wanting to know what the 10.1 comp 110hp engine came in and what years,were they hyd or solid lifter,and whether the head/intake flow better than the 8.5 comp engines and if my existing 90hp would be a direct swap,just getting in to the vw upgrades?
8v engine component interchange?
85silverbullet
1 - 12 of 12 Posts
Joined
·
16 Posts
wanting to know what the 10.1 comp 110hp engine came in and what years,were they hyd or solid lifter,and whether the head/intake flow better than the 8.5 comp engines and if my existing 90hp would be a direct swap,just getting in to the vw upgrades?
Re: 8v engine component interchange? (85silverbullet)
The European-spec Mk1 GTi had a 110 hp, 1.6 l engine. Don't recall the compression but it was probably around 10 or 10.5. I honestly don't know what made it so much hotter than the NA-spec motors besides the compression, possibly it ran a G-grind camshaft and the methods of certifying hp may have been a little different in Europe too.
NA-spec GTI's (and your 'Rocco) had the JH motor, 1.8 l, "big valves" (40x33) and 8.5:1 compression. I BELIEVE that swapping in the pistons from a Mk2 GTI motor (don't remember the code) or a Mk2 Digifant motor will provide 10 or 10.5 compression right off the bat, since the JH pistons are dished to lower compression.
All Mk1 motors were solid lifter
In the Mk2's, there was a 100 or 102 hp CIS-E engine that came in GTI's and Carats. There was then a 100 or 105 hp motor in all Digifant Mk2's, the difference being the dual downpipe/manifold.
All Mk2's and 3's are hydro lifter
Moral of the story....a head swap will do nothing for you, but a piston swap will. That plus a better cam (aftermarket), head porting and an OEM 4-2 exhaust manifold and downpipe (has to be from a Mk1 I believe) will open your engine up. Keep the Mk1 intake manifold, keep your fuel injection as-is and maybe add one or two shims to bump the fuel pressure up if you add the other mods. If you go to higher compression you may want to add a knock box from a CIS-E engine (mk2 8v GTI would be the proper donor I believe), or at the very least run premium gas
Modified by Mr Black at 5:05 PM 12-23-2006
Modified by Mr Black at 5:06 PM 12-23-2006
The European-spec Mk1 GTi had a 110 hp, 1.6 l engine. Don't recall the compression but it was probably around 10 or 10.5. I honestly don't know what made it so much hotter than the NA-spec motors besides the compression, possibly it ran a G-grind camshaft and the methods of certifying hp may have been a little different in Europe too.
NA-spec GTI's (and your 'Rocco) had the JH motor, 1.8 l, "big valves" (40x33) and 8.5:1 compression. I BELIEVE that swapping in the pistons from a Mk2 GTI motor (don't remember the code) or a Mk2 Digifant motor will provide 10 or 10.5 compression right off the bat, since the JH pistons are dished to lower compression.
All Mk1 motors were solid lifter
In the Mk2's, there was a 100 or 102 hp CIS-E engine that came in GTI's and Carats. There was then a 100 or 105 hp motor in all Digifant Mk2's, the difference being the dual downpipe/manifold.
All Mk2's and 3's are hydro lifter
Moral of the story....a head swap will do nothing for you, but a piston swap will. That plus a better cam (aftermarket), head porting and an OEM 4-2 exhaust manifold and downpipe (has to be from a Mk1 I believe) will open your engine up. Keep the Mk1 intake manifold, keep your fuel injection as-is and maybe add one or two shims to bump the fuel pressure up if you add the other mods. If you go to higher compression you may want to add a knock box from a CIS-E engine (mk2 8v GTI would be the proper donor I believe), or at the very least run premium gas
Modified by Mr Black at 5:05 PM 12-23-2006
Modified by Mr Black at 5:06 PM 12-23-2006
Joined
·
16 Posts
Re: 8v engine component interchange? (85silverbullet)
so my jh head is a better choice than what comes on the gti 10.1 motors-also wondering if this pacesetter header 1 3/8 pri 2' collector will flow better than the 4-2 manifold's?
so my jh head is a better choice than what comes on the gti 10.1 motors-also wondering if this pacesetter header 1 3/8 pri 2' collector will flow better than the 4-2 manifold's?
Joined
·
462 Posts
Re: 8v engine component interchange? (Mr Black)
hey,
Ive got the same engine as the OP and Im also interested in this idea of bringing the compression ratio up. Do you know which pistons are used to make the compression 10-10.5? is there anywhere to find out? I will try searching after I post. Im guessing any mark 2 that has that compression ratio? because as far as I know the heads have the same sized combustion chambers as the 8.5s right? Would it be possible to just swap the entire bottom end for a newer mark 2 one? instead of taking it apart to get the pistons? But then again if your gonna do that you might as well do a 2L swap right?
This is exactly the mods I plan to do to my car if I decide to keep the stock motor. You can also add a mark 2/ Audi 5000 throttle body since its larger then stock.
| Quote, originally posted by Mr Black » |
NA-spec GTI's (and your 'Rocco) had the JH motor, 1.8 l, "big valves" (40x33) and 8.5:1 compression. I BELIEVE that swapping in the pistons from a Mk2 GTI motor (don't remember the code) or a Mk2 Digifant motor will provide 10 or 10.5 compression right off the bat, since the JH pistons are dished to lower compression. All Mk1 motors were solid lifter In the Mk2's, there was a 100 or 102 hp CIS-E engine that came in GTI's and Carats. There was then a 100 or 105 hp motor in all Digifant Mk2's, the difference being the dual downpipe/manifold. All Mk2's and 3's are hydro lifter |
hey,
Ive got the same engine as the OP and Im also interested in this idea of bringing the compression ratio up. Do you know which pistons are used to make the compression 10-10.5? is there anywhere to find out? I will try searching after I post. Im guessing any mark 2 that has that compression ratio? because as far as I know the heads have the same sized combustion chambers as the 8.5s right? Would it be possible to just swap the entire bottom end for a newer mark 2 one? instead of taking it apart to get the pistons? But then again if your gonna do that you might as well do a 2L swap right?
| Quote, originally posted by Mr Black » |
Moral of the story....a head swap will do nothing for you, but a piston swap will. That plus a better cam (aftermarket), head porting and an OEM 4-2 exhaust manifold and downpipe (has to be from a Mk1 I believe) will open your engine up. Keep the Mk1 intake manifold, keep your fuel injection as-is and maybe add one or two shims to bump the fuel pressure up if you add the other mods. If you go to higher compression you may want to add a knock box from a CIS-E engine (mk2 8v GTI would be the proper donor I believe), or at the very least run premium gas |
This is exactly the mods I plan to do to my car if I decide to keep the stock motor. You can also add a mark 2/ Audi 5000 throttle body since its larger then stock.
Re: 8v engine component interchange? (polskipolak)
Yeah...by rummaging around in here
![Image]()
Try and send an IM to vwpat or ABA Scirocco, these guys know their stuff.
I'm pretty sure that the pistons out of any Mk2 which made over 100 hp will bump the compression. That means GTI's, GLI's (Canadian market GLI that is), Carat's and any Digi motor.
Yes, and yes
Good point, but depends what you have lying around. Also the ABA block requires a bit more fooling around and a few more parts (block off plate, etc).
| Quote, originally posted by polskipolak » |
hey, Ive got the same engine as the OP and Im also interested in this idea of bringing the compression ratio up. Do you know which pistons are used to make the compression 10-10.5? is there anywhere to find out? |
Yeah...by rummaging around in here
I'm pretty sure that the pistons out of any Mk2 which made over 100 hp will bump the compression. That means GTI's, GLI's (Canadian market GLI that is), Carat's and any Digi motor.
| Quote » |
| as far as I know the heads have the same sized combustion chambers as the 8.5s right? Would it be possible to just swap the entire bottom end for a newer mark 2 one? |
Yes, and yes
| Quote » |
| But then again if your gonna do that you might as well do a 2L swap right? |
Good point, but depends what you have lying around. Also the ABA block requires a bit more fooling around and a few more parts (block off plate, etc).
Re: 8v engine component interchange? (85silverbullet)
I think they're all 40x33.....just make sure if you run solid lifters you run the correct cam, and same with hydro lifters. In theory, if you wanna go nuts with a wild cam, solid is better, but otherwise hydro can take up to a 288 deg cam.
Doubt it's that much better, but if you have a header lying around then sure, use it.
| Quote, originally posted by 85silverbullet » |
| so my jh head is a better choice than what comes on the gti 10.1 motors |
I think they're all 40x33.....just make sure if you run solid lifters you run the correct cam, and same with hydro lifters. In theory, if you wanna go nuts with a wild cam, solid is better, but otherwise hydro can take up to a 288 deg cam.
| Quote » |
| -also wondering if this pacesetter header 1 3/8 pri 2' collector will flow better than the 4-2 manifold's? |
Doubt it's that much better, but if you have a header lying around then sure, use it.
Joined
·
462 Posts
Re: 8v engine component interchange? (Mr Black)
I just did some searching. From what I read, you are correct mr black. Any mk2 engine bottom end will fit. RD and HT are the engine codes to look for that have 10:1, there might be more, these are the 2 I found.
Yeah its true that you need extra parts for 2L. Also from the research Ive done..the 3A engine bottom end from an audi would be easier then an ABA bottom end. This is because the 3A is the same size as a 1.8L while the ABA is taller which requires a different exhaust setup. Block off plates are required for both I think, could be wrong though. And also the distributors are different, but again im not sure which ones are interchangeable.
I just did some searching. From what I read, you are correct mr black. Any mk2 engine bottom end will fit. RD and HT are the engine codes to look for that have 10:1, there might be more, these are the 2 I found.
Yeah its true that you need extra parts for 2L. Also from the research Ive done..the 3A engine bottom end from an audi would be easier then an ABA bottom end. This is because the 3A is the same size as a 1.8L while the ABA is taller which requires a different exhaust setup. Block off plates are required for both I think, could be wrong though. And also the distributors are different, but again im not sure which ones are interchangeable.
Joined
·
148 Posts
Re: 8v engine component interchange? (polskipolak)
Guys, Don't even mess with a 1.8L (10:1) block RD or HT. Especially don't mess with a piston swap. I did the RD block swap from a JH. More power, better throttle response...only 6 hp to the ground difference from the G-Tech computer (93 vs 99). This is with a complete Tectonics exhaust (2.25 inch) with TT dual downpipe.
Keep in mind the 90 hp JH had a smaller exhaust, older design intake manifold and conservative fuel and ignition settings. Since the factory hp was 90 vs 102-105 thats 12-15 hp...but when changing to a better exhaust and using the Audi 4000 intake (and larger throttle body) (larger like the golf), advancing the ignition timing (from 6deg. to 10 deg.), and ensuring a good fuel mixture (with air/fuel gage) the difference closes to 6 whp.
The Audi 3a 2.0L (the 10.5:1 compression must use the knock sensor system) has the same highth block so exhaust is same. Keep in mind the 3a cylinder head and intake/injectors are different.
A better swap is the aba even with the 16 mm taller block. I just got done with one (big difference). I had a machine shop fab a 1/2 inch steel exhaust spacer (between the A3 manifold and the TT downpipe), 6 longer exh. manifold studs required (10 x 1.5 mm x 47 mm long vs 40 mm) and an extra gasket. You also need a block breather block-off plate and a distributer spacer from Techtonics (TT). Use the later golf RD distributor (86-89) because the advance springs are stiffer yeilding slower ignition advance..needed for the higher compression not to ping. Will have to use premium gas ,especially in the summer. There is clearance issues with the throttle cable end at the throttle body, bending the upper firewall slightly near the hood seal works. You get 200 cc more, higher compression to 10:1, longer rods (smoother operation), and lighter pistons. Use the old 210 flywheel (lighter) works fine. It would be a good time to replace the rear main seal in the engine and a new clutch disk. Have not got measurements yet, but I would estimate 115 -125hp to ground (easily) with a stock cyl. head (G-cam is installed).
Guys, Don't even mess with a 1.8L (10:1) block RD or HT. Especially don't mess with a piston swap. I did the RD block swap from a JH. More power, better throttle response...only 6 hp to the ground difference from the G-Tech computer (93 vs 99). This is with a complete Tectonics exhaust (2.25 inch) with TT dual downpipe.
Keep in mind the 90 hp JH had a smaller exhaust, older design intake manifold and conservative fuel and ignition settings. Since the factory hp was 90 vs 102-105 thats 12-15 hp...but when changing to a better exhaust and using the Audi 4000 intake (and larger throttle body) (larger like the golf), advancing the ignition timing (from 6deg. to 10 deg.), and ensuring a good fuel mixture (with air/fuel gage) the difference closes to 6 whp.
The Audi 3a 2.0L (the 10.5:1 compression must use the knock sensor system) has the same highth block so exhaust is same. Keep in mind the 3a cylinder head and intake/injectors are different.
A better swap is the aba even with the 16 mm taller block. I just got done with one (big difference). I had a machine shop fab a 1/2 inch steel exhaust spacer (between the A3 manifold and the TT downpipe), 6 longer exh. manifold studs required (10 x 1.5 mm x 47 mm long vs 40 mm) and an extra gasket. You also need a block breather block-off plate and a distributer spacer from Techtonics (TT). Use the later golf RD distributor (86-89) because the advance springs are stiffer yeilding slower ignition advance..needed for the higher compression not to ping. Will have to use premium gas ,especially in the summer. There is clearance issues with the throttle cable end at the throttle body, bending the upper firewall slightly near the hood seal works. You get 200 cc more, higher compression to 10:1, longer rods (smoother operation), and lighter pistons. Use the old 210 flywheel (lighter) works fine. It would be a good time to replace the rear main seal in the engine and a new clutch disk. Have not got measurements yet, but I would estimate 115 -125hp to ground (easily) with a stock cyl. head (G-cam is installed).
Joined
·
462 Posts
Re: 8v engine component interchange? (Ben B (Bengineer))
Thanks man. Its good to hear that someone has tried this and thanks for the info about the worthlessness of this mod
![Image]()
Thanks man. Its good to hear that someone has tried this and thanks for the info about the worthlessness of this mod
Re: 8v engine component interchange? (polskipolak)
Good info.
Another possibility is just to shave the head down far enough that the compression gets where you want it. The piston has the reliefs cut right where the valves are so that should allow more of a shave/bigger cam lift than a flat-top piston would allow.
Anybody know how far you can shave a counterflow head on a JH? Somebody must have calculated this before..........
Good info.
Another possibility is just to shave the head down far enough that the compression gets where you want it. The piston has the reliefs cut right where the valves are so that should allow more of a shave/bigger cam lift than a flat-top piston would allow.
Anybody know how far you can shave a counterflow head on a JH? Somebody must have calculated this before..........
Joined
·
16 Posts
Re: 8v engine component interchange? (Mr Black)
so i guess if i just do a g cam swap,header/exhaust,and i have an audi 5000 t-body/k&n-timing advanced-sounds like i won't be losing noticeable power compared to the aba and this '84 rocco hopefully will get out of it's own way
so i guess if i just do a g cam swap,header/exhaust,and i have an audi 5000 t-body/k&n-timing advanced-sounds like i won't be losing noticeable power compared to the aba and this '84 rocco hopefully will get out of it's own way
Joined
·
148 Posts
Re: 8v engine component interchange? (85silverbullet)
Yes, you are on the right path to enlightenment GRASSHOPPER..
I have had several heads shaved and cc'd the combustion chanmbers on the JH. Stock is 8.5:1 static compression ratio. Original counterflow heads (mechanical lifter and hydraulic) are 29.5 cc volume for the combustion chamber in the head only (does not include the headgasket (about 7.6 cc for 1.8 bore, except the gasket has a 83 mm bore not 81.0) or the piston dish, or the small air gap between the top of the piston at TDC and the top of the block). the piston also has a slight area that is raised.
Milling the heads 0.030 inch or 0.45 inch presents no problems..only noticable improvements. Keep in mind that for every ) 0.010 inch milled off the cam retards about 1 degree. Retarding the cam about -3 degrees results in better top end (5,000 + rpm). I have gone 0.070 inch milled off and driven the car for years...with no problems. Calculting the compression ratio accuratly leads to about 9.0:1 compression at 0.070 inch. The rest you hear is bulls!4%^. Then I move the cam gear advanced 1 tooth (about 8 degrees) to compensate fro the excessive milling, which brings the cam timing back very close to "0". Also cams are ground with retard and advance built in (usually a few degrees) so ask before you buy cams. You will have to retard your ignition timing about 2 degrees due to the increased compression (if you had it optimized before).
PS I will post a intake performance test soon on ths site....
Yes, you are on the right path to enlightenment GRASSHOPPER..
I have had several heads shaved and cc'd the combustion chanmbers on the JH. Stock is 8.5:1 static compression ratio. Original counterflow heads (mechanical lifter and hydraulic) are 29.5 cc volume for the combustion chamber in the head only (does not include the headgasket (about 7.6 cc for 1.8 bore, except the gasket has a 83 mm bore not 81.0) or the piston dish, or the small air gap between the top of the piston at TDC and the top of the block). the piston also has a slight area that is raised.
Milling the heads 0.030 inch or 0.45 inch presents no problems..only noticable improvements. Keep in mind that for every ) 0.010 inch milled off the cam retards about 1 degree. Retarding the cam about -3 degrees results in better top end (5,000 + rpm). I have gone 0.070 inch milled off and driven the car for years...with no problems. Calculting the compression ratio accuratly leads to about 9.0:1 compression at 0.070 inch. The rest you hear is bulls!4%^. Then I move the cam gear advanced 1 tooth (about 8 degrees) to compensate fro the excessive milling, which brings the cam timing back very close to "0". Also cams are ground with retard and advance built in (usually a few degrees) so ask before you buy cams. You will have to retard your ignition timing about 2 degrees due to the increased compression (if you had it optimized before).
PS I will post a intake performance test soon on ths site....
1 - 12 of 12 Posts
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
