250bhp, how much do we need?

2nd February 2011, 22:40

im shopping

what do we need for 250bhp atf? forged low comp pistons, t25 at around 1 bar? can i use the predator ecu and 306 gti injectors? ive never seriously considered tuning saxos to that sort of power, so not sure what id need to go above 170/180bhp

2nd February 2011, 22:51

to get 250bhp at flywheel youd need

descent maniflold
t25 or bigger
standalone ecu
bigger injectors (upwards of 330cc)
intercooler
good exhaust system
if up to 250 decomp plate or double headgasket
over 250 forged pistons
over 300 would need a few more parts including forged conrods etc

bare in mind a "budget" conversion wont just bolt on and you will need to do most of the work yourself inluding boost pipes, oil feed/return, modified sump, diff rad etc etc

2nd February 2011, 22:58

just lookin at dp engineerings website at manifolds, downpipes and forged pistons. student loans gonna get rinsed...
is a k03s any good, my mates stripping his mk4 golf gti so i might be able to get the turbo away for nothin if it will be any good.
im more than up to carrying out the work myself

2nd February 2011, 23:17

Quote:

Originally Posted by LeeM

just lookin at dp engineerings website at manifolds, downpipes and forged pistons. student loans gonna get rinsed...
is a k03s any good, my mates stripping his mk4 golf gti so i might be able to get the turbo away for nothin if it will be any good.
im more than up to carrying out the work myself

dp engineerin stuff is about the best out there for these cars.. they are expensive though.

k03s is good for around 230-240hp, id rather use k04 or td05 16g as i personally think they would be a good match.
theres only so much you can do yourself too unless you can weld (tig and mig) etc

2nd February 2011, 23:23

talking of decompression plates, do i need 2 x standard saxo head gaskets and the thickest decomp plate i can find for my turbo conversion? as the head has been skimmed twice i believe so compression will be above normal if im ryt in thinking. going for 8 psi which i think is safe with the decomp plate installed.
also does losing compression make the engine not as responsive? sure i read that sumwhere...

2nd February 2011, 23:27

Quote:

Originally Posted by stevo1600

talking of decompression plates, do i need 2 x standard saxo head gaskets and the thickest decomp plate i can find for my turbo conversion? as the head has been skimmed twice i believe so compression will be above normal if im ryt in thinking. going for 8 psi which i think is safe with the decomp plate installed.
also does losing compression make the engine not as responsive? sure i read that sumwhere...

with a decompression plate you use a headgasket on the block, then the decomp plate, then sealant, then the head. you have to use proper sealant too.

really you need to try and work out what comp ratio you want, then find out what gaskets you would need to achieve the desired CR then just go for the next thickest combo.
if you go too low on CR the responsivness of the engine off boost will suffer as will turbo lag.

2nd February 2011, 23:28

i can weld

what do i need to weld though, just my oil return to the sump?
looking at the cituning manifold and downpipe but what turbo is there downpipe suitable for?

2nd February 2011, 23:30

what is the standard c/r on a vts? dp sell some that lower it to 9:1 isnt it 10.5:1 as standard?

2nd February 2011, 23:32

Quote:

Originally Posted by LeeM

i can weld

what do i need to weld though, just my oil return to the sump?
looking at the cituning manifold and downpipe but what turbo is there downpipe suitable for?

depends on what your doing yourself, for example im doing my own 1 piece boost pipes so need to weld those up. and im making my own manifold and exhaust system, and made my own intercooler so that too... its a long list if you do a lot yourself.

i think they house the gt17 and im sure ive heard t25's being used with them but im not certain.

2nd February 2011, 23:34

thanks mate for the reply,

so basically if i go to thick im gunna suffer lag and responsiveness issuses and if i go to thin ill risk detonation...

i myt just put a 1.9mm headgasket on it from gmc i think its the thickest one they do so surely that will be OK at 8psi.

how would i work out my current CR using a CR gauge measuring each cylinder or?

2nd February 2011, 23:35

i like the look of this... http://www.dp-engineering.nl/EN/prod..._16v_compo.php
chuck in some forged low comps, an intercooler, some new injectors and a predator ecu and it comes in about £3k.
im gettin £6k in loans and can probably document some of the work and use it towards my degree, i can definately justify that...

2nd February 2011, 23:37

Quote:

Originally Posted by LeeM

i like the look of this... http://www.dp-engineering.nl/EN/prod..._16v_compo.php
chuck in some forged low comps, an intercooler, some new injectors and a predator ecu and it comes in about £3k.
im gettin £6k in loans and can probably document some of the work and use it towards my degree, i can definately justify that...

that is a good kit, aslong as you match on quality of the extra parts it will be a strong build

2nd February 2011, 23:39

is that gonna see me to 250bhp? 250 is just the number i want lol

2nd February 2011, 23:42

Quote:

Originally Posted by stevo1600

thanks mate for the reply,

so basically if i go to thick im gunna suffer lag and responsiveness issuses and if i go to thin ill risk detonation...

i myt just put a 1.9mm headgasket on it from gmc i think its the thickest one they do so surely that will be OK at 8psi.

how would i work out my current CR using a CR gauge measuring each cylinder or?

i think that will be ok for just 8psi, or try 2x 1.2mm gaskets.
im using decomp plate and will be wanting to run 15psi but il have standalone ecu, bigger injectors etc so less chance of going bang (with good mapping)

that would be the only way to measure true CR but its far too much hassle for my liking. standard CR is 10.8-1 there are formulas on the internet to work it out.

2nd February 2011, 23:44

if you have a vts which i think you have? with that kit aswel as what you mentioned and a decent map i reckon you could push 250bhp probably, either way 200bhp+ in a front wheel drive car is gunna be mental, torque steering ripping up tires gearboxes clutches etc. have you thought of better suspension to cope with the power aswell as a big brake kit? it will go like stink but you want it to stop just as quick aswel as handling good. so add those onto your budget unless you dont want them...

2nd February 2011, 23:44

god, i was planning on a cheap track slag. my mental shopping list is pushing £4k now! i expect all the suspension and body to be done by may/june then start on the turbo in september so plenty of time to get enough money together

2nd February 2011, 23:46

Quote:

Originally Posted by LeeM

is that gonna see me to 250bhp? 250 is just the number i want lol

depends what turbo and what boost and lots of other things but 250hp would easily be achievable with that kit.

also, dont just add up the big stuff like that as you will never hit budget. whatever number you came up with,,, almost double it and thats what it will realistically cost.

2nd February 2011, 23:48

thanks danny

i think i myt buy 2x 1.2mm headgaskets then as the head on my car has been skimmed twice im 98% sure of it. i had it skimmed a few months back and when i took it off i could see where the milling disc had took sum off the head. so better to be a lil low on compression than my engine going pop.

2nd February 2011, 23:49

haha i know! i want 306 gti brakes, bilsteins, poly bushes, solid wishbone mounts and strut braces. thats the best part of a grand lol!
sweet talk my dad for my birthday for most of that little lot though

and i still need to find a 16v engine!

2nd February 2011, 23:51

if you can carry out the work your self you will save a HUGE amount of money. a cheap track slag doesnt have to be 250bhp

170-180 is nice power ;p and will cost half as much to do. combined with good tires, brakes, suspension etc will be quick round a track.

2nd February 2011, 23:54

wel if you found a 16v engine, just hire an engine crane or the other thing you can get forgot what its called but it holds the engine when you work on it.. and start working on it as money comes in

then wack it in and away you go lol ;d

2nd February 2011, 23:56

dont forget that with 250hp will be over 200lb ft torque, wich will pull apart a standard diff apart pretty quickly, so a lsd is advised. also uprated engine mounts AND a proper clutch to cope with that extra torques...

there is a reason that EVERYONE aint doin it, its expensive and hard work.

3rd February 2011, 00:03

its going to be an ongoing project, not my road car so doesnt matter how long it takes. the longer the better tbh because it will keep me entertained.
forgot about a diff

another £500+ haha. again i can fit a diff myself, probably cheaper to just buy a few boxes and change it every time it blows ha ha

3rd February 2011, 00:24

T25 at 8psi won't get you 250 bhp. What do you want? 8 psi and decomp, or forged and 250bhp? Give said both.

Hidden costs are the killer. Above mentions £3k. 250bhp and you'll kill a MA box if you drive it hard - BE gearbox, mounts, driveshafts etc. Allow a grand for that. Fuel pump, map sensor? Boost pipes? Oil feed? Water pipes for turbo? Radiator? Fan for radiator? Header tank?

It all adds up and fast. No one thinks of needing a new fan when you get a dp manifold - that adds £80 on it's own. Diesel rad? £50. Header rank? £80. Hose clamps for boost pipes? £50. See what I mean? Clutch? £350.

Speaking of the magical 250bhp your after, on who's rollers do you want that? I can take you to a place where 200bhp and you'll get a graph of 250 as it's full of shit. I can also show you a place where others claim 250 and the REAL figure is 220 or whatever. Everyone says their dyno is accurate. Few are. Best to just stick with one place and watch the improvement over the life of the build - don't set your heart on a particular figure

Good luck

3rd February 2011, 00:30

ross, shauns old setup on gt25r was 26*hp at 1 bar

3rd February 2011, 00:33

just to add, it is fair to say a gt25r is a bit different to a t25

im going to try some funky turbo for the next stage of my car.

3rd February 2011, 00:53

Quote:

Originally Posted by dannygti

ross, shauns old setup on gt25r was 26*hp at 1 bar

Yeah. And mine with a better setup, bigger turbo and 10 psi more only made 280. Weird that eh?

3rd February 2011, 08:13

is there an ideal cam for a turbo setup, or do the standard cams do the job fine?

3rd February 2011, 08:25

Quote:

Originally Posted by dannygti

also, dont just add up the big stuff like that as you will never hit budget. whatever number you came up with,,, almost double it and thats what it will realistically cost.

BEst advice ever.

I got told the same when i started mine ignored it and my budget has literally doubled when i built it.

Stevo1600: You dont need a decomp plate to run 8psi, it will be fine at standard compression IF its mapped right.

3rd February 2011, 08:53

Little things like £100 worth of oil pipes and stuff all add up! I don't expect it to be cheap, and I don't expect to finish within the next 18 months either lol! Not starting on the turbo stuff till after summer, I need to car in a roadworthy useable state to go to the ring in July

then when I'm back I'm gonna start the engine mods

3rd February 2011, 09:13

Quote:

Originally Posted by LeeM

is there an ideal cam for a turbo setup, or do the standard cams do the job fine?

standard cams are actually very good for 250bhp

3rd February 2011, 10:47

Quote:

Originally Posted by LeeM

its going to be an ongoing project, not my road car so doesnt matter how long it takes. the longer the better tbh because it will keep me entertained.
forgot about a diff

another £500+ haha. again i can fit a diff myself, probably cheaper to just buy a few boxes and change it every time it blows ha ha

not a good idea and wrong thinking ,breaking things will ruin your day out --and the days of finding any number of good s/h g/boxs is long gone ,better to build it right once + forget it .
providing its going to be used as a track day car --which does not invlove repeated drag starts --then no need for a BE at that power . and fitment of an lsd is a must to get a good lap time ,even more so with a turbo due to the way the power comes on ,wheelspin is not conducive to a good lap time or tyre life
If how ever you want to wheelspin it to death in the asda car park --then expect lots of transmission problems .

3rd February 2011, 10:50

Quote:

Originally Posted by axsaxoman

not a good idea and wrong thinking ,breaking things will ruin your day out --and the days of finding any number of good s/h g/boxs is long gone ,better to build it right once + forget it .
providing its going to be used as a track day car --which does not invlove repeated drag starts --then no need for a BE at that power . and fitment of an lsd is a must to get a good lap time ,even more so with a turbo due to the way the power comes on ,wheelspin is not conducive to a good lap time or tyre life
If how ever you want to wheelspin it to death in the asda car park --then expect lots of transmission problems .

My favourite past time

3rd February 2011, 10:53

Quote:

Originally Posted by LeeM

just lookin at dp engineerings website at manifolds, downpipes and forged pistons. student loans gonna get rinsed...
is a k03s any good, my mates stripping his mk4 golf gti so i might be able to get the turbo away for nothin if it will be any good.
im more than up to carrying out the work myself

once you looked ta their site and added all the extra bits like oil feed and return andturbo cooling bits etc --then comapre to s/c
it will be cheaper + simpler to fit and a lot easier to dirve quickly on a track .
obviously if you are now talking about home made using s/h turbo,s or mexican copies etc --then no a new s/c would not be cheaper ,but still alot simpler to fit and not the same heat issues ,less uncontrolable wheelspin and kinder to the transmission

3rd February 2011, 11:10

I want a turbo though

I love it when a car comes on boost. I will look into supercharging though. Do you need standalone or can a supercharger run on the standard ecu with it not coming on and off boost?

3rd February 2011, 11:19

l16_vts is selling all new dp stuff, injectors, i/c etc in the sale section. Grab a bargain!

3rd February 2011, 11:26

Definitely can't afford to start buying stuff yet! Though I'm getting tempted to stick the Corsa up for sale and then use that to buy everything, but then the whole ongoing project idea goes out the window and I'd have to do everything in a week lol

3rd February 2011, 11:37

I agree with you on wanting a turbo rather than a supercharger. Nothing better than feeling a car take off when the turbo spools, and they sound better

3rd February 2011, 11:50

Quote:

Originally Posted by LeeM

I want a turbo though

I love it when a car comes on boost. I will look into supercharging though. Do you need standalone or can a supercharger run on the standard ecu with it not coming on and off boost?

I know you are wanting to save money ,and your choice is maybe a turbo ,bu t DO NOT even consider attempting to get anything close to that power with a std ecu .
yes in theory becuase the boost will be the same at any rpm ,that you could remap the std ecu to suit , and yes you could do it probably with an aem FIC controller + larger injectors ,but to even consider attempting this with no ecu mods is not possible .
I fyou modifed your target down to say 180 bhp then you coud use std pistons + extra ijector dirver ,etc ,but by the time you have done all that the end cost is so close to an ecu system,not worth it

3rd February 2011, 12:54

250bhp can be achieved without a decomp plate and without forged pistons.

I've ran mine on standard internals for over a year with just a 1.9mm head gasket.

don't bother buying forged internals, waste of money. if my engine ever goes bang i'll buy another one for £200! I could do that 6 times before it would of made sense to forge it.

anything above 300bhp in a fwd on 15's is a waste of time anyway, welcome to wheelspin city. 250bhp is a good figure, it will be able to get the power down, you can get that power on a small turbo (no need for a gt28 = lag and await the wheelspinning) so it will spool quick reducing wheelsping again as the power delivery won't be so aggresive.

3rd February 2011, 13:01

i have a full parts list available for 250bhp spec build
also 300bhp build list.

info@atspeedracing.co.uk

all with add-on upgrades available. specs are made for future upgrades in mind.

- colin.

3rd February 2011, 13:07

Quote:

Originally Posted by maddison_vts

anything above 300bhp in a fwd on 15's is a waste of time anyway, welcome to wheelspin city. 250bhp is a good figure, it will be able to get the power down, you can get that power on a small turbo (no need for a gt28 = lag and await the wheelspinning) so it will spool quick reducing wheelsping again as the power delivery won't be so aggresive.

You sure do talk some utter tripe...

3rd February 2011, 13:14

Quote:

Originally Posted by RossDagley

You sure do talk some utter tripe...

don't see how, i get traction issues with sub 300bhp so anything over 300bhp will definitely have traction issues.

3rd February 2011, 13:36

I don't think I'd be happy goin for 200+ on just a thicker headgasket. Although I suppose I could try it and then put forged stuff in after the standard pistons melt

3rd February 2011, 13:50

Quote:

Originally Posted by maddison_vts

don't see how, i get traction issues with sub 300bhp so anything over 300bhp will definitely have traction issues.

Dont press the loud pedal so hard? Get a decent set of tires and a decent diff and you're sorted. No idea what tires you've got, but you've got a quaife, so thats a good start - but the MA box is lively anyway - taming that is always a struggle.

I obviously get traction issues - but once you're at speed, that extra power comes into it's own. Get dirty on it's ass, and of course you can break traction - but drive it with sympathy and not only will components last longer, but your times will improve.

3rd February 2011, 13:53

Quote:

Originally Posted by LeeM

I don't think I'd be happy goin for 200+ on just a thicker headgasket. Although I suppose I could try it and then put forged stuff in after the standard pistons melt

Set up and mapped right it can be done safely. Ive no idea what power mine is running but its doing 1.2bar on standard internals and standard head gasket

3rd February 2011, 13:55

Quote:

Originally Posted by Jungle

Set up and mapped right it can be done safely. Ive no idea what power mine is running but its doing 1.2bar on standard internals and standard head gasket

did you not get a power figure when it was mapped or "set up right"?

3rd February 2011, 14:07

Quote:

Originally Posted by RossDagley

did you not get a power figure when it was mapped or "set up right"?

No it was live mapped not on rollers. I would make a guestimate at circa 200bhp, but as everyone knows power figures are for bragging only.

Please tell me your not trying to suggest it hasnt been mapped or set up correctly?

3rd February 2011, 14:26

Quote:

Originally Posted by Jungle

Please tell me your not trying to suggest it hasnt been mapped or set up correctly?

I'm not suggesting anything.

I don't know how you can safely (or accurately) map a car on the road though - holding a load site at 100+mph for example. Not my cup of tea!

3rd February 2011, 14:34

Quote:

Originally Posted by RossDagley

I'm not suggesting anything.

I don't know how you can safely (or accurately) map a car on the road though - holding a load site at 100+mph for example. Not my cup of tea!

Its mapped accurately. Was done on private roads. If it wasnt it wouldnt be running as well as it is. The 2009 winner of FWD at TOTB was mapped using the same methods (not the same company), its all down to the skill of the mapper and the driver

3rd February 2011, 14:46

Quote:

Originally Posted by RossDagley

I'm not suggesting anything.

I don't know how you can safely (or accurately) map a car on the road though - holding a load site at 100+mph for example. Not my cup of tea!

use a lower gear?

3rd February 2011, 14:53

Quote:

Originally Posted by KamRacing

use a lower gear?

wheelspin.

3rd February 2011, 14:59

I can hold all necessary load sites in 3rd gear without wheelspin. Only spins when bieng nailed but its not hard to hold your foot to the floor.

3rd February 2011, 15:28

Quote:

Originally Posted by Jungle

I can hold all necessary load sites in 3rd gear without wheelspin. Only spins when bieng nailed but its not hard to hold your foot to the floor.

Holding full power in 3rd just isn't an option on a high-boost car though. That was the angle I was coming from.

3rd February 2011, 15:35

Yeah fair point for that we used 4th and 5th. Not traveling at any great speeds for more than a few seconds though, and its not holding a load site as such its just holding throttle wide open so you can concentrate on the actual driving.

3rd February 2011, 23:35

do cituning not do a downpipe with the 5 bolt fixing to suit a gt25?