Menu toggle

turbo boost problems

u63af

u63af

New member
I just got my 1990 turbo last weekend. Have to say, it does not feel any quicker than my s2. I have put a boost gauge in the car and it boosts to about 10 psi in 1st 2nd and 3rd and then drops to about 8 psi. In 4rth and 5th it boosts to about 13 psi before dropping to about 9 psi. Anyone had a problem like this? I was thinking that it may be a boost leak or a knackered wastegate.
Cheers
Sandy
 
Sounds like there is something amiss. On boost it should feel significantly quicker than an S2. If it is the car's original wastegate then i'd bet my left kidney that it is not holding boost unfortunately. Boost leaks should be your first port of call with boost related problems. Unfortunately they can be a pig to trace. It might be worth using the search functions to read about all the various ways people have traced boost leaks in the past.
 
Mine did the same when I first had it, dash gauge didn't go past 1.2 and I thought well its a bit quicker than my old S but doesn't exactly set your pants on fire.
Steve Bull had it and took umbrage that I said our Impreza was much quicker so set to work.
It turned out that there was a cracked pipe on the inlet side and the waste gate is properly fubared. They fixed the leaks and installed a boost enhancer they had kicking around on long term loan (cheers Christian). Needless to say they then warned that the suspension wasn't up to the new performance!
It does go rather better now!
One word of suggestion. My bill was quite high - labour is not cheap. I wonder now if I wouldn't have been better off just getting a DPW fitted as in the process of fitting most of the problems would have come to light. Some would still have cost to fix but I would have had a DPW for not much more.
In some ways I was unlucky and I know Christian spent far more time on it than I was charged for - yours may be far simpler but as Scott says if the WG is the original it will be knackered so rather than spending money having it investigated just change it to a better one.
 
I bet it doesn't really wake up until 4k either?

A tired wastegate will stop boost building early, and limit the max boost you can run. Even a good factory wastegate will only hold ~11psi at redline though.

While you're sorting this you can fit a boost enhancer (very cheap but effective) to go with a refreshed wastegate (single port), or a manual boost controller with a dual port.

If you run extra boost - don't forget to run with a decent chip as well :)
 
Yeah, it doesnt pick up til 4000. It does feel pretty quick when it is on boost but it picks up late.

Will this waste gate fit?
http://cgi.ebay.co.uk/TIAL-WASTEGATE-38mm-PURPLE-7-25-Psi-EVO-WRX-SKYLINE_W0QQitemZ390024065058QQcmdZViewItemQQptZAU_Car_Parts_Accessories?hash=item390024065058&_trksid=p3286.m63.l1177
 
I might have that Tial wastegate for sale very soon as it looks like I will end up with two!

But it will need the correct adapter plates. Also be worth getting a MBC to get the best from it.
 
Promax quoted me about 1200 for their Stage 2 kit fitted - DPW, manual boost controller, new chips fitted and optimised.
 
With a DPW you will need chips even if you set the boost pressure to stock via an external boost control system.
 
Mine is stock boost and only hits the overboost on a cold morning when flat out in 4th. I have new chips to fit but the car feels at lot better anyway now it holds 0.75Bar to the redline. Still takes 3.5k revs to get going.
 
ORIGINAL: homesea

I might have that Tial wastegate for sale very soon as it looks like I will end up with two!

But it will need the correct adapter plates. Also be worth getting a MBC to get the best from it.
Click to expand...
Tom, Could be very interested...like everyone else!!
First dibs as they say.
 
I noticed that the tial wastegate is 0.9 bar in that one. I have found this one:
http://cgi.ebay.com/ebaymotors/NEW-Tial-38MM-External-Wastegate-with-Dump-Tubes_W0QQcmdZViewItemQQ_trkparmsZ72Q3a1205Q7c66Q3a2Q7c65Q3a12Q7c39Q3a1Q7c240Q3a1318Q7c301Q3a1Q7c293Q3a1Q7c294Q3a50QQ_trksidZp3286Q2ec0Q2em14QQhashZitem120363247546QQitemZ120363247546QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

I know that this is higher boost but I am wanting to run 1.2 anyway. I was going to get adaptors fabricated or see if I can cut off the flanges from the old wastegate. Doe you guys think that it would work?

Also, is this one a dual port or single port?
Cheers
Sandy
 
All TiALs are dual port. In fact pretty much all proper wastegates are dual port as single port is a poor design.

You don't want a bigger than 0.9bar spring. In fact I might even go lower. The idea is that you can control the boost with some form of boost controller, but you can never go lower than the spring rating, and you ideally want to control it throughout the range you want to use rather than use the spring and then try to introduce boost control if you go a bit higher. This would be especially important if you ever had an electronic boost controller.
 
Fen,
That 1 bar wastegate is going really cheap. I am wanting to run my car at 1.1 bar anyway. What is the downside of having a 1 bar wastegate if I am keeping it at 1.1 bar all the time? I think it is possible to change the spring in the future if I need lower boost.
 
It is very easy to change the spring on a TiAL, it is designed that way. The time consuming bit will be taking it off and refitting it to the car (but that will only be a couple of hours if its still pretty new and the bolts aren't corroded on)
 
As Paul suggests snap it up. Springs are easy to change, but they are surprisingly expensive for what they are I believe. 1 bar should be OK however, just you won't be able to turn the wick down for any reason. Rebuilding the engine and running low boost while you bed things in is an example of a time you might do that. I wouldn't go higher than a 1 bar spring though.
 
I have a 0.8 bar and a Greddy electronic boost controller which gives me three boost settings. Lo at 1.0 bar, Hi at 1.2 bar and switched off gives me the base 0.8 bar.

With the current slippy roads it's been switched off since, ooooh about November :ROFLMAO:
 
Trouble I have with cars is I always want them at their fastest so if I had an EBC i would have it on high all the time. I think I will try and get this one and maybe I wont even need a boost controller then. Although I will have to weigh up making the adaptors myself. I have never taken the wastegate off but I assume that the ends of the wastegate could be cut off and used as adaptors on the end of the tial wastegate. $140 seems a lot of money for 2 flat plates of steel that are drilled to fit.
Cheers
Sandy
 
ORIGINAL: u63af

I just got my 1990 turbo last weekend. Have to say, it does not feel any quicker than my s2. I have put a boost gauge in the car and it boosts to about 10 psi in 1st 2nd and 3rd and then drops to about 8 psi. In 4rth and 5th it boosts to about 13 psi before dropping to about 9 psi. Anyone had a problem like this? I was thinking that it may be a boost leak or a knackered wastegate.
Cheers
Sandy
Click to expand...
Hi Sandy,

A 944 Turbo has very different driving characteristics to the S2, but should feel ultimately faster once you have got used to keeping the revs above 4,000 rpm for maximum performance (under the right circumstances).

The maximum boost of any standard 944 Turbo is 0.75 bar (11psi); in the earlier cars this will fall away to 0.5 bar sooner than in the later (250bhp) cars. Hence, your car's boost characteristics appear correct (allowing for discrepancies between boost gauges and the fact that the car is almost 19 years old).

If you want to be sure your wastegate and boost control system is operating at peak efficiency (which from your description is appears to be), you will need to pressure test the inlet and vacuum connections; check the operation of the wastegate and cycling valve (that is electronically switched by the KLR to direct air pressure to the wastegate control chamber).

Unfortunately, the Turbo does have lag. There are numerous ways of reducing it (and improving performance) and that's another story :)

Regards,
Andrew
 
You must log in or register to reply here.

Posts made and opinions expressed are those of the individual forum members

Use of the Forum is subject to the Terms and Conditions

Disclaimer

The opinions expressed on this site are not necessarily those of the Club, who shall have no liability in respect of them or the accuracy of the content. The Club assumes no responsibility for any effects arising from errors or omissions.

Porsche Club Great Britain gives no warranties, guarantees or assurances and makes no representations or recommendations regarding any goods or services advertised on this site. It is the responsibility of visitors to satisfy themselves that goods and/or services supplied by any advertiser are bona fide and in no instance can the Porsche Club Great Britain be held responsible.

When responding to advertisements please ensure that you satisfy yourself of any applicable call charges on numbers not prefixed by usual "landline" STD Codes. Information can be obtained from the operator or the white pages. Before giving out ANY information regarding cars, or any other items for sale, please satisfy yourself that any potential purchaser is bona fide.

Directors of the Board of Porsche Club GB, Club Office Staff, Register Secretaries and Regional Organisers are often requested by Club members to provide information on matters connected with their cars and other matters referred to in the Club Rules. Such information, advice and assistance provided by such persons is given in good faith and is based on the personal experience and knowledge of the individual concerned.

Neither Porsche Club GB, nor any of the aforementioned, shall be under any liability in respect of any such information, advice or assistance given to members. Members are advised to consult qualified specialists for information, advice and assistance on matters connected with their cars at all times.

Porsche
Lockton
Pirelli
Officially approved
Oracle Finance
WEX Esso
Collecting Cars
Archant Dialogue
Back
Top