Durability Vs. Power in modding G54B

[86TSiGuy]

OK, so after reading (and saving) for six months I buy an 86' TSi. It's red, perfect interior, 75,000 miles, but it turns out... we needed to replace the clutch, front u-joints, and suspension components all around. No problem compression test is spot on for all 4 cylinders the turbo is in great shape no noise from the valve train or timing components, it appears someone previously did a really nice job welding the exhaust manifold back together but it actually looks pretty solid. Now I've got $2000 and a month to start in on the G54B before I put her on the road. Here's the thing I want to produce some power gains but without compromising any durability. Now anybody who's spent five minutes in this forum alone knows there's alot of ways to go about it. I plan on putting more cash in later in the spring. For now though I want to bulletproof this thing as best I can. In the end I want to produce about 260hp@5500 and 390lb/ft@2500.

 

Stock 12a with wastegate, bpv, and braided oil and coolant lines at 8-1-psi? / Or is the 12a not worth working with?

 

I think I should replace the head right off the bat, whats the best casting for my money? Should I bother to pay for porting now? Are HD springs worth it if I don't do the valves, guides, or cam?

 

I'd also like to do a full catless 2.5" turbo back exhaust, as the car isn't required to meet emissions here but it's a lot of cash. Is it worth it to do just the manifold, down pipe, and b pipe to eliminate the cats?

 

If I don't expect too much in the way of power gains right away should I do more than just an 86' FCD and rising rate regulator to the FI system? Or is that useless without other work? And if so should I do an injector and pump upgrade, or an AIC system, or go full on MPI?

 

Anyways long post I know, thanks for reading this far. I'll take any input I can get. What would you do first, with $2,000 and a month?

[Technology]

You'll never get those numbers with a 12a.

[86TSiGuy]

You'll never get those numbers with a 12a.

 

OK, if I want to put out about 260 at low psi then which way would you go? 16g? And would you do the fuel, spark, intake, and exhaust work first or start with the turbo?

[creepin87]

You'll never get those numbers with a 12a.

sure he can! Multiport :eek1bluegreen:

[BlowinUp54B's]

Go MPI if you have 2 grand to spend.. It will be worth every single penny + like alot more.

[Scotty Dont]

ya just go mpi off the bat but make sure everything is up to par first

[86TSiGuy]

Yep, everything is up to snuff to start with. What's the best MPI setup? Or should I buy a manifold and fabricate myself? And would you swap out the head first for a non-jet casting? I understand I cant do everything with 2k I guess I'm looking for where to start and since It's going to be my daily driver I dont wanna just strap on a T3/T4 turn up the boost and see how hard a beating the stock internals will take. I want to do it right.

[TainterRacing]

Its my old web page here has some good info. You can have close to what you want with a 12a but it will not last the turbo will be over spinning cant go mpi with less then about 3500 I would say and that's if you do every thing your self. It can be done for less but I am trying to be real. I wish you were closer I would try to give a hand

 

I would put a 16g on new larger IC pipes and the free cheap mods (2.5in ex) and you should get the power your looking at with about 15psi 260 is about the max the stock fuel injection will safely do any how. That could well be done with your 2K and in a timely fashion as well.

 

old T-Racing.com

[86TSiGuy]

I would put a 16g on new larger IC pipes and the free cheap mods (2.5in ex) and you should get the power your looking at with about 15psi 260 is about the max the stock fuel injection will safely do any how. That could well be done with your 2K and in a timely fashion as well.

 

old T-Racing.com

Thanks man I appreciate that.

 

OK, so I think I'll get a 16g, all 2.5" intake plumbing, 2.5" turbo back exhaust w/o cats, BPV set to say 12-14psi, 86' FCD, and a wideband O2 controller.

 

I know it won't get me 260 unless I turn up the boost, but I plan to put more cash into her later this year and I'm going for durability as well. The 16g flow charts look good at 12psi, granted even better at 16-20 but I'll feel better after I take the block down and rebuild in the spring.

 

Question:

You said the stock 86' FI System is good safely to 260hp, does that mean there's no need to do injector, MAS, pump, regulator or ECU upgrades?

[TainterRacing]

I am not 100% sure the 86 will I know a 88 or 89 will support that much. But I bet if you added a fuel pressure regulator on your 86 and add a few psi to the fuel should be all right I bet.

[Funky Phil]

Walbro 255hp

2 GOOD green injectors

MAFT or SAFC

Good thing about the MAFT is it dumps the stock MAS whereas the SAFC uses it.

 

I would get the S16G or an Evo 16G. Any larger Id go to something with a bigger turbine like a T3.

 

Look up Bad2Rass. He did a build on tbi with a T3T4 and MAFT. put down like 305whp.

[Technology]

If you have TBI, I'd only use intercooler piping as big as the inlet to the throttle body.

 

And if you get a 16g, why not just make it a super 16g or "big" 16g (same thing). they flow a bit more air than a regular 16g.

 

I was going to edit my first post to explain some more, but I left my computer for a long time and forgot what I was going to say, so I closed the window, lol.

[Funky Phil]

Buy this NOW!!!

 

http://www.starquestclub.com/forum/index.p...c=81690&hl=

[86TSiGuy]

Thanks everyone for all the help, You've all been awesome.

 

After looking at the s16g, it of course looks like a better choice for the very minor additional cost.

So let me run this by you:

If I replace the head with a non-jet casting (light port and polish) but stock valve train except for hd springs, and the bottom end is stock. Then I bolt on the s16g, 2.5" turbo back exhaust, new plugs, wires, red coil. Then I set the boost to something reasonable say; 12-14 psi, what are the chances I'll hurt anything under a hard pull? Not that I plan on abusing it, or running the car at the track but If I spend all this money importing her, fixing her up, and upgrading her and then I break something and she's off the road until a rebuild my wife will kill me. Any particular setup advice concerning durability?

[Shelby]

if it was me ,i'd get a magna MPI intake , a MS ecu , now i have what i need to start with,, as money is avaliable i'd do the 2.5 exh,,then a 16g ,, from that time on i'm set to make as much HP as my pocket book will alow,,and nothing spent on parts that i later won't have any use for

beleave it or not you can do 225 hp, 250 hp or 300 hp on the same MPi set up ,with a larger turbo and a few simple changes to the fuel map

 

i'd say 225hp may even be posible with the 12a @15 lbs boost with a magna and a 2.5 " exh system

 

any way the reasoning being spend the $2k where it will do the most good and not have to replace any part of what you bought later

[Scotty Dont]

Buy this NOW!!!

 

http://www.starquestclub.com/forum/index.p...c=81690&hl=

 

 

x2

[86TSiGuy]

x2

 

I'm looking into it for sure, I all ready reply'd for pic's. What else do I need to install that w stock 86' intake stuff. I'm definitely going to upgrade my ovcp and intercooler plumbing anyway, and most likely if I do this instead of MPI I'll get a RRFPR and walbro pump, but I saw some 850cc injectors on e-bay too? And shpuld I still use a wideband O2 controller?

[Funky Phil]

Always geta wideband.

[mstieg]

Always geta wideband.

 

Agreed. I know it sucks to drop $200 on what seems to just be a freaking gauge, but it's very helpful and you did ask for reliability. Your stock fuel pump should be okay if you keep the boost at or below 15psi and don't turbo it bigger than a small 16g.

 

Personally, I'd say go 3" exhaust as your very first mod. Can do complete for less than $400 with muffler if you install it yourself. The 2.5" is fine, but 3" flows even better and doesn't get much louder if you get the right muffler.

 

Make sure your stock injectors are good with the free tests (spray pattern, and resistance check), and get em professionally cleaned if they're in question. Check the battery cables and grounds (both body and engine block)

 

If you go to a 16g or super 16g, it should be cheaper to send yours off and have it rebuilt/upgraded...unless of course you need it on the road as a daily driver.

 

Unless you know what you're doing, it'll be fairly tough to MPI quickly and for under $2k.

 

don't get yourself too much power or you'll need to pay for a clutch. ha

[Shelby]

Unless you know what you're doing, it'll be fairly tough to MPI quickly and for under $2k.

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and why is that so ,$500 for intake,, $450 for ecu , $250 for injs,, I'd think you can do the rest of the ic pipes for whats left and the 2.5" exh,

 

and dollar for dollar the hp gains from MPi is more then from the 12a to a 16g

 

but go ahead and go the boost junkie route :biggrinumbrella1:

[86TSiGuy]

Ok, see this is how I got confused...lol I've got about 2k minus of course a new head casting, because intake and exhaust gains aside all that air has to pass through the head for it to matter plus I'm worried about the damn thing cracking or eating up a head gasket. Which leaves we'll say $1,500 and as stated above means I can get an MPI setup OR a s16g w/ turbo back exhaust.

 

The question is which is a safer place to start ( again I'm not concerned with the bigger of the two gains as more upgrades to come later ) A bigger turbo sucking through upgraded plumbing and exhaling through upgraded exhaust but fed by the disappointing 86' TBI, OR the stock turbo breathing through upgraded plumbing and fed by MPI exhaling through stock exhaust?

 

And sub-question: How much custom work is required to upgrade to MPI? I've read alot of threads here about MPI swaps and it seems everybody goes about it a little different but they all have some pretty nasty headaches? It appears no one makes a bolt on manifold with fuel rail and injectors. It seams that a MAFT setup is more bolt on friendly but I realize not nearly as useful as a full MPI conversion, and no I do not want to replace parts twice.

Edited October 7, 2008 by 86TSiGuy

[speedyquest]

just my 2 cents but...

 

as long as you are making sure your fuel system is up to par with your turbo size, and that you dont turn the boost up past where you start detonating due to the "ceiling" the stock tbi setup has, you should not have reliability issues. from everything ive read the stock internals are strong, therefore id assume your going to get to the point where you cant keep a consistent air/fuel ratio before you have a chance to destroy the bottom end with horsepower. as for my suggestion to you, i would buy a decent duration cam(under 284 due to idle issues), use arp head studs, maybe even o-ring your block or head (i know people have different thoughts on this), and use a decent head gasket.

 

again just my opinion, and i am by no means a starquest guru...

 

allen

[Funky Phil]

If your looking for only 250-260whp max you should be fine as long as you dont get cheap and cut corners. If you say you motor is good to go including your TBI you will be fine on tbi with either a MAFT or SAFC. And as long as your smart and put the right parts together you will be happy. But dont expect to make 260whp while only dropping $1500 unless your gonna cut corners and go straight to spray.

 

Just need to ask yourself if you intend to go MPI in the near future. If you do plan on it, make sure you buy parts that will cross over to save money in the end.

 

phil

[Caliber308]

Marnal cylinder head and bolt on mods. If you want to go beyond that, it's a lot more money

 

CALIBER 308

[Indiana]

simple things done to the head, OS valves and HD springs, mechanical rocker arms, exhaust enlarged if its stock. Gauges, good clutch, struts and tires. Even a stock intercooler and TB still works save the $$ for the items that you'd likely not change later on. Forget MPi you are way short on $$ and experience at this time. If you get the motor out for the clutch and you have to put a head on it you should replace the timing components, remove the BS and have it balanced and ad up what you have left, if any to get it balanced and replace the rings and bearings and a gasket set at the same time. Your oil pump will be fine don't waste money on a new oil pump for a motor that was fine before. If you have the head already the rest will cost you just under 2000.00 if you shop wisely. What you'll end up with is a reliable engine and platform to build on. No sense putting $$$ into a car with a tired motor and expecting much from it you do not know what its history is and what its condition is from just hearing it run it may be ready to go at any time so get that part over with in the beginning.