forevaford

iTrader: (2)

hi
my saphire cosworth is pretty fast but has verry little turbo response, 1.5 bar boost is reached at 4000 rpm ish, and when i change gear it takes a few seconds to boost again. i was wandering if i could use a 4x4 turbo manifold for better spool up??

my spec is ported head, 2wd ex manifold, welded elbo on 4x4 inlet manifold, 10mm spacer plate, 500 intercooler with 70mm pipes, t34.48 turbo, bd 14 inlet cam.
iv thaught about using a gt 28 (or gt30) turbo, the car is verry difficult to drift atm with the lack of turbo response. the 0.48 housing feels more like a 0.63!
i think my problem is my pipes and intercooler and spacer plate is too big.
whats the biggest turbo i cud ideally use on a 4x4 manifold? (with suitable flow characteristics) minimum bhp required is 370
thanks for any help
martin

martysmartie

iTrader: (1)

The turbo you have is perfectly capable of providing 370 + all day long as is the standard engine. I would first do the obvious check to see if you have a boost leak this is assuming it has run well before if not it may be to do with the setup of your car as it seems a little complicated for the result you are trying to achieve.

Martin

tabetha

Why a BD14 if wanting 370, the std engine and T34.48 will do this all day long, it will be a bit laggier with a BD14 in place of the std inlet cam, maybe put the std one back.
My T34.48 starts boosting at 1400rpm, and full boost by 2500rpm, has mild head porting std cams running around 17/18 psi, but mine was mapped on aftermarket ecu, also does 40mpg on a run no problem too.
The difference in off boost power was amazing when I went to a aftermarket ecu emerald K3, best thing I ever did by a mile, just kicked myself that I ever wasted decent money on chips etc before hand.
tabetha
tabetha

forevaford

iTrader: (2)

ummm ok, the car origionally had a t38.63 on an was 420 bhp at just over 2 bar. that turbo blew, so back on with the t34 and greens. but the lag is the same if not worse! i think your right, its got too many things for this turbo (turbo too small) and chip setup possibly wrong.
tabethas setup sound great! is yours a 2wd turbo manifold still?
iv been to wales in mine today did 250 miles to a full tank of fuel, thats with the odd 150mph overtaking sprints, so its not too bad, i think its 20mpg ish.
i think i need to bigger my turbo and have big power again or smaller my cam and air vollume between turbo and head (smaller pipes, remove spacer plate etc)

tabetha

Do I understand correct you are still using the T38 chip ?, this will be a whole world of pain for the engine fuelling wise with such a big change, needs mapping or at the very least a chip to suit to get anywhere near correct, mapping would of course be 100% correct if done correctly, depends how deep you pockets are.
Yes I'm on std 2wd exhaust manifold and inlet, just raised CR to 9.1:1 though for new build, only took pistons today for sizing to the block final cut, glad to see if still had it's deck plate on about 4" thick iron, otherwise the top 35-40 of the 205 blocks don't come out true, cylindrically speaking.
tabetha

forevaford

iTrader: (2)

iv got a different chip for my big turbo setup with 88lb injectors, when my turbo spat its dumby i put greens back in and a chip thats for greens and t34. but not been mapped.
i have got a genuine t4 turbo but its got a large rear housind sumthing like 0.82A/R with external wastgate, it might sort my power problem but not my lagg problem.
Tabetha i always admire hearing about your spec and how well it performs with efficiency etc, im interesed in the new build. 9;1 comp is quiet high, mind your only running 18 psi so should be fine with low act,s

tabetha

The comp is plenty low enough for my boost level, and will increase low speed off boost torque in particular, which is where it's at 95% of the time, I'm happy with a useable 380-400bhp that doesn't need the engine at 5K for it to do anything, may also go for a 3.38:1 diff.
I had loads of problems when mapping mine, none to do with the mapper or ecu all the car probs, tank then sprung a leak whilst on rollers, then had a injector overheating, then sorted this and the tps then caused problems with such a flat spot that we couldn't drive through it, so needed to swap this, Ł20 for a universal fit, 1 min on laptop to set up job done, and no "cossie tax" on the part, and the pump was "suspect".
It had had about 2 hours mapping when we had to stop, it had a base map already, and when I drove it home to fix the TPS issue it was like driving a rolls royce, the smootheness and pick up was unreal no lag at all compared to before, off boost power was unreal compared with before, it if had stayed at that it was still 10X better than a chip etc, but better was till to come with full mapping.
Dave@emerald didn't charge me for the 2 hours mapping even though had to start over due to it having a new pump(as a precaution) and filter of course, just the regular Ł280(inc vat)(for all three) I had three maps done one was a gentle map for wet driving, one was my play map, one the full power map, due to mileage kept the boost down, in short over a admittedly bad chip picked up 30bhp for 8psi less boost, and ran to perfection.
I don't like the idea of not being able to alter the running charicteristics of the engine, if I never do alter them that's fine but I want a system that I can, that's why I went aftermarket, don't need to use any cossie sensors or even bosch sensors, most sensors can be dialled in with different resistances so can use them from anything nothing hard to get all at your nearest shop.
The only thing I have adjusted is the idle speed when cold, just so it warms up a bit quicker in the winter so I can get in a nice warm car, I put this on the low power map so I can simply flick the switch to go from 1 to the other.
tabetha

WongRS

iTrader: (11)

my t34.48 is laggy as hell too, on a standard engine!
i can cope with it, but my mate has an astra gsi with c20 let in it, and that thing is on boost sooo quickly compared to mine!

martysmartie

iTrader: (1)

I find mine fine, when I got car someone had lowered CR for some reason, I found this laggy, when rebuilt compression was rasied back to standard and now it's much more responsive. I make good boost by 3K. Remember these cars of boost are not the most driveable as with most turbo cars of the age. I think the C20let will probably have a smaller turbo?

Martin

Staffi

iTrader: (1)

Dan,

Can't understand that mate, my T34.48 was just superb, alomost spooled up like my T3 does now..

So when is yours coming on boost then??

Herbo747

I think that it maybe worth going back to basics and checking everything obvious over, where have you had this t34 from, have you checked the wastegate isn't stuck open, thus meaning you got to build boost back up after gear change ect?

KSA-Cossie

iTrader: (4)

Thats strange dan,when mine was on that turbo it was mental quick to spool up.

WongRS

iTrader: (11)

i thought the t3 was laggy as hell too, so i think its just me!
Being in my mates astra just amazes me compared to mine!
i dont mind a bit of lag though, makes the car feel faster!

tabetha

Lag makes it "feel" faster as there is a more noticeable increase in power when it comes in, whereas the non laggy one with the same power IS faster but doesn't feel it!!
tabetha

LHD220Turbo

iTrader: (4)

you should not have lots of lag on a t34.48! my t34.55 was pulling like a train by 3000rpm

forevaford

iTrader: (2)

i did a 13.3 today but the officials wouldnt let me run agen cus i needed a helmet lol.
if im in 3rd at say 5k rpm and i floor it, it still takes a few seconds to make boost, and then its slow to build up, you can watch the boost guage rise slowely, just as it starts pulling hard its on the 7k rpm limmeter. maybe the .48 housing has been ground out to nearer a .63 etc. thats wot it feels like.
im gona put my t4 on then aftermarket ecu, mapping .... job done