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OZZY_C

Gt4 St185 How To Mod?

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HI guys, i have a standard ST185 the only mod it has is a baileys dump valve. I want to start slowly and mod it up abit and make it into my little project. were should i start with the mods best ways to get bit more BHP....

i want to do it up slowly over the next couple of months and take it down to santa pod for some fun :)

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first off give it a thorough service, best to start on a sound base.

if the dumpvalve is of the stmospheric type get a recirculating one, atmos DV's tend to cause fuel consumption issues.

performance type panel air filter, decat and an exhaust should get everything brerathing nicely (2 1/2" restrictor may be needed if you go for a 3" exhaust and decat to prevent boost creep)

next up an electronic boost controller although id stick a metal headgasket in first and a set of ARP head studs as the stock head gasket is a weak point. boost set to 1.0bar (14.4psi) and thats about it without spending money on an engine rebuild or a turbo.

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Hi mate, thank you for your responce, do you think i should save and get it all done at once or should i do it bit by bit as in start with the air filter and then get the decat and exhaust in a month or two? also how much do you think im a looking at for the mods you mentioned?

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first thing I would do is dump the bailey's dump valve, they are notorious for leaking air and causing the fueling issues that dawsey mentioned, an HKS SSQV or something of comparitive high standard is the best to go for if your wanting to keep it venting to atmosphere.

then give the car a proper service, check when the timing belt was done and ensure the brake fluid is fresh (DOT5.1 handles higher temperatures best) and brakes are up to scratch, there's nothing worse than a fast car and no brakes. If the timing belt hasn't been done save your pennies, it's a big job and you'd be best getting the water pump and head gasket changed for a metal one with ARP studs, to keep the head pinned down tight.

for an air filter I'd highly recomend going for an uprated panel filter (such as a Blitz SUS) rather than a cone, this way you keep it sheilded from the temperatures of the engine bay at minimal cost. There's a resonater box in the inner wing on the intake, remove this, it's a major restriction in the intake and is only there to reduce induction noise.

next on the list is the exhaust, De-cat pipe first, make sure it's either ceramic coated or lagged to keep engine bay temperatures down. for the rest of the exhaust generally go for a 2.5 inch system as this keeps the boost under control, if you end up with a 3 inch system there are 2.5inch restrictor plates available to keep the boost from creeping.

once you've done your intake and exhaust your turbo won't likely last long, this is the unfortunate thing about these cars, they're no spring chickens, it'll be the Oil seals. This is purely down to the turbo being able to spin faster than it has done before, so a re-condition is the best bet, buying a second hand turbo is a gamble as the same thing could happen again, if it's re-conned you know it's all good for turning the boost up.

it's not normally advised to upgrade the fuel pump on these cars till your pushing a lot of extra power but with the ages of these cars now I'd stick in a walbro pump to ensure fuel delivery is there when it's needed

It's an expense but I'd also look into after market management, don't believe what you hear from back door tuning shops (read ebay if you like), these ECU's cannot be chipped, if your going for a piggy back don't get a uni-chip. Alot of ECU companies are now selling entry level standalone ECU's but your still talking £1000 minimum once they are fitted and mapped

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gtforbes thanks again for your helpful mail. in regards to the HKS SSQV do i have to get one that fits the GTFOUR or are they universal and work on all turbo cars? also will i still get the PSSSSHHHHT sound when gear changing?

in regards to the timeing belt i am not sure when it got changed or anything its a jap inport and it says on the clock it has done about 90k klm. one of my mates told me this has a none interfearence engine so if the belt goes it aint to much of a big deal? im not sure as i do not no to much about cars all i no is the GTFOUR is the best car i have ever had i love the way it looks and pulls plus the insurence on them aint bad.

in regards to the air filter and exhaust should they be done at the same time as i would need to save for a bit to do them togeather or can i get away with doing the air filter first then getting the exhaust like 2 months after?

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The hks will give you a mush better sounding dump, you can get different attachments for fitting.

Your mate is right, the engine is a non-interference engine but prevention is better than cure, it's a royal pita to get a tow to a garage and you'll need to wait till they get to it, plus if the belt goes it could damage other bits of the engine when it spins off.

The air filter you can do at any time, sooner the better. Just remember to remove the resonator box from the inner wing, this will give you a good little bit of extra power for free.

Have to agree, the gt-four is a great car, and it can be made an even better car with the correct mods

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The resonator box you mention,any picture of this,or exact location,does it sit low down inside the wing?

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It's in the inner wing, I'll get a picture of one tomorrow when I'm in work as I've just removed one for a customer. you can either yank it off and leave the mounting bolts in place or remove the front bumper to get the two that are behind it

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I would be looking at brakes and suspension before engine mods TBH. As a side note, look at how your insurance premium will increase......

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It's in the inner wing, I'll get a picture of one tomorrow when I'm in work as I've just removed one for a customer. you can either yank it off and leave the mounting bolts in place or remove the front bumper to get the two that are behind it

Thanks mate,pictures always help.

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if i was to put the K&N air filter on and remove the existing box would i need to inform my insurance?

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Yes, not to mention build an enclosure to prevent it sucking in hot air

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resonatorbox.jpg

I've circled the bits that pop off, the screw can be ripped off or you can remove the bumper to unscrew it. It'll do no harm ripping it off as the box will be straight in the bin anyway.

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if i get a blitz panel filter will i still get the good induction sound that i would with a cone?

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It won't be as prominent due to being enclosed but it will give the better performance gain. Have you removed the resonator box yet?

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Hi Thank you for your responce, no i have not remoeved anything yet just trying to work out what will be the best option for me. its not just about the performance i like the intake sound so would i be best off with a cone type? also not sure if you see my other new topic i have started but i got the HKS SSQV and its really not working it either kills the engine or when i tighten it it does not blow off at all?

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If you remove the resonator box first and see how that sounds then take it from there. Will go look at your other thread now

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Hi Gtforbes, should i remove the resonator box now? i do not have either the cone or panle filter i want yet? how will this work on my current/standard air system i have? thank you for checking my other thread i appreciate your help mate.

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Yeah just remove it now and see how you like the induction noise before buying any filters

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ok mate i will try and remove it tomorrow morning. could you please tell me exactly were this box is located as i dont want to remove the wrong thing lol.

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Ok mate will give it ago in the morning. Tried that hks ssqv again tonight I think there may be a problem with the valve and not how I fitted it as if I loosen the adjusting screw at the back and put my hand over the fronof it then it works as it should but when I move my hand it stalls.... Then if I tighten the screw the engine idles fine without me having to put my hand over the front of it but the it don't blow off like it should it doesn't do anything. It's shouldn't do that should it?

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Sounds like its either broken or in need of a service. If your confident take it apart and clean it up, if not I wouldn't

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