Mods to wake the 928 S4 up a little
05-10-2018, 01:14 PM
#31
Rennlist Member
Hi Dan
Great discussion and exactly what I thought needed done when I bought my 89 S4.
First things first you should ensure your S4 is in good health, by that I mean that engine sensors and MAF are all working as they should. Included in that list should be the operation of the inlet manifold flappy.
Without these all working properly the car will loose lots of HP.
With a completely healthy S4 a good approach in order of expense / effort is below. Changing the cams is the only open heart surgery required which could be combined with a water pump change. This first level can get you close to something like a 60 - 70 hp bump
x pipe
headers
shark tune
GT cams
Next level up before forced induction or stroker
higher lift cams than the GT cams
Inlet manifold changes
Great discussion and exactly what I thought needed done when I bought my 89 S4.
First things first you should ensure your S4 is in good health, by that I mean that engine sensors and MAF are all working as they should. Included in that list should be the operation of the inlet manifold flappy.
Without these all working properly the car will loose lots of HP.
With a completely healthy S4 a good approach in order of expense / effort is below. Changing the cams is the only open heart surgery required which could be combined with a water pump change. This first level can get you close to something like a 60 - 70 hp bump
x pipe
headers
shark tune
GT cams
Next level up before forced induction or stroker
higher lift cams than the GT cams
Inlet manifold changes
Please post relevant dyno charts.
Kibort, we, sometimes we all love to argue, but he has done all he can do short of forced induction on the god given displacement he has..and hes not getting 60-70Hp...and I thoroughly believe his ~330 RWHP number, and he;s surpassed what youre going to be doing to a drive to work everyday car..
05-10-2018, 01:38 PM
#34
Pro
So saying you these modifications would net you 48 RWHP does not seem overly optimistic. Someone with these modifications and a dyno run can resolve
05-10-2018, 02:15 PM
#35
My '88 dyno'd 25something to the ground stock and when installed the X-pipe it dyno'd 286, not the same day but same dyno so take that for whatever. Wife's 90 dyno'd 289, bone stock on the same day mine did 286 with with an X-pipe. Wanted to toss an X on there but she wanted to keep it stock. Been damn near 10 years since all that was done so don't remember exactly what my initial dyno numbers were but it was in the 250 range, I remember that because I got made fun of.
05-10-2018, 02:21 PM
#36
Rennlist Member
If you add 50Hp crank, you will see most of that 50HP wheel still.
If you want to argue a few exhaust mods add 80Hp crank, and there will be at least 85% loss to the wheels, then we agree on the _actual_ gains for Exhaust work.
But were not, 80-15% is 68Hp, which is bollocks.
The road to...10-15Hp is "cheap" in the ohh...$300-600 range of breathing mods between the air filter and the exhaust pipe, depending on what you find and how you buy/build things..but the road to 80-150Hp is many thousands to maybe $10k, and is going to need at least a supercharger. Maybe cams plus exhaust..50-60Hp...significant $ still.
More...then stroker and F U money to get there...but a few phone calls and you can get there.
But..an Xpipe and RMB plus tuning..15Hp? Thats actually a lot of airflow for an N/A engine..thats respectable.
05-10-2018, 03:55 PM
#37
Pro
If you add 50Hp crank, you will see most of that 50HP wheel still.
If you want to argue a few exhaust mods add 80Hp crank, and there will be at least 85% loss to the wheels, then we agree on the _actual_ gains for Exhaust work.
But were not, 80-15% is 68Hp, which is bollocks.
The road to...10-15Hp is "cheap" in the ohh...$300-600 range of breathing mods between the air filter and the exhaust pipe, depending on what you find and how you buy/build things..but the road to 80-150Hp is many thousands to maybe $10k, and is going to need at least a supercharger. Maybe cams plus exhaust..50-60Hp...significant $ still.
More...then stroker and F U money to get there...but a few phone calls and you can get there.
But..an Xpipe and RMB plus tuning..15Hp? Thats actually a lot of airflow for an N/A engine..thats respectable.
If you want to argue a few exhaust mods add 80Hp crank, and there will be at least 85% loss to the wheels, then we agree on the _actual_ gains for Exhaust work.
But were not, 80-15% is 68Hp, which is bollocks.
The road to...10-15Hp is "cheap" in the ohh...$300-600 range of breathing mods between the air filter and the exhaust pipe, depending on what you find and how you buy/build things..but the road to 80-150Hp is many thousands to maybe $10k, and is going to need at least a supercharger. Maybe cams plus exhaust..50-60Hp...significant $ still.
More...then stroker and F U money to get there...but a few phone calls and you can get there.
But..an Xpipe and RMB plus tuning..15Hp? Thats actually a lot of airflow for an N/A engine..thats respectable.
You are miss quoting any references to 80 hp also. I have stated a typical drivetrain loss figure covering manual and auto boxes, auto at the high end of the scale.
If you read my post I said x pipe, headers, Shark Tuner and GT cams will give you that additional hp. These are doable modifications which can all be done with the engine in situ. Not cheap but also not SC kit money/challenges.
Arguably if you are to put in cams and can’t get used GT cams then you may as well sling in even higher lift longer duration cams and get another good bump in HP. The roadmap to what mod to make remains the same. Since Dan mentioned only waking up his S4 cams might be a step further than he wants to go, who knows?
Last edited by Marti; 05-10-2018 at 04:35 PM.
05-10-2018, 07:01 PM
#38
Rennlist Member
I am...and you said simply do cams and exhaust..60-70HP. The exh claims were up tp +40, fair nuff, but BTDT.
Ok...do it. If it was that simple...
I dont think youre understanding that exhaust mods are no more than 10-15Hp in ideal conditions...I think..ive done them all, i dyno dang near every -month- because its super convenient and free.
Your money, now...put up dyno sheets.
There are a lot of emotional claims in here about "i can spin tires!" Well...so..not a talll task in any manal trans car. Its just a statement..not one of absolute gain...a chip...move timing a little, and it will both feel better because you want it to, and also because tip in will be a little sharper..but on the dyno..eh, its _really_ hard to actually feel 2, 5, or even up to 10Hp when it's, in proportion, only a 3% gain.
I can go back years, and show a stock S4 auto, then added EIs, then X pipe, then headers...etc..etc..BTDT. Just with ppl would provide hard data when they throw around HP numbers.
Anyone looking to buy something, should be cognizant of asking for the same...
Ok...do it. If it was that simple...
I dont think youre understanding that exhaust mods are no more than 10-15Hp in ideal conditions...I think..ive done them all, i dyno dang near every -month- because its super convenient and free.
Your money, now...put up dyno sheets.
There are a lot of emotional claims in here about "i can spin tires!" Well...so..not a talll task in any manal trans car. Its just a statement..not one of absolute gain...a chip...move timing a little, and it will both feel better because you want it to, and also because tip in will be a little sharper..but on the dyno..eh, its _really_ hard to actually feel 2, 5, or even up to 10Hp when it's, in proportion, only a 3% gain.
I can go back years, and show a stock S4 auto, then added EIs, then X pipe, then headers...etc..etc..BTDT. Just with ppl would provide hard data when they throw around HP numbers.
Anyone looking to buy something, should be cognizant of asking for the same...
Last edited by Speedtoys; 05-10-2018 at 07:29 PM.
05-11-2018, 05:16 AM
#39
Pro
I agree that dyno results are the best measure of gains made due to tuning.
Great you do a lot of dynoing as do other Rennlisters, maybe put up some results or threads of your results to help Dan if he is interested in the modifications you carried out.
There are plenty of threads showing good gains with simply an X pipe and headers to compare types of header/x pipe and possibly what level of Shark Tuning has been carried out. A previous poster saw 250 to 286 WHP
As for me, well this thread is not me or my dyno results. I have a thread covering my modifications and I will of course dyno and share the results but that’s off topic.
Great you do a lot of dynoing as do other Rennlisters, maybe put up some results or threads of your results to help Dan if he is interested in the modifications you carried out.
There are plenty of threads showing good gains with simply an X pipe and headers to compare types of header/x pipe and possibly what level of Shark Tuning has been carried out. A previous poster saw 250 to 286 WHP
As for me, well this thread is not me or my dyno results. I have a thread covering my modifications and I will of course dyno and share the results but that’s off topic.
05-13-2018, 10:48 AM
#40
Nordschleife Master
The first four questions are:
Do you have to pass emissions visual inspection?
How much power you want?
Is the engine intended to be driven at the limit for seconds on street tires or for hours on slick tires?
Is the budget consistent with the answers to the above three questions?
Do you have to pass emissions visual inspection?
How much power you want?
Is the engine intended to be driven at the limit for seconds on street tires or for hours on slick tires?
Is the budget consistent with the answers to the above three questions?
09-05-2018, 11:15 AM
#41
Deleted
Last edited by Geza; 09-05-2018 at 12:12 PM.
09-05-2018, 11:18 AM
#42
Administrator - "Tyson"
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Porsche figured this out, look up the gear ratios of the 89+ cars.
Also, if everything is adjusted properly these cars will drop into 1st gear as you reach speeds below 20mph if the gear selector is in 2nd.
Also, if everything is adjusted properly these cars will drop into 1st gear as you reach speeds below 20mph if the gear selector is in 2nd.
09-05-2018, 11:26 AM
#43
928 Collector
Rennlist Member
Rennlist Member
Go to a long, safe, open spot where you have a quarter mile of road head of you (not a public road, and with no pedestrians / cars around you).
Put the car in 2.
Hold the wheel firmly, and straight.
Step on the gas pedal all the way to the floor till it cannot go anymore.
When you get to 5,000RPM, shift to 3 for a few milliseconds, and shift back to 2.
When you get to 5,000RPM, shift to 3.
When you get to 5,000RPM, shift to D.
Report back.
09-05-2018, 12:46 PM
#44
Administrator - "Tyson"
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