Show full size 924Board.org
Discussion Forum of 924.org
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 
 Technical FAQ924 FAQ (Technical)   Technical924 Technical Section   Jump to 924.org924.org   Jump to PCA 924 Registry924 Registry

supercharger conversion pictures
Goto page Previous  1, 2, 3  Next
 
Post new topic   Reply to topic    924Board.org Forum Index -> Performance Upgrades
View previous topic :: View next topic  
Author Message
leadfoot  



Joined: 11 Dec 2002
Posts: 2222
Location: gOLD cOAST Australia

PostPosted: Fri Apr 29, 2005 5:25 pm    Post subject: Reply with quote

I have not had the time recently to hook up a laptop and check the ignition mapping but think of it not so much as having to retard buit as how much advance can you run. The more advance the better the engine will perform.
Boost is built up almost instantly, by the time I get off the clutch at 1300/1500 and apply WOT maximum boost is seen by 2000RPM. The time difference between these two RPMS is negligable.
Drivability, economy and longevity were all factors when I designed this system, although ease of installation is another story. Even though the system looks simple I can tell you I have spent countless hours measuring cutting and fitting up the main parts. There's alot of work involved in making sure everything is aligned and clearances are obtained.
As for high compression low boost, well I've increase cam timing to accomodate a little static compression, read up on the "miller cycle". This allowed me to have my head modified for N/A before the charger was bolted on, the bottom end has not been touched, as it didn't require the service yet and therefore I run with the higher 9.3 to 1 pistons.
I'm also taking into account the driveline and gearbox which I don't want to destroy. If I had the downtime I would get both shotpeened and nitrided for incresed reliability.
Well if your worried about to make boost down low then use a bypass valve similar to that of the MR2 design. It allows the bypass valve to be open when boost is intially applied, it then gradually closes so that boost is applied gradually. It has full boost coming in at 3000RPM from memory.
It also incorporates a blow off valve that limits maximum boost.
Do a search on "SC12" and look for the pages on the MR2 owners forum.
Might take a bit to find the right one but there is also a mod that allows the maximum boost to be set at 10psi by way of vaccuum routing I believe. This may solve your problem.
Leadfoot
Back to top
View user's profile Send private message Send e-mail
endwrench  



Joined: 07 Dec 2002
Posts: 1629
Location: Victor, Montana

PostPosted: Sat Apr 30, 2005 5:06 am    Post subject: Reply with quote

leadfoot wrote:
Even though the system looks simple I can tell you I have spent countless hours measuring cutting and fitting up the main parts. There's alot of work involved in making sure everything is aligned and clearances are obtained.


Hey, don't get me wrong. I in no way ment to imply what you have done was easy or simple! I can easily see how much work you have done! I probably have 8 hours in just building the blower hat for mine. Everything is custom fit. I will probably end up with 12-15 hours into building the blower intake. Then the drive system! I like your setup by the way. The work I have ahead of me is a little mindboggling. This is why I am tring to be realistic in saying I wont be "huffin" till the end of summer or fall.

So 3lbs of boost doesn't need any retard yet. Even with the high compression you are running. This is good. It will be interesting to see what 6-7lbs will need. Do you remeber what your "total advance" is set at now?

Near instant boost at such a slow blower speed is great news. I hope to have the same.

Thanks for the tips on looking at the MR2 setups. I will research this closely. I don't always use the resorces of the internet to my advantage. It can be a little frustating sometimes ferriting out the actual info you want. If this information works to my advantage I may try blowing my current motor with high compression (9.5:1) before bolting on the turbo head or building another motor. This also depends on your results with the higher boost.

Todd
Back to top
View user's profile Send private message Send e-mail
simsport  



Joined: 06 Nov 2002
Posts: 573
Location: UK Warrington

PostPosted: Sun May 01, 2005 6:23 am    Post subject: Blower Plan Reply with quote

Well, we have a spare good bottom end and so we have decided to turn it into a 2.4 running 9:1 compression ratio and keeping our venerable Eaton m62 supercharger.

We are going to do this over the season when money allows to start next season with a car for next class in the championship.

Estimate is around 250-60 bhp with similar torque.

Crank and sump need mods , will use Golf rods and big ends with the correct JE or Ross pistons.

Cant wait!

Cheers
Simon
_________________
Blown is always best!
Back to top
View user's profile Send private message Send e-mail
endwrench  



Joined: 07 Dec 2002
Posts: 1629
Location: Victor, Montana

PostPosted: Sun May 01, 2005 8:29 am    Post subject: Reply with quote

Sounds mighty nasty!!

Can you run race gas?

Todd
Back to top
View user's profile Send private message Send e-mail
leadfoot  



Joined: 11 Dec 2002
Posts: 2222
Location: gOLD cOAST Australia

PostPosted: Sun May 01, 2005 6:20 pm    Post subject: Reply with quote

Nice one simon, that extra power should put some rubber on the roads...

In regard to ignition advance...well to give you an idea of what it's set at...

I looked at my old ignition map on the computer and it seems that the timing pegs around 31 degrees at 50% load at around 3000RPM. This is almost identical to the new map from what iv'e read off the hand controller. This increases when there is less load to around 46 degrees 3000RPM.

On the new map more advance has been put in earlier but only really a degree or 2. Idle timing is now at 16 degrees 0% load at 1000/1100 RPM.
Idle is slightly higher that normal due to the idle temperature compensation being a little off. Easy enough to tune up though.
When I get the time I'll post up the old and new ignition maps.
Leadfoot
Back to top
View user's profile Send private message Send e-mail
endwrench  



Joined: 07 Dec 2002
Posts: 1629
Location: Victor, Montana

PostPosted: Mon May 02, 2005 2:07 pm    Post subject: Reply with quote

Am I correct in remembering you tuned both motors on the dyno? Both fuel and spark? Did they use any detonation detection equipment or just tune for best power?

Todd
Back to top
View user's profile Send private message Send e-mail
leadfoot  



Joined: 11 Dec 2002
Posts: 2222
Location: gOLD cOAST Australia

PostPosted: Mon May 09, 2005 12:35 pm    Post subject: Reply with quote

I was running on a half map as maximum boost had not be determined due to the supercharger not being installed at the first dyno.
What this meant is that the lower half of the map was quite "chunky" as I could not allocate the unused load bands.
So now the object of tuning I required was for smoother running in N/A or off boost driving.
After calculating the MAP max pressure I limited the load bands at 8PSI and used the extras for the lower range of figures.
Seeing as maximum boost was now calculated the advance was increased until it was shown to be reaching maximum power. There were no signs of detonation on the dyno and it was also road tuned before and after the dyno session.
As for detonation detection equipment, well ??, I can't add anything to that. The guys tuning it are pretty cluey and if there were problems I would have found out when it was on the dyno. They probably have an ear for detecting that now, or use a stethoscope.
Inlet temperatures with the addition of the intercooler have actually dropped by ten degrees. I'll have to wait until summer to find out how the ambient temperature really affects the inlet temps. But that's months away now. I have to sort out this drivetube bearing issue and then add my oil cooler. Which I think will make a big underbody temp difference, well at least it should make my oil last a bit longer.
Leadfoot
Back to top
View user's profile Send private message Send e-mail
endwrench  



Joined: 07 Dec 2002
Posts: 1629
Location: Victor, Montana

PostPosted: Mon May 09, 2005 2:03 pm    Post subject: Reply with quote

Your just full of good news! I love the fact you have not seen any obvious detonation signs running the timing you do. I am thinking more and more of going a rout simular to yours and try to build a lower boost setup with my higher compression. Atleast I can try it out before changing out the head and pistons plus building another intake manifold. Time is precious!

Todd
Back to top
View user's profile Send private message Send e-mail
leadfoot  



Joined: 11 Dec 2002
Posts: 2222
Location: gOLD cOAST Australia

PostPosted: Tue May 10, 2005 2:08 pm    Post subject: Reply with quote

I've heard of people running 10:1 compression setups which blowers, but mainly on modern engines. I figured trial and error was the only way I could go with this setup. No one else has run a charger on an N/A, as far as I'm aware they have all been turbo engines.
As I have said to you before, you can limit your boost a number of ways and incrimentally bring it up. If at a later date you decide you want more power then remove this limiting device and replace the pistons. The good thing is you'll allready have the framework set down in place.
You can also get a grind done to reduce static compression a little if it starts getting close, or sell your block and use a turbo block.
I look forward to seeing your setup in the future.
Leadfoot
Back to top
View user's profile Send private message Send e-mail
Lizard  



Joined: 03 Nov 2002
Posts: 9364
Location: Abbotsford BC. Canada

PostPosted: Tue May 10, 2005 3:06 pm    Post subject: Reply with quote

there are a few 928 owners who have run 12PSI on a 10:1 S4 engine with no issues, but most stick with about 5-7 PSI
_________________
3 928s,
Back to top
View user's profile Send private message Send e-mail
leadfoot  



Joined: 11 Dec 2002
Posts: 2222
Location: gOLD cOAST Australia

PostPosted: Tue May 10, 2005 7:17 pm    Post subject: Reply with quote

Those would be frigging fast... I know what a difference mine has made with 3psi at the manifold. I get goosebumps everytime I think of what the final result will be with 7 to 8 at the manifold.
When are you sticking the M90 and bug catcher on??
Leadfoot
Back to top
View user's profile Send private message Send e-mail
endwrench  



Joined: 07 Dec 2002
Posts: 1629
Location: Victor, Montana

PostPosted: Wed May 11, 2005 12:23 am    Post subject: Reply with quote

Yes, I have heard of others using high compression motors and boost too but wasn't too sure about the NA combustion chamber setup. So far your indications are good. Some engines will hardley run with low compression and no boost. I have an artical on a V6 MR2 conversion running 9.5 compression with both a supercharger and turbo!

I will definitly be running some style of boost control if I go this route. Your examples make perfect sense to me now.

Later, (if there is a later) I plan to build another engine using the VW forged Mahle pistons and 931 head along with more boost.

Todd
_________________
'79 924NA. Rebuilt 9.5:1, MSDS header, Mega Squirt Injection, MJLJ-EDIS Ignition, 1.6L Whipple Charger and Intercooler, 10lbs Boost, 944 Trans, Custom HD Clutch.
"simsport" said....superchargers are better than turbos its official!....
Back to top
View user's profile Send private message Send e-mail
morghen  



Joined: 21 Jan 2005
Posts: 8155
Location: Romania

PostPosted: Tue Jul 12, 2005 6:31 am    Post subject: Reply with quote

sorry to ask withount reading what others have asked...what pistons are you using ?
_________________
Ruby-sh 924
Back to top
View user's profile Send private message Visit poster's website Yahoo Messenger MSN Messenger
endwrench  



Joined: 07 Dec 2002
Posts: 1629
Location: Victor, Montana

PostPosted: Wed Jul 13, 2005 2:21 am    Post subject: Reply with quote

He's using stock Euro 9.3 NA pistons.

Todd
Back to top
View user's profile Send private message Send e-mail
leadfoot  



Joined: 11 Dec 2002
Posts: 2222
Location: gOLD cOAST Australia

PostPosted: Sat Jul 22, 2006 5:40 pm    Post subject: supercarger conversion update notes 22/7/06 Reply with quote



Last week I returned "little wheezer" as it's know going to be known to the dyno in order to confirm running air/fuel ratios...
needles to say that I wasn't very impressed, not only were the ratios way into the lean side of running for a forced induction engine but the figures were also less than impressive, measuring less than when I had the last dyno session at a whopping 82 RWHP not quite what I expected....
So not having enough time at the shop I had the air/fuel ratios made a little better and vowed to return next weekend...

So after spending a few hours on the dyno today there's good and bad news...

Firstly the good news...
After sorting out the fuel maps power started to make a turn for the better, each run netted a few more ponies and as the air/fuel ratios started to head toward 12.5 (some from 14.5 I might add) I started to see the results of coming back...
power was climbing from 80 through 90 and rest somewher around 94 RWHP

Enter ignition timing...
Working with the better fuel mapp ignition advance was added closesly monitoring for detonation. Quite suprised at just how much advance the little sucker was responding to the dyno operator wound it up a couple of times to increase power almost instanly to 112 RWHP...

30 RWHP in two hours, I was liking how the number were coming up... although not quite convinced with that being the last straw here comes the bad news... I had been told by a couple of people that my intake manifold for the blower might be choking off performance, so let's take off the air filter and bypass valve to let in as much air as possible and do one final run...
Well my figures jumped another 14 RWHP instantly and improvements from 3000 RPM and up were clearly visible, with 1 more psi regisreing on the dyno too, so I have a job in making a new manifold.
So quite happy with a total of 126 RWHP and with a dyno plot that looks like a different car I'll leave this one for a while Until I get the new manifold built... Needles to say I think there's at least another 10 RWHP probably more very obtainable in the current setup...
There is still a dip in response from 4500 up where the added airflow caused the load to move up a cell in the map and the mixtures went to the side of very rich at 11.5, but this can wait a while...
all in all starting to see the modifications pay off... the dyno operater was thinking around 40 HP in drivetrain loss, even if you put this at 20% it's around 150 BHP, I was thinking roughly 165BHP... I let ya know when little wheezer makes it there...
Leadfoot
_________________
1981 ROW 924 Turbo -
carbon fiber GT mish mash
LS1 conversion in progress...
Back to top
View user's profile Send private message Send e-mail
Display posts from previous:   
Post new topic   Reply to topic    924Board.org Forum Index -> Performance Upgrades All times are GMT + 10 Hours
Goto page Previous  1, 2, 3  Next
Page 2 of 3

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group