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Should I go from gas to turbo diesel for autocross?
by
diygti
on 29 Dec, 2007 23:22
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I've been considering a turbo diesel for my 1975 rabbit that I use for FSP class autocross. After seeing FSPGTD's car on the internet I was even more inspired.
My car was very nicely set up with a 1.8jh gas engine before it developed a rod knock:
http://www.youtube.com/watch?v=zpbCqmAKag4Am I right to believe that I could get more power and torque out of a 1.6td than my 1.8jh? (It had 90 hp new) I read on another forum that fspGTD was making 150 foot pounds of torque and 100 horsepower. If I had that much power my car would be unbeatable. The cons are that I would lose the sweet sound my gas engine now makes, and the only FSP legal A1 turbo diesel I can find is at a junkyard in LA for $1000, which seems like a rediculous price.
Comments and advice please!
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#1
by
jtanguay
on 29 Dec, 2007 23:40
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what modifications are you entitled to on the engine? i'd say $1000 isn't too bad depending on the shape. If its a 1.5 i wouldn't get it, although they do rev slightly better than the 1.6.
your best bet is to talk the junkyard guys down. ask to see it run. if it doesn't, then don't pay $1000. if it runs good then $1000 isn't so bad. if it starts rough, you can talk them down a bit. the car is only going to depreciate in the junkyard :wink:
IMO diesels make some pretty kick ass sound when they're at 4k rpm. there's just so much banging going on under the hood that its like a diesel orchestra! :lol:
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#2
by
diygti
on 29 Dec, 2007 23:48
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According to F street prepared rules you cannot change the turbo or increase boost, and the engine must remain stock internally. Allowed modifications would include an intercooler, injector and injector pump changes, and a bigger exhaust after the turbo.
$1,000 for one of these engines sure is steep. Its a shame VW didn't make more of them.
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#3
by
Patrick
on 30 Dec, 2007 04:32
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A few things: Volkswagen made LOADS of them, they just didn't sell that well where you are.I've got 6 or 7 in various states of repair/disrepair. There's others on the forum that could set you up with a good onefor reasonable money if you can get around the transportation costs.
Limiting the boost is going to be your big problem. There's only so much power to be gained without upping the air to match the extra fuel you're going to dump into that thing. Is there a class you can run with extra boost allowed? Guys are talking 200 whp with the right mods, but that means 2 or 3 times stock boost levels..........
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#4
by
Pat Dolan
on 30 Dec, 2007 05:59
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By our rules, that would be an engine swap (since threre were no turbodiesel A1 bunnies) and put you into (C or D?) Mod, where you would be up against pure race cars.
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#5
by
diygti
on 30 Dec, 2007 10:51
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I used to think this wasn't possible either under the rules, but there most definitely were some A1 bunnies from the factory with turbo diesels around 1984. A rabbit with a 1.6td swap that regularly autocrosses in Portland placed third at the SCCA nationals in Topeka recently in FSP (FSPGTD on this forum). These factory machines are quite rare, but here's one example:
click here
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#6
by
TedV
on 30 Dec, 2007 13:16
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I’ll let you know how an FSP TD compares this spring. Ive driven a few autocross cars. Jake wasn’t 3rd, he ended up 10th at the 2007 Solo Nationals. Last trophy spot out of 34 competitors. There were 3 gas VW’s in the trophies at 7, 8, 9th. I get to run with Jinx here in the south, he was 2nd at Nationals. Ive wanted to build a performance diesel for a while. Think I’ve pissed a few people off over on TDIclub saying an IDI Mk1 will make a better autoX car than a heavy TDI. I was bummed about not being able to road race, so TD build is therapy. I have a Formula Ford to fall back on if the TD isn’t fun or competitive. Can’t see it not being fun or competitive tho, and hope to sell the FF.
Read the 2007 rules (2008 are not out yet) then read and read again. My 2007 book is at the machine shop with my block. No bumpers put you in prepared
All Mk1 FSP VW’s are on the same line, so you can update- backdate almost anything that fits without modification. The engine block you need must have a CY stamping. It was in an 83 or 84 Rabbit or Jetta. The 85 mechanical MF is the same but is protestable because MF was never in a MK1 chassis. You can not modify the turbo, turbo wastegate or the pop off valve. But boost increases by other legal mechanical or electronic means is legal. Fuel injection, intake manifold, exhaust manifold mods are open. Read that section again and be creative. You will have more torque but I’m not sure on the HP with FSP legal tune. Top JH motors are putting out over 120 hp. at the crank. I ran my 1.8 in a 79 Scirocco at Charlotte Mtr Speedway driver school years ago and was passing Mazda RX-7’s in the banking. Gearing the TD is a question since it does not rev as high as a gas, I have every Mk1 ratio available to me except the 4spd with 4.17 final. I’ll beter know what trans to run after I dyno my motor.
Building a TD is not cheap if you want to stay legal for FSP esp with 25 year old parts you are going to abuse. I will have more in the motor than the entire “Grassroots Mtr Sports $2001 challenge” SM turbo Scirocco build. But you get 40mpg to save money down the road.
Just do what you think will be fun, that’s what its about. Turbo's sound cool too :wink:
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#7
by
diygti
on 30 Dec, 2007 13:34
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Thanks for that post. FSPGTD was using a rabbit gti close ratio transmission I believe, and driving it around most courses in third gear, sometimes downshifting to second. My car already has that tranny so I would be set for a nice start in that regard.
What I would like to is megasquirt when it is developed to run diesels. Im always baffled as to why something like that hasn't happened yet.
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#8
by
Patrick
on 30 Dec, 2007 14:57
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You can not modify the turbo, turbo wastegate or the pop off valve. But boost increases by other legal mechanical or electronic means is legal. Fuel injection, intake manifold, exhaust manifold mods are open. Read that section again and be creative.
Just do what you think will be fun, that’s what its about. Turbo's sound cool too :wink:
I'm thinking a mk3 2 door golf/AAZ fits the class and has a lot of room to crank, no blowoff valve, an air bleed on the boost line, and tons of fuel...........
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#9
by
jtanguay
on 30 Dec, 2007 18:04
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You can not modify the turbo, turbo wastegate or the pop off valve. But boost increases by other legal mechanical or electronic means is legal. Fuel injection, intake manifold, exhaust manifold mods are open.
so basically passenger performance manifolds, huuuuuuge intercooler, boost controller, the pop off valve can be adjusted to not open just by tightening the screw inward (does this count as a 'modifying'?) and a Giles pump with some GM 6.5 nozzles on it. :lol: yea the price of that car is rising steadily, but i'd imagine it to have around 140hp and 200 ft/lbs of torque... easily! shoot for 160 hp and then everything gets iffy....
lol what if your wastegate was 'stuck'??? :twisted:
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#10
by
TedV
on 30 Dec, 2007 21:40
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I don’t know of any protests on turbo waste gates and pop off valves in street prep off the top of my head that would set a precedent. The general thinking from what I understand is the waste gate and pop off valve must function at the stock pressure setting when and if they ever see that pressure. :wink: :twisted: So when removed from the car and put on a pressure tester in the tech shed, they should open in the factory set range. Parts that are “stuck” or missing have been found to be non-compliant and illegal in the past. They caved in to the boost allowance because on computer controlled cars, there can be several maps controlling the boost, no way to police that. If you don’t finish in the trophies, most people don’t care how incorrect your car is, but if you do, you better be sure all is correct. Besides, what fun is it to win if you cheat? Not sure if the Eco intake and the pop off valve in the glove box would be considered legal, but I have wondered about that. All Mk1 TD had the pop off valve, so it needs to be there someplace.
I have the close ratio 5spd but would like to loose the weight if a 4spd would work. You can get a Mk1 in the 1700 to 1800 lbs range. My SM Scirocco had to weigh 1900 lbs per class rules, hit scales at 1910 to 1925 depending on fuel load. My 98 TDI Jetta weighs 2900 lbs. 75 Rabbit is light, very good. Next year starts the 20 lbs min. seat rule using factory mount holes in street prep. Do you have the aluminum bumpers with non-telescoping mounts yet?
I ran mega squirt on the SM Scirocco both 16V and ABA2.0 16V turbo. I doubt MS will have a diesel version because of the pressures needed by a diesel injector are so high
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#11
by
jtanguay
on 08 Jan, 2008 01:38
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so you mean you can't just thread that thing in to make it pop at a different psi? i'm sure not all blow off valves open at the same pressure... :wink:
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#12
by
TedV
on 08 Jan, 2008 09:32
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If you run SCCA Street Mod you can modify it, or leave it off, but in F Street Prepared it has to be on the car and open when there is a difference of 12 psi (factory range going from memory) between the bottom and top. it's ok to modify the intakein FSP, just not the valve itself. so wonder where it will vent to on my car? :wink: :twisted:
rules can be a pain :roll: but need to be prepared in case someone desides to protest and have to tear apart the car. I may end up slow, but don't plan on being slow. :lol:
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#13
by
jtanguay
on 08 Jan, 2008 10:36
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so the rules don't specify where it has to vent to? hmmmm maybe it can vent itself back to itself? :lol:
if people got beat by a diesel they'd be pretty pissed.. and probably want to start some crap like what happened to the audi R10 :lol:
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#14
by
jimfoo
on 08 Jan, 2008 10:52
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If you run SCCA Street Mod you can modify it, or leave it off, but in F Street Prepared it has to be on the car and open when there is a difference of 12 psi (factory range going from memory) between the bottom and top. it's ok to modify the intakein FSP, just not the valve itself. so wonder where it will vent to on my car? :wink: :twisted:
And has to be open how far? :twisted: Maybe just enough to let a little air out but still be able to make more boost?