St170 Engine

[Guest dinger]

As some of you know I am fitting an ST170 engine into my Zero,

 

Now, Originally I was guessing that by adding a set of throttle bodies and stand alone management would see me into the 200bhp club! sadly not, The VVT on the exhaust cam is almost at its limit @170bhp.

With a few hours on the net and a few phone calls to suppliers the outcome was that I'll need to ditch the standard VVT setup and go with new uprated cams,verniers and lifters,(A price is in the post) Power wise with a good set up is 240bhp, with some head work these engines are good for 280bhp without any bottom end work,

 

I am very glad I went with the ST170 engine as future power gains are easily done, Albeit costly,,

 

So my thinking is to replace the cams before IVA, Dunnell reckon it will still get through emmissions with the cams, best start writing my letter to father christmas.

[Longboarder]

You have discovered the trap of the ST170 engine. Promises so much but fails to deliver unless you spend a couple of grand. Cams I can cope with. Finding that the lifters are made to specific sizes like shims but they're not shimmed. Throw in the verniers. A reworked head is a grand. I sold my tuned silvertop for one and have dropped to just 155 at the flywheel. Decent pinto makes that. Standard blacktop on jenveys makes 175. Laugh? I nearly slit my wrists.

Rolling road thursday and with the new exhaust system and the exhaust cam vernier I hope to see more than the 155. We shall see.

 

Nigel

 

Out of interest who are you talking to who believes they can get you 240 bhp?

[Guest gdc]

nigel are you sure you dont have the st 150 ?there was one .

mine is standard as you know and is giving , on a new r/road 187 bhp

the benefit to me over highly tuned pintos and zetecs is that it shouldnt break ,

the crank is steel the rods are steel and the pistons are forged ,that in its self is a major upgrade on a standard engine with rubber cranks ect .dinger you are right that the engine will only give a specific power as standard and the cams are the restriction nigel i bow to you superior knowledge re the lifters , i am more than happy with mine as it is and i dont plan any upgrades on the engine .

well mayby a supercharger ?

nigel please dont blame me i know i talked you into the st realy sorry your not happy with it .

but you wont break it .the reason i have continued with the vvt is that i can drive it like a shopping trolly

through town and when out in the open i can let it go , i dont have to feather the clutch and the throttle whilst in town or road works , it works for me .

graham

[Guest dinger]

Alright Nigel,

 

Unfortuantly using the ST170 engine isnt quite in line with a hoody "do it as cheap as you can" mindset,(which I love)

 

This means that if you want big power its going to cost big bucks, Its always been the way whether you have a skoda or an SLR. Yes, reaching over 200bhp on the ST engine is expensive but its pretty much bullet proof and you'd be looking at 5k for a silertop/blacktop build running 240bhp.

 

I dotn know whetheer you have seen THIS THREAD which has some really good info.

 

Cheers

 

Dave

[Guest gdc]

hi dave good thread but it makes clear what has been said 180 ish is the max on std cams .

my vvt kicks in at 2999 rpm and does give a kick in the arse but as said earlier i want my car to be well behaved arround town so it suits me so i am happy .the ford vvt is vairiable though with proper control not just on and off .

graham

[Longboarder]

Relax Graham. I chose to fit the ST engine, sell the brand new blacktop without fitting it and the tuned silvertop. My choices. The retrospectoscope is a useless instrument. I have read the linked thread. Boy did it take a while for the penny to drop and be accepted. Ford do use pwm continuously variable inlet valve timing. I also note that the cams have yet to be bought and fitted.

Rolling road in the morning and I will post results.

In time I will make the decision to develop the engine, supercharger perhaps or replace.

 

Nigel

[Guest dinger]

Looking forward to seeing the results nigel,

[Guest ianjenn]

I have an st170 with bike carbs and megajolt

with vvt at 2600rpm got 152bhp at wheels. Across the rev range this was 10BHP better than my blacktop and the total cost after selling unneeded bits worked out at about£200 for change from blacktop to st170. So overall I am please I changed. My next step is to fit a nitrous kit. Just waiting on a price from Steve (loopyonion) It mite be worth considering as an option.

[Longboarder]

Found another 13 BHP(168), a small oil leak and melted the 888's. Had to nip home at lunchtime and get the road wheels which have yoko 539's on or the toyos would be all used up. It's raining cats and dogs down here so haven't been able to test if 13 bhp makes a difference but at 20 quid per horse that's good value. Remains very drivable in the traffic going home. No idea how accurate the local dyno is nor the dyno at Mech Motorsport in Cheltenham so that 13 bhp could be more or less. Have to see how it goes next trackday.

Overall I'm happy with the result and the day was good fun. Finally found a local dyno operator who knows what he is doing.

 

Nigel

[Guest gdc]

hi nigel

i realy am starting to think you mayby have the fiesta st 150 engine not the focus 170 engine .

the percentage differance is almost exact , i went from 170 to 187

you poss went from 150 to 168 it has to be a posibility .

you have fitted a venier mine still runs standard vvt .

your ex is far better than the one fitted to my engine by your own experiance .

i did find when i fitted the larger bore ex that the punch when the vvt cut in was a lot less than with the smaller ex manifold . the mapping changed dramaticly also .

mayby you were 20 bhp down to start with .

graham

[Guest dinger]

Rolling roads differ so much, now that you have found a good dyno you can use that figure as a base and work from there, Glad you found some gains but as you say, only a good drive in the dry will tell,

 

The ST150 engine (as I believe) is a true Duratec and differs in so many ways, I'm sure Nigel would of noticed, from memory the sump is totally different and correct me if I'm but didnt think it mated to the type 9 gearbox?

 

Many years ago I came across a similar issue, However it was not as expensive as this subject, But I done some testing on the rollers with 1992 XR2I, K&N claimed their air filter gave bhp gains and worked better with a free flowing exhaust, The car was dyno'd in standard form and then with the air filter and then with the air filter and exhaust, Bhp dropped as did torque,

Fords dont spend millions on development and get poor results, which is why when they do build something hot they usually get it right,

Hence such a good power output on the standard ST170 engine,

 

I'm waffling aguin, lol

[Guest gdc]

so if the st is a zetec with a trick head and good internals , and bearing in mind the shim deal being a pain .

could a silver or black top head be fitted to the st ?if wrong about the st 150 i hold my head in shame !

 

graham

[Guest dinger]

so if the st is a zetec with a trick head and good internals , and bearing in mind the shim deal being a pain .

could a silver or black top head be fitted to the st ?if wrong about the st 150 i hold my head in shame !

 

graham

 

 

There is no reason why it couldnt Graham, Pointless though as you would spend a grand getting it to the same spec as the ST170 head, Remember the ST has huge ports and bigger valves. Then you would still need better cams,

I had an email back from "catcams" and I quote.

 

Hi,

 

Yes we have steel billet camshafts that eliminate the VVT.

 

The 2301013 profile will produce 200bhp on a std engine with Tb's and is ideal as it keep the std springs, retainers and fit on std pistons.

 

Prices are:

 

2301013 Camshafts 547.93 + Vat

CTFO170 True Lock Vernier Pulleys £219.54 + Vat/Pair.

 

Regards

 

Matthew Saville

 

 

Catcams N.V.

UK Sales & Technical Representative

www.catcams.co.uk

 

 

Now the question is,,,,,, Is it worth a grand for 30 horses? and thats if you do the work yourself,

 

 

Average price for a blacktop = £200

Bottom end and head work to hit 200bhp = 5k?

 

Average price for St170 = £500

Cams etc to hit 200BHP = £1000

 

I'm just speculating but I know where my money would be,,,, and is,

[Guest woolly]

if it makes a difference to the thread Nigel's 168 was at the wheels just in case there is confusion

 

woolly

[Longboarder]

Just been searching the interwebby for st150 engines and they look like a proper duratec to me. So mine is an ST170 zetec.

The most obvious thing today on the rolling road was the excellent power curve up to 5000rpm. Then it just flattened out till 6300 or so and then dropped away fast. Retarding the cam at high revs as was suggested by Kent lost 30 horses instantly. The feeling from the RR operator was that cam timing was not optimal when fully advanced. After all Ford keep it truly variable and don't use the full 30 degree advance at full throttle. More like 20 degrees over 5500 but closer to 25-30 degrees at full throttle between 3-5000rpm. So it would seem that running full retard up to 3000rpm is OK, 30degree advance from 3000 to 5000 is OK but then you need to back off to 20 degree advance from 5000rpm up. This the omex software can't do so there is power going begging at the top end. Seems like you need a better ECU such as the DTA S60 that can manage P.W.M. cam control to release the top end.

An alternative compromise would be to find/make a vernier to replace the VVT gear without changing the cam as a simple/cheap first step in tuning. Anyone know of such a thing? Could set it up to give a fixed 20 degrees of cam advance and then swing a bit to release the top end. You may loose some power lower in the rev range.

I must be brave and remove the inlet cam wheel and VVT gubbins and see what the front end of the cam looks like. You never know. Might be standard zetec with two added oil passageways!

 

Nigel