http://bbs.22b.com/ubb/biggrin.gif?

Martin - I don't know about anyone else but i had NO idea whatsoever http://bbs.22b.com/ubb/biggrin.gif. Fookin great! I gather you're not using it at the mo', is it still in your car? Do you know what bhp your car was when the NO was on? Do tell http://bbs.22b.com/ubb/smile.gif.

7th September 2000, 21:03
Of course its still rigged up and will be until it blows the engine skyhigh!!! http://bbs.22b.com/ubb/biggrin.gif
Still to turn it up and find its limitations - we also have some trick ideas to use it better.
Right now its basically adding 50+bhp across the whole rev range. Makes it good in the wet! http://bbs.22b.com/ubb/biggrin.gif
My car holds over 15psi and has the standard map sensor. http://bbs.22b.com/ubb/smile.gif

7th September 2000, 22:11
Come on what have you done to it you winder-upper http://bbs.22b.com/ubb/biggrin.gif?

If mine is 21psi what peak bhp do you reckon it might be, just a guess?

7th September 2000, 22:26
If your still running yellows and it holds 21psi at the top I would say both your engine and your turbo are going to come down to earth with a bang! http://bbs.22b.com/ubb/frown.gif Has anyone properly checked the fueling for you - especially at the top end? I'm not trying to annoy you, just dont want you to damage anything.
Get it sorted by someone that knows what their up to, us stage 1 boys need to stick together! http://bbs.22b.com/ubb/smile.gif
I could show you a picture under the bonnet but I'm scared you would copy it and damage your engine just as I've yet to prove the reliability of nitrous! Main reason for doing it is I'm hoping to blow my engine up so that I am motivated to get the "REAL" engine so that I can get some real power. http://bbs.22b.com/ubb/biggrin.gif But in saying that the nitrous has been properly setup - only see the H/gasket as a weak point at the moment. http://bbs.22b.com/ubb/smile.gif
Have however come up with a crazy plan for the most powerful stage1 you'll ever see - big cossies better watch out! And I do actually mean this for real!

7th September 2000, 22:37
the thing is martin it's been like this now for 2 1/2 years with no major probs, on the same h/gasket, i dunno, maybe the gauge is inaccurate. It doesn't hold 21psi right to the top, it does back off to about 14 or 15 psi whereas b4 my amal valve was played with it peaked at about 16 and dropped off to 14psi.....

It does seem very quick to me, and i would have found just how quick it was if it wasn't for that PF fiasco. But I've never been in a big BHP Cossie so I've nothing to compare it with.

I really need to get it sorted on a r.r. instead of wasting my money on daft stuff!

No doubt you'll keep your plans a secret http://bbs.22b.com/ubb/smile.gif but have you seen that RS500 engine going for 2.5k? Nice!

i reckon you're gonna fit two engines!? Or twin turbo a V6 Cosworth lump!

7th September 2000, 23:25
If it backs off it shouldn't be too bad - especially if its lasted that long - must be pretty good http://bbs.22b.com/ubb/smile.gif

Bollix - you second guess was pretty good! http://bbs.22b.com/ubb/smile.gif Need to wait and see what happens.


7th September 2000, 23:51
Wow you get around you do http://bbs.22b.com/ubb/wink.gif http://bbs.22b.com/ubb/biggrin.gif.

Hey I'm not so daft am I?.....am I http://bbs.22b.com/ubb/biggrin.gif?

I remember reading something about the bloke who owned Turbo Technics, he races a Sierra V6 Cosworth with twin Turbos. Supposedly had 600bhp at about 1.5 bar or something!!! Be great if you could do it, I expect the engine isn't too light though?

8th September 2000, 00:05
I'll just lighten the rest of the car to make up for the weight! The people that are doing the conversion have seen Geoff Kershaws car in the flesh( one your talking about) and reckon they can better it so.........Yeehaa!!! If theres a problem with the weight how come he is successful with his? A way of getting round this is to move the engine back to try to get a weight balance so that it doesnt have as much influence.
It'll have 14 injectors by the time I've finished with it and the engines already sitting on the workshop floor. http://bbs.22b.com/ubb/biggrin.gif
Still havent decided if its happening or not as I need to get a job, could happen soon after though. http://bbs.22b.com/ubb/wink.gif

8th September 2000, 00:22
NUTTER lol http://bbs.22b.com/ubb/biggrin.gif! Yes I see what you mean about weight, his car is supposed to be really competitive etc....

When you do get some serious money coming in, which you will, will you stick with the Sapph......I've gotta admit, even though i love my car to bits, when I've graduated I reckon I'll go for something newer if poss.....but then again I'm admittedly crap with mechanics so tuning isn't really an option for me http://bbs.22b.com/ubb/frown.gif