Hey all,
Sorry for the lack of updates, season is coming to a close here in upstate NY and I have been crazy busy
As fall sets in and leaves begin to descend the problems start to come to the surface, This post has had a long time coming and is a collection of issues and obstacles i've compiled over the past couple months with the new motor, Im looking for outside advice and opinions on where to move next and how to tackle different issues. I also hope that this could help someone else down the road struggling with similar circumstances. Ive put over a thousand miles on the new build and I'm afraid I've already toasted the snail, along with some other pesky bugs!
I got the car running and driving in the beginning of August and have been in it every chance I can get, I even drove it to a local drag strip, made some passes and made it home, all on a 85+ degree day! I'm beyond thrilled the car is still holding up because it's my first ever project of this caliber; really considering going into a mechanical field because I loved every second of building this monstrosity. (recently picked up a small eaton m62 for dirt cheap, im going to be playing with it on my cammed subaru this winter
)
We'll start with the turbo problems I'm having: I scored a used garrett turbo off a Buick grand national with just over 40k, with just about zero shaft play and great condition. Swapped out the huge exhaust housing for a tiny .36a/r to help the 1776cc engine spool up. I had some exhaust leaks and wastegate problems and thought that's why it wasn't building boost right but even after it was all sorted and wastegate completely sealed off it won't make pressure until approximately ~3k and builds up to redline climbing slowly the whole way only to 12psi. There's hardly any turbo noise except for it cramming air in at full boost. Don't get me wrong the car is really fun to drive and pulls like a bastard in high rpm but I want to spool really low and not have to rev the thing out, the main goal is for the turbo to make boost and hold, not just climb linearly up. I think part of the issue is the header design as well as the outdated turbo technology. (Specs on the snail are Compressor: .63 A/R 50 trim Turbine: .36A/R 70 trim)
Those are the performance issues on t setup but I recently checked the turbo and it has TONs of play and I'm pretty upset, it doesn't contact the housings yet or smoke really at all but it certainly is not right. The motor has never been run hot but I have had an issue with it running too cold, in fact the oil has only reached operating temp (~200°) once and that was waiting in a line for a car show for an hour and a half. It needs a thermostat before the oil cooler but I've just been too busy driving it.
Could cold oil ruin a turbo? Another thing I noticed is at real low idle the turbo hardly spins, sometimes completely stationary, which I know cant be good for it, im guessing this is associated with my low end stumbles also.. but i believe I've narrowed it down to a lean idle circuit in the Dellorto. More on this below
I'd like to keep using a t3 set up and use the existing exhaust housing (.36), maybe replace the cartridge, wheels and compressor housing with newer components, can ball bearing be used a draw through? One of the main reasons I got this Garrett, other than it being from a friend and on the cheap, was because I read carbon seals are necessary on a draw through.
I
f thats all too complicated, what would be a good turbo to replace it with? I thought this current set up would work well, I talked to a couple turbo shops and they agreed, but didn't want to make assumptions until they saw the turbo themselves. I'll need to make a decision if i want to rebuild this turbo (generic t3 carbon seal journal kit) and build the new header
first{(possibly run into same turbo issue)
or jump straight to getting a better, more appropriate turbo for the motor and do the header at the same time. (never know if previous turbo was issue, spend more money unnecessarily??)
I want to take this thing to higher boost levels and spray methanol eventually because i think its capable to run 11s and would be one hell of a ride
but i also
eventually want to put this motor in a ghia/bug, or a fast back
I think that day is far off in the future, and it will stay a killer street buggy for awhile, but the old shells keep getting more expensive so i want to jump now, looking for something with original paint/ or good patina.. oh how i can dream
A header redesign is in order for this winter regardless because the current 4-1 is probably not carrying enough velocity to make pressure for low spool up. The front two cylinders (1 & 3) lose over 100 degrees from the journey over the heads, and thats with a full exhaust wrap! Its a cobbled old baja header and a hooker header 4-1 merge collector that takes 4(four) 1.5" tubes and dumps it into a big 3"-3.25" chamber (has to be a big drop in pressure until in high rpm) before it flows into the turbo, it also has a single external 44(?)mm wastegate, maybe a tial knockoff
, I was thinking it would need a lot of bypass with the tiny exhaust housing, but only hit max ~12psi at redline and is currently sealed off completely...
For the new header design I'm planning to do a 2-1 on each side, so cylinders 1 & 2 merge into one outlet and 3 & 4 merge into their own, then have those two meet into one at the t3 flange. Still plan on sticking to 1.5" runners to avoid cooking valves and high back pressure but still maintain exhaust velocity, once they merge i think ill bump it up to 1.75 so still have room to flow in high revs. Going to use quality flanges and utilize all stainless piping, also take advantage of using flex sections or v-band segments for flexing under load/ ease of assembly/disassembly.
Another pain in my butt in the buggy, besides the plastic seat and solid motor mounts
, is getting the fueling happy during transitioning. The car has never had an issue idling and is no harder to start than any other hot rods, it also is extremely happy in WOT and cruising speeds. I have been keeping an eye glued on the Air Fuel Ratio ever since ive had it out on the road and some numbers i was shocked at with my first guess of jets in the Dellorto 40 DHLA (n). When i first started the turbo build i jetted for a 1600 because that was the original plan with the old case. I used the recommended emulsion tubes and followed the jetting outline in
TURBOMANIA for the smaller engines: (168) main jets, (.65) accelerator pump jets, and (.68) idle jets. Started the motor with (3 1/2) turns out on the idle adjusters and it was idling around 15.0 but had a unbearable stumble when you pressed in the pedal quickly, you had to ease it very slowly to keep it happy, It would buck and pop and jump super lean. Once it was at 3k it was fine and behaved normally, for the most part; pretty good response and AFRs if you pedaled it gently. It would lean out as you accelerated with the pedal pushed aggressively until it started to build boost and it it would pull fuel in and hold a perfect 14.5 all throughout boost and redline, that was on waste gate spring pressure of 5lbs.
Ran buggy like this for awhile with some tweaking and it was bearable, but still didn't have any throttle response (besides responding in backfires and bucking) or power at all in low rpms and had to downshift to accelerate if i was under 3k. Never had a lean issue at WOT so i figured it was accelerator jets and put in another order with eurocarb. The second jets i got were (1.72) main jets and (.70) accelerator jets. I knew I would need more fuel for higher boost, so i shimmed the wastegate and put the bigger 1.72s in and it holds around -14.7 all the way up to redline (wastegate is
nowblocked off and still holds decent AFRs up to 12psi).
This helped a decent amount with the low stumbles but it will still do it if you jab the pedal at any rpm, the problem still persisted and I stooped to a new low point in the project; I drilled out the old authentic Dellorto accelerator jet with an American bit
at least 3 times the original size! The car is so much more drivable and behaves properly under moderate acceleration but still leans out under
hard acceleration, until boost kicks in!:evil: I believe with the proper idle jets I can size the pump jets back down and all will be right in the fuel world. I have yet to up the idle jets, but that will definitley be the next step,
TURBOMANIA recommends (.70), especially if you're having leaning out from transition to main circuit. But i think that might be the culprit and if that
finally is not the source of the issue than I will downsize the venturis from: 32 to: 28, always have to have a plan of attack for bettering the buggy. Overall I would like all my numbers to be a little richer, around 12.0 or 13.0 at peak boost to be safe(and throw some fire?)
Some of this makes me wish i went fuel injected but this thing is so simple and fun, ill save the computers for water cooled contraptions in my future!
A final thing that could be causing headaches is the OG bosch distributor! The first couple hours of initial startup i was having spark issues. (using a MSD 6btm and a magnetic pickup) Sometimes I would get like one spark on each plug for one revolution of the crank right when i turned the key, then nothing. And then i couldn't get it to put a spark down at all I messed with it for awhile, switched it from the green/violet to the white pickup on the MSD and still no luck; probably burned out? Changed the caps and rotors and went through all trouble shooting on the MSD without finding any problems there. My buddy found out the hard way that the coil was also getting power
so the issue was with the magnetic pickup distributor, plopped the original gangster bosch(?) point style distributor in and used the white lead off the MSD, I don't know much about it at all, haven't touched it after the car was running with it. Set the static timing to 10-11 BTDC and full advance is around 35 degrees. Pulling around 1.5 degrees per pound of boost usually on 91, used octane boosters and pulled around .8 and felt like i was going to take off. Definitley want to play with timing more, found that pulling more helped the motor build boost faster but runs out of steam very quickly.
Congratulations if you've stayed and read all of this post, i know its a lot of mad rambling but ive been meaning to update this for a long time and had all sorts of snippets of things to add. Overall i'm thrilled with the buggy and cant wait to unlock even more of its potential!
*** as a last side thought, ive had depth wobble quite bad recently at 25-35 mph and believe i have traced it down to flattened tie rod bushings on the dog bone off the steering box. anyone have tips to finding out which style you have? I did front calipers and lines recently but plan to do a disc swap up front this winter. What else are some good things to do a link-pin buggy for street driving? Feels true and steady at highway speeds but hunts around the lane, front wheels have a lot of camber.
