forged rods ? needed or not ?

[barwell1992]

Hi, im thinking about doing a VTS engine build, what im wanting to know is if im running high comp pistons, should i go forged rods ? worth the cash ? not sure on the rest of the spec yet but wont be to extreme as i wont have that much cash

any advice would be good, also what sort of bhp figure could i see from higher comp pistons,throttle bodies and clean up of the head ports,fast road cam and then the usual other performance mods

cheers

[blackie_2k5]

as always budget is the deciding factor when throwing money in

its argued if power hunting that turbo is better on budget...its true...but it depends which route you want to take


if looking to go n/a your looking for the expensive route...you can get 160bhp+ with cams and bodies

if wanting to go more then it costs alot...if you're going high comp youll need a decent cam spec(or there's no point in doing it)...if looking for more power again you need a wilder cam...rods.... solid lifters etc which is more money again..as well as head/valve work)

some just run pistons and get +/- 170? but i always see that as pointless? its like me running pistons or rods and not the others? if ones fails youve wasted money???

some do bodies that run rods and pocket pistons to achieve high comp to get 170-180 but even so it still alot of money

so you need a budget lol

(im waiting for abuse from the n/a lads on this one) but as ive always seen it..and what ive picked up along the way..thats how i see it)

[Ryan]

Some people prefer an NA engine and don't want to just bolt on a blower, it's a never ending argument.

Anyway back to the ops question, rods are not needed if not going too wild. It's all down to the spec you plan to run and the budget.

You can get decent power now on the wilder cam profiles that are still hydraulic grind, much more is known about these engines than say 5 years ago.

Budget for the ecu/cams/bodies etc.. Isn't the many thousands it used to be. Not with the predator and sandy brown/Colin satchel tb set up.

[axsaxoman]

max rpm is what will decide need for forged rods in an N/A set-up --nothing else.

yes you need to either pick the bhp+ type of usage the car will get
EG will it need to be road legal +pass a REAL mot ,or is it a track car

Or you decide a budget

then talk to people who have enough experinence to give a reasoned views ,based on experience on the way to get most Bang for your buck .
do not spend any money with anybody until you have fixed goals --
If its going to be an on going project ,then it is even more important to know the final goal so you only buy things in the right order to save extra expense and work further dwon the line

[barwell1992]

At the moment its going to be a pure road car, needs to do ok mpg , I don't really like the complexity of turbo chargin , and the engine I have my eye on need to be stripped right down any way as it knocks, I'm only looking for around 150-160bhp and want it to be very drivable

Also what's the best route with management my car us a 3 plug at the moment would it be worth going for a single plug conversion or should i just run a piggy back ecu on the 3 plug

And I would like the car to pass a legit mot

Budget wise about 2-3k as this is going to be a long project as I don't have that much cash due to running bike nd car and modding them at the same time lol

[jeffchiz]

for 150-160bhp you wont need rods

as said its all down to how high revvign the car will be im quite happy to go to 7800rpm on std rods

ive got 155bhp (hopefully clsoer to 160 when my new bottom end is on as mine was dyno'd with damaged piston rings), my spec isnt massive at all just 708's, jenveys and predator ecu

i was looking in to some cat cams that were about the same spec as ph5's i was told just arp bolts and high comp/pocketed pistons would be needed to achieve around 190bhp and std rods would easily cope with it

[Tom5190]

You need two things before you start trying to make any sort of parts list, you need a desired power/torque and a budget. For 160hp N/A you can leave the bottom end standard.

3K would get you 165hp +/- in terms of parts, labour im not sure.

Also as jeff said above you can see 190hp N/A on standard rods.

[blackie_2k5]

On the standard engine and pocket pistons route

How long do they last like this? I've seen a few around now and it always makes me thing it won't last?

It always makes me think why when I see it? By the time you pay for the machining on the pistons you may as well buy a new/second hand set of high comps?

[Tom5190]

Well i know of one first hand that made around 195hp the pistons are high comp but standard rods and hydro followers. Been running about 2 years iirc.

I wouldnt bother pocketing pistons like you say i think its a waste of time & money.

[welshpug]

as long as they haven't gone too deep they'll last just fine, I had the pistons in my XU10J4RS pocketed 6-8k miles ago and not had any issues at all.

It cost me £90, but the guy is only setup for the XU engine, Colin Satchell can do the TU ones for Sandy and I think htey charge £150, as long as your compression remains high enough for your cam choice it'll work ok.

a lot less than £600 for pistons (I wouldn't buy the cheaper ones if oyu want a 100% reliable engine)

[axsaxoman]

taking into account all you have said then i suggest the following
predator 3 plug ecu --fits directly onto std wiring loom £700?
thats the first thing to buy as all other mods -even if you decide to go boost s/c or turbo or t/bodies it can handle .
as for your target bhp then my ultimate road cams will fulfill exactly what you are wanting £200+vat=£240
160bhp with single t/body is pushing it really with cams that can make it idle happy and pass an mot . It is possible but that would mean lifting the head to do work
to get to 160-170 you really need t/bodies and then you will have what you want with no internal mods.
so ecu £700 t/bodies £900.cams £240, new lifters £192+fpr =£2092
If you want to do it bits ,then cams+lifters +fpr could be first step .then ecu +t/bodies
ring me to discuss in more depth your options

[barwell1992]

All the work would be done my self as far as the engine is concerned , I have a lot of equipment at my disposal as my work used to be a Machine shop for jordans f1

Didn't think there was a pred 3 plug ? , but cool thank for the help I dont even have the engine yet so won't start planning until I get it apart ect

So what does this spec sound like then

High comp pistons and rings
Fast road cam or more extream with pulleys
Solid lifters and uprated springs
Multi throttlebodies
Ped ecu
Smooth inlet and exhaust ports
Service head lap valves ect

And get someone eles to do the wiring lol :-p

What about fuel supply, fpr uprated pump ?

[jeffchiz]

So your going for power than 160bhp then? Don't forget some arp bolts they are a good £100 for 8 bolts :o expensive little fuckers

[welshpug]

arp? pfft, Carillo :)

[Beaniemoo]

I have to admit if strongly recommend rods!
Check out the first page of my rallye build thread to see what can happen without lol

[jeffchiz]

was that down to std rods not coping or worn rods?

[Ross]

Think John said elsewhere - rods are dependant on rpm not power. Standard rods with ARP bolts are strong as an Ox, but I'd not want to give them silly revs.

[barwell1992]

So your going for power than 160bhp then? Don't forget some arp bolts they are a good £100 for 8 bolts :o expensive little fuckers

not really going for more than 160bhp, if i were to drop the TB's and just use a single one how hampered would the engine be on power and maybe go TBs at a later date

I have to admit if strongly recommend rods!
Check out the first page of my rallye build thread to see what can happen without lol

iv seen that before looks nasty!

Think John said elsewhere - rods are dependant on rpm not power. Standard rods with ARP bolts are strong as an Ox, but I'd not want to give them silly revs.

what sort of limit would you run with stock rods, realistically i dont want all the power at 8.5k and none bellow, id rather have less power over all but more power for the given revs lower down in the range (if that makes sense)

[Ross]

John's the man to ask tbh, my knowledge is in boost, not high power NA. I'd *guess* that the rods are fine for a 7.5k limit, but you'd be pushing your luck much above that, but please don't take my word for it double check with John etc. :)

[barwell1992]

John's the man to ask tbh, my knowledge is in boost, not high power NA. I'd *guess* that the rods are fine for a 7.5k limit, but you'd be pushing your luck much above that, but please don't take my word for it double check with John etc. :)

cool cheers so about 300rpm over standard


next question, mpg N/a vs boost bhp for bhp what would be more economical under normal conditions eg not trying to save fuel

[jeffchiz]

if your not going for more than 160bhp then no point at all in fitting high comp pistons only need for them or i should say the main reason why people fit them is to use higher lifting cams, definitely wouldnt buy high comp pistons then only having mild cams especially if your not sure on to go t/b's

id just stick to a set of cams, predator ecu and some breathing mods and see how you feel after that, tom5190's 16v using 743's and oem ecu is pretty much the same as my engine using 708's, jenveys and pred, i wouldnt say the cost of the pred and the jenveys were worth it if your going high comps and throttle bodies then jsut chuck in some better cams and get 190bhp no point in just sticking to 160bhp if your gonna go for the pistons anyway

[barwell1992]

hmm dont the more aggressive cams work high up the rev range that would be limited by the rods kinda defeating the point if i dont get rods a well? (out of budget after ever thing else)

[welshpug]

yup, you got it.

[jeffchiz]

look at tom5190's posts, you can get cams that still use hydraulic lifters and achieve 190bhp i know of at least a couple cars

and if you are intent on not using better cams then why even bother thinking about high comp pistons or forged rods??

seriously a cammed remapped 16v will give you 99% of the power your aiming for

bodies are only worth it if going for over 160bhp so you can utillise wilder cams really isnt worth it, im talking from experience

[greyjasper51]

Speed = money
Money = power

How much you got pretty boy?

[jeffchiz]

here is a graph with mine and tom's overlayed

i achieved 4bhp than him overall, my curve is a little higher and torque is slightly better but on the road theres shit all in it
http://i1163.photobucket.com/albums/q547/jeffchiz2/SamTomBHP.jpg

[barwell1992]

though so

so this is the 3 specs i have so far that i like the look off

180bhp+? expensive option
Wossner pistons and rods £900
ACL shells £57
ATP tb's £900
management £800????
valve stem seals £20
Head gasket £38
Cat cam 743 £300
Newman uprated valve springs £91
time....£ priceless lol

total £3.2k ish

150bhp+ Option 2
ACL shells £57
ATP tb's £900
management £800????
valve stem seals £20
Head gasket £38
Cat cam 708 £300
ARP rod bolts £100

Total £2250ish

140bhp ish option 3
ACL shells £57
management £800????
valve stem seals £20
Head gasket £38
Cat cam 708 £300
ARP rod bolts £100

Total £1250

what do you think ? could i run 743 cams with option 2+3 or would i need forged pistons for that cam

leaning toward option 3 just because theres so much less cost ect the rest of the money can go on other things like gear box rebuild ect

[Sandy309]

If it's a hydraulic lifter build, then little point in improved rods, because you'll be inside the "safe" threshold of standard rods anyway.
What are improved rods? I can example numerous failures I've seen with poor quality aftermarket rods (PEC, DP, Cat cams included, happy to provide pictures and details for anyone that questions it), down to basic design flaws, questionable materials and manufacture. You'll struggle to find much else for sale though, because all the dealers/suppliers favour the products with a low price and good margin and just blame whoever assembled it if it goes wrong. I've NEVER had a failure with the preferred rods I use (Arrow, Robson, Carrillo), even with total loss of oil supply and deep into 5 figures rpm; but every engine I built in the past with lower quality rods has given me a problem, eventually (fatigue).

Note also that the package prices on Ebay for "Wossner pistons and forged rods", are not Wossner rods in any I've seen, but the PEC ones. Not that I'm holding up Wossner as a brand of quality, but the offer is worse than you think!


The broader issue, with rpm and power, is that you do not need to rev the crap out of an N/A engine to make good power. My best TU race engines are making over 200bhp at 7000rpm. Power is simply torque multiplied by engine speed. If you make enough torque, you'll get the power at lower rpm through better efficiency. It's that simple. Getting high torque from an N/A engine is not easy though, so in most cases engine builders just work towards revving the engine more, to make the torque they can at higher rpm and see a higher power figure that way (exaggerated by rolling road testing, which tends to make power appear at higher rpm due to transmission loss characteristics compared to a true engine dyno). If you focus on "flow" development, that tends to be the kind of engine you get. Improving torque at moderate engine speeds takes a much more detailed approach to the overall inlet and exhaust pipe designs, chamber design and the cam/compression relationship with the rest. The overall engine performance tends to be much better with an engine developed in that way.
More than anything, I would encourage whoever to think about efficiency more than increasing rpm and to try to choose components that will work well together within your budget and a sensible rpm limit, rather than spanking large amounts on aftermarket rods, the money might be smarter spent elsewhere!

[jeffchiz]

743s are just the updated version of the 708s I don't think you can even buy 708s any more

[gazza808]

Always amazes me that the PEC rods that are near on 500quid I can get for 240quid delivered even with mateys percentage on top, just shows how much they are ripping you off.
They aren't quality at all.

[luthor1]

"Over 200bhp at 7000rpm"

Is that on a 1587cc TU?

That's 94.55lbsft torque per litre at 7,000rpm. How much "over" 200bhp are the engines making at 7,000rpm? Because 201bhp is 95lb, 202bhp is 95.5lbsft and so on

Just curious...

[Ross]

I've seen some serious builds on PEC kit (that make my engine look like a tonka toy) without issue - what's been your problems Sandy? I know a lot of the VAG boys recommend PEC, including several with 1000+bhp setups.

[gazza808]

Pec rods are cheap crap, they'll tell you different but it's fact, I can get them and less than half pec's prices from some one who sells them in Europe, I've seen 5-600bhp c20let builds on them,
But as the man who sells him self says 'its luck of the draw if you get 10miles or 10k miles out of them'
Quality is hit and miss.
But tbh I'd give them ago just cause I can get them so cheap, couple hundred quid more than the pec rods and you can get arrow rods.

[AndySAXO]

Hmm interesting... Maybe change my plans reading this

[barwell1992]

The rods I were looking at are GMC own branded ones any oppinions ?

[Sandy309]

"Over 200bhp at 7000rpm"

Is that on a 1587cc TU?

That's 94.55lbsft torque per litre at 7,000rpm. How much "over" 200bhp are the engines making at 7,000rpm? Because 201bhp is 95lb, 202bhp is 95.5lbsft and so on

Just curious...
It's going to be over 1587cc if forged pistons are being used, most people go for the 79-80mm size, giving up to 1649cc and most people on here are not trying to keep the engine under a class cc limit.
I'm not going to give away the bore size specifics of my top spec engines, but example 206.6bhp at 7000rpm (155lbft) on a standard crank, standard stroke. Highest torque I've seen from a standard crank TU so far is 159lbft@6500rpm, 95lbft/litre is typical from my 1600 TUs, but over 1600cc the specific torque reduces. My best XUs are over 97lbft/litre, all on standard V-power, calibrated and DIN corrected engine dyno; stable steady state readings.

[luthor1]

159lbsft - Wow, that's literally unbelievable assuming 1649cc
Current F1 engines can only struggle out 94lbsft/litre give or take and I thought they were pretty good

And that's more than the pug1off XU engine, and the Merlin Developments ITCC 306 racecar!

Good work!

[Sandy309]

The potential for torque/litre diminishes with rpm, so comparisons with F1 engines don't really work. BTCC Supertouring and works rally engines (before the single throttle regs) are the closest comparisons. The Nissan SR20 and Honda F20B touring car engines were well over 100lbft/litre at the peak of their development.

I dyno about 50-60 engines a year for some of the best 4 cylinder N/A engine builders in the country and yet to see better torque/litre from a circa 2 litre than my best 2040cc XU. That includes top spec JRE C20XEs and SBD Duratecs that win just about everything.

[welshpug]

From what I can find on Google the current F1 engines aren't even that high, but its a poor example to use as they are not designed specifically for torque in any way at all, though many do work on that aspect, Renault and Ferrari it seems, they have blinding starts.


Blah, too slow with the googlefuu :P

[luthor1]

Yes perhaps F1 was a poor example, could you point me towards websites showing those high power 100lbsft/litre engines as I'd love to have a good ready!!

[KamRacing]

Theres some good advice here.

160bhp is certainly an achievable figure. Your first issue on spec is to keep the cam profile mild enough that you get a good idle and will pass emissions. Something like the 1321743 (http://www.kamracing.co.uk/citroen-saxo-vts-fast-road-camshaft-set-cat-cams-1321743.html) will do the trick. This will need no other modifications to the head. (708's are discontinued). Things like uprated springs will increase parasitic losses of the engine and should only be upgraded if necessary. Throttlebodies will certainly help but you want to get the right induction length. This has a big effect on power delivery and peak numbers. Do your research and choose wisely.
Its not a case of just bolting a load of bits on.

[Tom5190]

though so

so this is the 3 specs i have so far that i like the look off

180bhp+? expensive option
Wossner pistons and rods £900
ACL shells £57
ATP tb's £900
management £800????
valve stem seals £20
Head gasket £38
Cat cam 743 £300
Newman uprated valve springs £91
time....£ priceless lol

total £3.2k ish

150bhp+ Option 2
ACL shells £57
ATP tb's £900
management £800????
valve stem seals £20
Head gasket £38
Cat cam 708 £300
ARP rod bolts £100

Total £2250ish

140bhp ish option 3
ACL shells £57
management £800????
valve stem seals £20
Head gasket £38
Cat cam 708 £300
ARP rod bolts £100

Total £1250

what do you think ? could i run 743 cams with option 2+3 or would i need forged pistons for that cam

leaning toward option 3 just because theres so much less cost ect the rest of the money can go on other things like gear box rebuild ect

Your really over thinking it for the 140 & 150 hp setups.

Here is some (these are only from experience obviously there are other ways of reaching this with other parts etc)

Package 150hp (7600rpm limit):
CatCam 743's
P&P Throttle body
ECU Remap (standard ECU)
Raceland 4-2-1 manifold
Supersprint centre pipe and rear box

Package 165hp (8000rpm limit):
AT Power Throttle boddies
Newman PH3 cam's
Emerald K6 ECU
Piper 4-1 Manifold
(not sure on exhaust after that but probly irrelevent at this stage)

If your happy with 160hp +/- then the above package is more than enough providing you have a good engine you dont need to do anything to the bottom end.

[Ross]

don't need the K6 (or another standalone) if you've got a set power requirement and are confident you wont change that. Just a standard ecu remap.

Of course, if you're like everyone else on the planet, you'll change your mind, then the standalone ECU is very much worth it :)

[Tom5190]

You mean keep the standard ECU?

[welshpug]

To give you an idea of a similar setup.

170 bhp/140 lbft.

cat 850's (solids)
pec rods+pistons.
standard head and crank.

satchell GSXR inlet, DTA.

Piper manifold+exhaust.

http://sphotos-f.ak.fbcdn.net/hphotos-ak-prn1/530502_10150770911170985_1901564531_n.jpg

[Ross]

You mean keep the standard ECU?

Yes - a remap on the standard ECU can be just as good as a map on a standalone ECU. If you don't need the other features offered by the standalone, then the standard ECU is capable.

[Tom5190]

Yes - a remap on the standard ECU can be just as good as a map on a standalone ECU. If you don't need the other features offered by the standalone, then the standard ECU is capable.

Yea it is possible however that exact one was done with a standard ECU at said place and spent 3-4 months not running properlly sadly.

[Ross]

Yea it is possible however that exact one was done with a standard ECU at said place and spent 3-4 months not running properlly sadly.

where was it done?

[axsaxoman]

All the work would be done my self as far as the engine is concerned , I have a lot of equipment at my disposal as my work used to be a Machine shop for jordans f1

Didn't think there was a pred 3 plug ? , but cool thank for the help I dont even have the engine yet so won't start planning until I get it apart ect

So what does this spec sound like then

High comp pistons and rings
Fast road cam or more extream with pulleys
Solid lifters and uprated springs
Multi throttlebodies
Ped ecu
Smooth inlet and exhaust ports
Service head lap valves ect

And get someone eles to do the wiring lol :-p

What about fuel supply, fpr uprated pump ?

my first post i thought made it very clear to decide on bhp or budget then make a shopping list
your next post saying 150-160 bhp

so why do we have forged rods ,high comp pistons etc in the list --waste of money as is fitting arp bolts --for that spec i note another poster is saying 190bhp on std lifters --totally mad and wrong --no car maker anywhere in the world uses hydraulic lifters above 7500rpm and you cannot get 190 bhp from a tu5 engine below that rpm without boost . and at 190bhp no way wil it pass ant MOT test or be an evryday driver for town use

the wossner pistons + rods at £900 are not using wossner rods .
I am not saying that the rods are crap --but not wossner
yes there are alot of crap ones
wossner rods are around £900 inc vat on there own .
same goes for using cams of a higher duration then our gmc cams or the 708 or ph3 --you will not get a REAL mot pass and to get good sensible idle you will need close down the EX cam --which will pull the rpm down where max bhp is made and also you may loose a small amount of bhp as well.

[luthor1]

John,

Sandy can get 200bhp at 7,000rpm, see post #28!

Not sure of his spec though, but he can do that, so it is possible - what did you think the limit is for 7,000rpm out of curiosity??

Kind regards
Andy

[blackie_2k5]

Those are race engines and not on hydros though andy


Thik the point he's making is on Oe engines with hydros still fitted??

Edit- reading it back I see what your getting at andy

[luthor1]

I know that, but it's still 200bhp @ 7,000rpm, it's flowing that much air. It's making similar bhp to a turbo'd 'stock' engine running 0.7bar of boost!

It's incredible!

[blackie_2k5]

See edit ^^

Lost net connection haha

[jeffchiz]

I think John is talking about my comments I am just commenting on engine build that I have seen and dynod on the same road mine was mapped on

[barwell1992]

ok then, i will go for 150bhp as my target for the moment

the reason i spec ARP rod bolts and ACL shells is because i have to stip the bottom end anyway to find a knock and if i ever want to go with more power then they are there and i wont have to open the bottom end again ? or is that pointless?

so would i be looking to go with

ph3 or similar ? basically just cam the standard engine ? and a map on a pred or other ?

[Ross]

no car maker anywhere in the world uses hydraulic lifters above 7500rpm and you cannot get 190 bhp from a tu5 engine below that rpm without boost
Sandys engines make 200+ bhp at under 7500rpm John, and frequently below 7000rpm. But as sandy will tell anyone - it's about the drivability under the curve more than a headline figure too :)

Just pointing out its possible. :)

http://www.goodhand.co.uk/sandy/files/SBTU6v2012.jpg
http://www.goodhand.co.uk/sandy/files/SBmarch05.jpg

[blackie_2k5]

ok then, i will go for 150bhp as my target for the moment

the reason i spec ARP rod bolts and ACL shells is because i have to stip the bottom end anyway to find a knock and if i ever want to go with more power then they are there and i wont have to open the bottom end again ? or is that pointless?

so would i be looking to go with

ph3 or similar ? basically just cam the standard engine ? and a map on a pred or other ?

if that is the power you want..cams and a map should do that mate

from which case id rahter find a healthy engine and save yourself the wasted time and money rebuilding a lump with bottom end failure (which may incurr alot more costs then you expect if its damaged anything internally)

[luthor1]

he's not using the lambda gauge in that picture is he :D

LOL! Nice graph

[barwell1992]

if that is the power you want..cams and a map should do that mate

from which case id rahter find a healthy engine and save yourself the wasted time and money rebuilding a lump with bottom end failure (which may incurr alot more costs then you expect if its damaged anything internally)

Maybe but for £50 it'd worth a punt, cranks are £25 on eBay and rods and pistons the same so I'm not to worried at least I will know it will last a bit longer than and lump that's iv not seen the inside off

[blackie_2k5]

£50 engine
acl mains and big end bearings +/- £140

possible crank/rods/pistons fucked.....xx amount

getting the second hand stuff checked to see if its still in tolerance xxxx amount


buy a decent 16v engine... £150-300..fit and forget

is it worth the hassle mate? id rather buy an engine from a reputable forum user and spend that money on a new cambelt kit and water pump..and other parts to get your engine on the go

you say you dont know the innard of x engine...bottom end failure does just happen some times...but alot of times its from lack of oil

[barwell1992]

£50 engine
acl mains and big end bearings +/- £140

possible crank/rods/pistons fucked.....xx amount

getting the second hand stuff checked to see if its still in tolerance xxxx amount


buy a decent 16v engine... £150-300..fit and forget

is it worth the hassle mate? id rather buy an engine from a reputable forum user and spend that money on a new cambelt kit and water pump..and other parts to get your engine on the go

you say you dont know the innard of x engine...bottom end failure does just happen some times...but alot of times its from lack of oil

Good point well taken, might pick it up still for a bit of a look, as I said have a lot of equipment at work like bore gauges ect so If it turns out ok then bonus if not then ill just sell off the good bits

[axsaxoman]

John,

Sandy can get 200bhp at 7,000rpm, see post #28!

Not sure of his spec though, but he can do that, so it is possible - what did you think the limit is for 7,000rpm out of curiosity??

Kind regards
Andy

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