Engine build progress

[TTM]

I ordered a Lindsey exhaust. It may not be the last word in terms of perceived quality but at least I know what to expect in terms of noise level and what adjustments are needed. Sly coated his before we installed it and it has been holding together better than we expected now for several years, in all kind of weather including winter with very salty roads. I looked into the Fabspeed but I didn't really like the sound I could hear on the various videos and, more importantly, they don't make it with a center resonator. A turbo without a center resonator is in my opinion impossibly loud. Sly's was before he added one, now it's tolerable. I will be reusing my SPS turbo. I won't feel like going into the hassle of modifying the exhaust for a GT turbo (or any other turbo that doesn't have the mounting pattern of the KKK turbine) until I will know how much power the SPS turbo is capable of. More to the point, I like too much the way it performs to justify risking modifying the power display. Not only does it feel like it should bring me not too far from 400bhp/400lbs.ft @18psi when I have the bigger exhaust fitted and added some ignition advance, but it also does feel at one with the engine. I also now use a brilliant piece of ECU and it should greatly help me extract most power out of the engine. Bob, you may want to send a PM to Sly for the intercooler, I think he bought it off ebay. Nick, you sound like you will be sticking with the Vitesse turbo? Edited to add : just noticed this thread is 3 years old... How time flies [>:]

 

[nick_968]

Thom My car has an exhaust with no centre box and its not loud at all. I guess they are all different. I am only using the Fabspeed front pipe as they do not sell a 968 rear section to go with it anyway. Custom backbox probably from Powerspeed here in the UK means I can tune the db level so hopefully it will be ok. Re the turbo one of Simons turbos is top of my list and now I have given up on the Garrett full install due to being let down by the US vendor who was going to kit me out. I have also run out of funds so the mission is to complete the install and a few other bits to make it all perfect and as soon as I have the funds I will order up a turbo similar to yours.

 

[JarmoL]

Sorry to hear about the problems with the vendor Nick. My situation isn't much better with the GT turbo.. I installed it and went to MOT station to have the annual inspection done.. And what do you know. The inspector spotted polished engine mount and intercooler with the new shiny Garrett and heat wrapped crossover/ downpipe /3" exhaust combo. [] So he deemed my car illegal. It was in his opinion obvious that the power output had been raised enough to not meet the original emission values anymore(Can't blame the guy really). So I either had to deliver him a proof of the emissions and the engine power.. or go back to my old KKK setup. Because the required emission tests are very expensive and most probably non achievable with my set up I decided to install old parts back. So I drove about 15 km's with the new set up. I thought the new turbo felt great. [] And so went the motivation to work with the car. I am now considering a GT3. []

 

[TTM]

Nick, I'm sure that even with the Vitesse turbo you could get some quite good performance... Actually you already have, you mentioned 400bhp in another thread if I'm not mistaken? I feel pi$$ed off for you Jarmo! [] Is your VIN blocked through the MOT system or can you try another MOT station? I want to believe you can work your way out of this.

 

[nick_968]

Its not the hp I am worried about, it makes over 400 easily. Its the midrange torque. It has a number 10 hotside which while good for backpressure and top end power is slow to spool so it feels very laggy and not what you want for a street car. For a track car that spends its life above 3500 rpm its very quick but thats not what I am looking for.

 

[333pg333]

I'd be expecting a PM between two of the last 3 contributors on this thread...excluding me. []

 

[Sly]

Some pics of the new intercooler []

 

[TTM]

ORIGINAL: 333pg333 I'd be expecting a PM between two of the last 3 contributors on this thread...excluding me. []

As I said I'm sticking to my turbo []

 

[333pg333]

ORIGINAL: TTM

ORIGINAL: 333pg333 I'd be expecting a PM between two of the last 3 contributors on this thread...excluding me. []

As I said I'm sticking to my turbo []

Well that leaves the 2 others....[]

 

[333pg333]

Oh, and fwiw, without being able to offer any quantifiable data except via seat of the pants, I'd have to say that there is a case of diminishing returns when going up in exhaust size. I've thought this since back in the 80's with a turbo VW Golf. It just 'seemed' that you could go up in diameter and after a point, you would lose response from the turbo. There is the school of thought that the best form of exhaust would be none at all...but I'm not so sure about this. I know my previous 2.5L with Garrett GT3076 .82 and large 3.5" - 5" exhaust felt like there was a bit of lag even though you could clearly hear the turbo spooling quite early. Going up to a larger cam would also have helped shift everything across to the RHD also.

 

[TTM]

Just thought I would mention that Sly has seen a significant gain in engine responsiveness and smoothness since he fitted the large intercooler. The car feels like it makes a bit more torque earlier, and that's not a placebo effect. This, and he is able to run about 2psi more to see the level of knock activity he saw with the standard intercooler. This tells me that my turbo + SFR intercooler should perform even better when I have the 3" exhaust fitted... Can't wait! []

 

[333pg333]

Sounds like you're lucky just to have the SFR product in hand Thom. You know the overall feeling while reading this last page is of seemingly constant troubles that most of us have gone through just to get to this point. I know it took Thom a long time and a healthy investment just to get to where you are now. Jarmol is going through a minor nightmare. Nick has had consistent problems with people not following through. I could fill 30 of these pages with my travails....you think I'm joking don't you? [] Seems to be par for the course when you mod these cars. Guess it's such a small puddle in the ocean of cars out there. Lucky we have any aftermarket alternatives at all I suppose....but damn, it really gets draining after a while. Anyway, good to hear that you've made some great progress Thom and are enjoying your car now. I'm sure the larger exhaust should make a nice addition to your great car.

 

[TTM]

Oh yes, it's a rather long and painful progress, and looking how far you have gone in mods I can only dread to think how much you have spent [&:] The problem with people like me who do this as a weekend hobby and who have no academic engineering background whatsoever in piston engine design is to find what works between what other owners report, what vendors pretend and what actually works - of course, ego tends to push you to go your own way, makes you put together your own specific exotic set up, adding more difficulty to the task. I want to believe I haven't wasted "too much" money in the process though, and hopefully the larger exhaust will happen to be the most significant part the puzzle has been missing from the start. I have been enjoying the turbo a lot lately... probably because it's been staying in Sly's garage since July and because I have had a ball with the S2 which has performed like a dream during the holidays on beautiful country roads in the south of France [] Everytime I take the S2 for a long road trip it blows me away how good a road car it is. With the SciVision MAF and some minor suspension tweaks it becomes and fantastic GT and an even better all round car. I did what, about 3000km in ten days and it hasn't missed a beat. Hasn't even drunk a drop of oil, never overheated in the horribly hot weather we have seen in the last weeks - we saw 40°C in the shade in Ardèche...! - even with the engine working hard with the A/C on, it returned a staggering 30mpg. I am in such awe of this car that I want to be buried with it...! I think I'm going to budget for a special gearbox to make the turbo more civilised, now that I've got throttle-based boost control with the Vi-PEC ECU it feels almost manageable as a normally-aspirated engine and shorter gear ratios should make it feel like a "super S2" even more. The guy I sold my Moton/JRZ set up to is a Rally/Hillclimb specialist and has done a pretty interesting job on a 968 gearbox for his 951 - some more food for thought...!

 

[DivineE]

ORIGINAL: 333pg333 I could fill 30 of these pages with my travails....you think I'm joking don't you? [] Seems to be par for the course when you mod these cars.

No I really really dont! I read this and sighed with the memories of the years 'litterally' spent suffering the woes to make/keep my 944 projects. Well done all of you for sticking at it!

 

[nick_968]

You have got to love this thread. Its like the War and Peace edition of 951 modifying!! My car is almost back together now for the nth time with another set of factory headers that I sourced that are in very good condition. All seemed to bolt together well and lined up ok so fingers crossed for a nice tight pre turbo seal. Also pulled off the old crudded up 951 oil cooler that somehow got bolted to my car during its original install and took the oil housing off my original 968 engine to allow me to fit a nice new 968 oil cooler which cost mega bucks from Porsche! So that should be another weak link eliminated from the chain. Looking forward to running her up again and getting to the dyno. As soon as funds permit I will be looking to install an SPS turbo or something similar to Thom. I am also looking forward to installing my new Fabspeed 3 inch front pipe and with it a custom section that is to be made for the rear. Pat I hope your going to get your parts soon and your project gets moving, literally!

 

[TTM]

Nick, looking forward to hearing positive results with the new headers. I suppose you have 944S2/968 oil thermostat housing fitted with the 968 oil cooler? Or did you modify the lines?

 

[333pg333]

Ha, I wish we were all able to get together and swap stories over a few beers or Burgundies. Perhaps next time I'm in the U.K. we can get Thom over the Channel. Thom I am very interested in what your friend has done with the 968 box and what you are thinking? I stuck with the stock gearing as I ran out of time and had no dyno charts to refer to in making any custom gearsets up. Still, I've had people give opinions for and against stock 968 gearing with a turbo motor. My friend Sean is running on the track tomorrow with his newly turbo S2 motor in his 951. He has a 951 gearbox with an S2 Ring and Pinion also. This give similar closeness of gearing to the 968 so it will give a glimpse of what's possible I suppose. I will get some in cabin video and upload it to Youtube by next week. Nick, finger's crossed that this exhaust seals up perfectly and you can move on. Our cars spend too much time off the road!

 

[TTM]

Well, when I have the exhaust installed and the car fully tuned to run 18psi, I will certainly be more motivated to do a little tourist trip in the UK and take a day to put the car on the rollers if we could arrange something together. I'm sure Sly would be interested as well. Pat, I think I am one of the few who repeatedly said to you that 968 NA gearing would be too short for the performance of a 3.0, but I think I will have to eat my hat on this one. I must admit that if the 968TRS ran the 968 NA gearing, then it must have been not completely too bad for track use. It's good feedback to know that the S2 R&P works well in the 951 gearbox, as after lots of miles in my S2 I think it's very well suited to road use, more so than the 968 NA gearbox. Looking at a gear diagram again suggests that perhaps a good compromise would be to use a 968 NA gearbox with the 5th and 6th gearsets from the 968 turbo S - giving about the same three first gears as the S2, and 3 higher gears with the 6th one being sllightly taller than the 951's 5th, which is what I've wanted anytime I have done high speed runs. I have just read your post again on the Pelican forum and the guy has modified his 968 gearbox actually in a similar way to yours.

 

[MarkK]

Is the 968 gearbox more delicate?Deffo feels more lightly built to me?Can it take big power?

 

[TTM]

Bearings and some important parts are beefier on the 968 gearbox, should take at least as much power as the standard turbo gearbox but bearings shouldn't wear out and get loud as quickly.