930 Boost confusion

[Muzzer911]

I have recently purchased a 1987 930 turbo

http://www.eporsch.co.uk/0101for_sale.htm

It states a BHP of 330. I was under the impression that this model came with 300 BHP. I was told that this was because it had a boost spring at 1.0 bar.

Maybe I'm a bit naive about these things but would this increase the BHP and what exactly does the spring do?

 

[Guest]

Neat car Philip - Congrats

A stiffer Waste Gate spring prevents the waste gate valve from opening too quickly before the turbo can produce boost. This delayed Waste Gate "cracking" improves transient throttle response and allows the boost to increase at a quicker rate.

The standard 930 usually runs at 0.7 bar boost.

1 bar can give you 320-330 but maybe not on a 75k engine!

Take it to a rolling road to find out.

Cheers

 

[Guest]

1bar of boost is ok. and yes you will get better bhp runs, but if you would realy like to unleash the real bhp left in your 930, do as i did to mine! i put a evo fast flow inter cooler,tial wastegate with 1.35bar spring, kkk27.7200 turbo and a hand made "john sleeth" back box free flowing, my 930 runs 420bhp. she would run more but the clutch slips, plus i need to go to electronic injection.[8D]

 

[turbo jonny]

Yes there is alot that can be done to uprate the performance of a 930. But it can cost££££££ and wear your engine quicker.I have had my 89 model for over a year now and am still learning her abilities!
So far i have only succumbed to the 1 bar spring! A bit at a time is my plan.Im more looking at weight saving possibilities to improve handling as well as BHP ( air con is 50kg ) .Not heard of the sleuth back box mentioned before but im looking for a lighter box that also sounds nice - any more info on this one ?

 

[Guest]

hi,
john sleeth, builds drag cars and is renound as the head of his class, he runs a road legal
audi 80 coupe, with 2000 BHP. its mad!!! if you would like him to build you a system let me know, ive run meany different set ups on my 930/turbo, and i disagree about the cost of things try ebay usa. or look outside the box, as john says "its just a engine" and pritty simple at that! he is fitting me a msd ignition system next week, with boost box and timing retard module. dont be affraid of running a breather system eather. the next thing im doing to mine is fitting electronic fuel injectors with a monster mappable brain got all the bolt on parts imported from states for $1020 about £580. abit of vat but i claim that back. one thing i will say my car as never run smoother than when i put a duel cellanoid boost computer on it, it cut nealy all the lag out and took a second off my 0-60 times, the APEX-i dcbc is the best you can set boost in all gears. and it has a over take button that gives you high boost for 5 secs. another thing i tryed was running a fifth injector to give more fuel as the boost increased easy with a ajustable boost switch, well i hope that has helped you. i run my car on most dry days, to and from work, my mods realy do work! if you think old school you will be limited by what you can do to your car, i think a little different thats all!!! DELROY.[8D]

 

[turbo jonny]

Hi , i am impressed at your courage to experiment - do you keep your insurers informed or would they have a fit ! I agree about buying from the USA - ive seen some good stuff on the US turbo club boards and tuning outfits.I am up in the North East and i dont know any good tuners here - i was thinking of getting my car down to G Force or Bob Watson for a check over and advice on modifications.My instinct is to uprate things ( turbo , headers , intercooler etc) when they need replacing.What changes would i see with a john sleeth back box and rough cost please ?

 

[Guest]

sorry its took so long for me to get back to you "bank hols n all that!"
my insurers didnt even blink at the mod's on my 930 thay just wanted to know that i wouldn't be putting nos. on it!!! in fact thay told me that it was a classic, and i quote ("its not like its a mitsubishi evo with wings n stuff on it is it"!!!!!!!!!!!!!!!!!!!!!!!!!!!!)
and i dont experiment! i am so feed up off the way that a few people in the car tuning game keep the 930 held back because they want to corner the market. " MY GOD ITS A ENGINE". old school maybe but dont that mean with the tec. we have today it should fly??? (sorry! me rambling on again).
right, the "John Sleeth system" on my car was hand built and cost me £500.00 i gaind 28bhp and could back the timing off a tad. wich gave me a realy crisp exceleration.
*please note i run my car on shell optimax* and very high meth octain boost. if i dont it runs flat as a fa*t. but thats just me! no reason why you cant run stock 4star i just like my car snappy.
i do alot of work on high power cars give us a call if you like. my work garage number is 01709545164 ask for Delroy
cheers Delroy.[8D]

 

[Guest]

i have just become owner of 930 in the last four weeks, i too have modified car - 1 bar waitgate spring, k28 turbo and b&b headers, a quick question, what are b&b headers?

Previous owner claimed 380 bhp.......going to janspeed on the 27th to find out........have developed a nasty oil leak in the last week oil specs now flying up on the rear bodywork and on number plate , is this serious or just a gasket failure also noticeable is a small puff of blue smoke on start up , was told this was oil residue sitting in the exhaust system - is this possible?

thanks

 

[John_Ward]

Don't know any tuners in North East, but North West has Ninemeister.
Colin knows 930's inside out and has developed many of his own upgrade parts.
Absolutely no quibbles about quality of work from either Bob Watson or G-Force, just a shorter journey!
Rgds
John

 

[John_Ward]

Puff of oil smoke on cold start up is not uncommon; excess oil from turbo scavenge system burns off.
Oil leaks are not uncommon either on 911 engines, and problem can be exacerbated by using thin fully synthetic oils.
Oil drops spraying around behind car are uncommon and should be investigated promptly!
Fingers crossed
John

 

[911 Turbo]

I stand to be corrected but my understanding is that "headers" take the hot gases from the engine to the turbo and on a standard turbo this path is up to six foot in length at its longest point resulting in loads of heat loss/gas velocity. I would imagine that your "B&B headers" are a modified set of "headers" that shorten this length by taking the gas a shorter route to the turbo. This would result in a reduction in turbo lag and more power as the exhaust gases to the turbo have a shorter path to travel and hit the turbo sooner and with more heat/velocity.

 

[sawood12]

Don't you guy's run Dual Port Wastegates? They don't need springs to operate meaning they don't get weak over time. You can also adjust the boost whenever you want.

 

[Tankman]

I don't know much about the intracacies of tuning and wringing the most out of engines but there are some really excellent specialists out there. I didn't have to suffer the expense of the mods on my car which although shows as a '78 930 on the logbook is in truth only 12 years old in engine terms. JZ and JAZ are the culprits and having recently dynoed at 510BHP peak at just under 1 bar (see "Shock Result at Silverstone" http://www.porscheclubgbforum.com/tm.asp?m=130360 ) there are lots of possibilities . . . . . []