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Better with Boost: My Turbo Spider Journey

46K views 267 replies 30 participants last post by  nealric 
#1 · (Edited)
EDIT: Working on fixing broken photobucket links.

I've been asked about a build thread for my spider a few times, and realized that the original was languishing in obscurity in the engine conversion thread, as it was originally an ITB build. As explained on the thread, the initial turbo build was fantastic engineering beyond my personal capabilities.

Where the build left off under the hood:



http://www.alfabb.com/bb/forums/engine-conversions/165308-itbs-megasquirt.html

Since I am continuing the project, it's time to post a new thread. As it sits, it's running 5psi of boost (will likely bump to 7-8 sooner rather than later) and probably around 140-50whp (hope to get it on a dyno soon!). I've run it in a few autocrosses and found to be a total blast with the upgraded suspension and brakes. Unfortunately, it would take a pretty wild build to make it competitive in autocross (SSM would be its class with the turbo).

I expect this to be an ongoing project over many years, but my ultimate vision is a spider with around 250whp, T5 transmssion (or if I hit the lottery, the Alfaholics sequential transmission), watts linkage in the rear, upgraded diff, a new paint job with a color change, and perhaps some fender flares for bigger rubber.

But, before any of that, I wanted to get this thing driveable a real track so it's capabilities can be properly exploited. I'm planning on having a roll bar similar to msiert's fabricated in January, and just installed a pair of race seats to get the roll bar fitment squared away. Next will come 6 point harnesses and probably a new steering wheel (the old one hit my legs even with the stock seats).

 

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#68 ·
I've often wondered if it is possible to make the head studs go right threw the bottom of the block and the create a 4 bolt main bearing setup.

There would have to be a step or shoulder on the stud somewhere, and maybe not enough room, but if possible a stronger method than relying on aluminum threads
Pete
 
#69 ·
Interesting idea. I will hold on to this block and may experiment with it. One idea I had for repair is to use an aluminum brazing rod to fill the hole and a heated stud, then back out the stud before the material is fully cooled.

May try it for a backup motor, but doesn’t make sense to use a wonky block with expensive liners, rods, and pistons.
 
#73 ·
I think the way to do it on Nord would be separate girdle that keys into the main caps. Almost like a really thick windage tray that also accepts the head studs. You'd probably also want billet main caps that are machined to accept the girdle. But it seems to me that you can already make more power than the chassis can really handle without going that far.
 
#74 ·
Got some good cleaning done yesterday. I did the last block with lots of scrubbing. This time around, I used a power washer and aluminum brightner. Easily 1/4 the effort to get the block clean. Still prepping the mating surfaces with the old razor blade method, so a bit longer. Hopefully should have the motor ready to begin assembly by Friday.

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I know I could just take it to a machine shop and have it cleaned, but I’m over machine shops at this point.
 
#75 ·
Well it's been a very frustrating day. The motor was supposed to start coming together, but I'm utterly stuck on the crank. Everything should be the same- same caps, same bearings, same crank- except the block of course. Clearances are measuring at .001 as before. But once the main caps are fully torqued, I cannot turn the crank over even with a breaker bar. At 25ft lbs, it turns though it is tight, 36 and it's a total nope. Tried both my torque wrenches for good measure. Tried regular motor oil instead of assembly oil too.

I've taken the whole thing apart 3 times now (not including the clearance check) and still can't figure out what's going on. Can't figure out whether I'm doing something boneheaded, or some issue with the new block.
 
#80 ·
My original block was toast and the new one didn’t come with main caps. So it might be that the other main caps were a better match.

Part of my problem is the limitations of plastiguage for checking tolerances. You only get the tolerance at one point, and there is no resolution below .001in. The old main caps were showing .001, but they very well have been below that in spots.
 
#82 ·
Thanks. That’s a new one on me, but it makes sense.

It explains my trouble with the initial assembly. We (my friend who supplied the donor and I) are fairly certain that the caps I used today are the correct ones for the block.
 
#84 ·
New motor almost ready to go back in. Just odds and ends now (although odds and ends have a way of adding up to a lot of work!). Hoping to have it in the car this month.

I took most of last weekend installing a ductless mini split air conditioner in the garage, which delayed things a bit. All I can say it’s a game changer for working over the summer in Houston.

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#86 · (Edited)
Right now, I’m running the Garrett T25 ar .80 that came with the car and that I ran earlier. Never got it on the dyno but I’m guessing I was in the 150-170whp range at 8psi. Initial HP goals are 200-250whp at 15psi. I’m interested in eventually upgrading to one of the new g25 550 and going for 300whp. Most likely I would only turn it up to high boost occasionally and run more like 10-12 outside of autocross and time trials.

New motor has slightly lower compression (8.5:1), but performance cams and other head work. Will be interesting to see how the better flowing head will impact spool and power at similar boost levels.
 
#89 · (Edited)
It should have the potential for a lot more than that from a motor standpoint. More a question of keeping the drivetrain together and finding traction. This version will hit the dyno, so we shall see!

Also, I was corrected by the original owner: the turbo is actually a GT28RS. It should be good for more like 300WHP.
 
#93 · (Edited)
Brief update before I head out for vacation. There was a bit more troubleshooting than I had initially expected after getting the car running. Throttle position sensor wasn’t reading, which was traced back to a wire that had broken from vibration and potentially handling during the uninstall. All sensors are now working l, but the car won’t idle. Dies below 1,200RPM. It’s almost certainly a tuning or electrical issue. The car was running great on the stock motor, but the tune may be too far off with the more aggressive cam and changed compression ratio. Can’t really drive it until it idles. Hopefully I can get that sorted soon. Car needs to go back to the paint shop for touch up promised by the original painter.

To do list (in the immediate). Need to fabricate a new bracket for the coil (you’ll see it’s just zip tied for now). The old one made out of aluminum crumbled from vibration. New one will be steel. Interior buttons will need a mount fabricated as I’ve decided not to do a center console.

Last item is the floor. Purchased some nice rally style drivers footrest and passenger footrest. Will be installed with nutserts and threaded rod for leveling.

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#95 ·
It makes more sense when you see the brackets and how they were attached. The brackets were u-shaped units that replaced the washers for the head studs. The relatively heavy ignition coil sat on top. Normal engine vibration would have caused small amounts of flex in the bracket as it sat on top. Aluminum continually weakens as it flexes, so after many many cycles it cracked near the head nuts. Anyhow, the old motor ran smooth and there was no undue vibration.

This time around, I’m using stiffer mounts (the harder rubber ones Spruell sells and the aluminum trans mount). So far I’m actually pleasantly surprised that vibration isn’t too bad.
 
#96 ·
Have it idling now, though more work likely needed to get it perfect. Needed more timing and less fuel, plus a tweak to idle adjustment on the throttle body itself.

Happy that it was a simple tuning matter. It does make me realize that the new cam and lower compression ratio is going to necessitate a lot of tuning. Want to get it running and driving well before it hits the dyno. Plus will need some more motor break in time.
 
#97 ·
Had a chance between packing and cleaning up the house to taker her out for her first drive in 2 years! Just around the block so far. There’s a lot of tuning left to do, but happy milestone.

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Too early for real driving impressions, but the alfaholics clutch feels like stock. The lightened flywheel certainly caused it to rev more freely.
 
#98 ·
Getting back at finishing things up. Got the driver’s heel plate installed with nutserts and am working on tuning. Idle still needs work.

Took it out for a second drive yesterday and the car died on me with an approaching thunderstorm. Car stalled and then lost all electrical. Ended up pushing the car home (fortunately only a block) and got it back into the garage just before the skies opened up. What was it? Turned out nothing but a dirty battery ground.

Question for the electrical gurus: how the heck does the car go from having enough power to start multiple times to completely dead in seconds from a battery ground? Nothing was loose, but when I cleaned the ground connection on the chassis with some sandpaper, everything came back right away. Other than dielectric grease anything to help keep that from happening again?
 
#101 ·
nice engine install.. an idea for you, maybe? those seats sit kinda high i did the math off the photos, your eye level will be in the the upper 1/3 of windsheild,, if you go to my maita seat install, i side mounted the seats, and at 6 foot tall, i look out of the lower 1/3 of the windsheild, and very nice to sit in..
 
#102 · (Edited)
I think that’s a bit of an illusion from the height of the seat back. Not really room to go lower without “bottoming out” the seats which basically work like a hammock. They are actually side mounted off the bracket. Keep in mind that these Sparcos are very deep buckets, so the front of the seat is higher than where you actually sit.
 
#103 ·
Small update. Still working on odds and ends before it’s ready for the open road. Biggest issue is charging/battery. I think it may just be a bad battery (it is an old one). Although it starts the car straight off the battery tender, it was down to 11v (and not turning over the starter) after about 10 minutes of driving. Alternator was putting out good voltage and all connections are confirmed clean and tight.

Added the rally style heel rest and a dead pedal. It is secured by nutserts and a locknut that allows height adjustment.

Besides the battery issue and a dire need of an alignment, it was driving well. Still more tuning to do. I spent about 2 hours working on the idle. Much better, but not perfect. The megasquirt is both good and bad in that the possibilities for adjusting fuel and timing are nearly infinite. You can drive yourself crazy trying to get things perfect.

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#104 ·
Bonus photo of the engine bay as it sits. The ignition coil is temporarily zip tied in place. I have ordered metal stock to make the proper bracket. I will also need a bracket to hold the turbo coolant hose that goes over the valve cover.

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