1.6 N/A With 1.6TD Tans.

[91jettaidi]

Hello all I searched for this info on here but had no luck. Maby I'm just dumb. So I have a 1990 Jetta with a 1991 Turbo Diesel 1.6 on the garage floor and a 1992 1.6N/A powering my Jetta currently. Now on the highway of the TD when doing 100Kph or 60Mph it turns over 2,500RPM the N/A at the same speed just shy of 3,000RPM. Can I take the 5th gear at put it into my N/A transmission just so I don't feel like I'm killing the poor thing. I know I'm not but it sounds like it. Thanks.

[vdubspeed]

you can definitely swap the 5th gear which would be the easiest thing to do.

Here's a good link:

http://www.brokevw.com/5thswap.html

[91jettaidi]

Great thanks. Also what if i just swap in the TD transmission would it be better for a N/A city wise?

[R.O.R-2.0]

Great thanks. Also what if i just swap in the TD transmission would it be better for a N/A city wise?

the higher revving trans would allow the best mileage in the city..

ive had a handful of different 4 and 5 speed trannies in my rabbit.. the best performing for city mileage were the GC 4 speed, and the AUG 5 speed..

the 4A did alright, but still left something to be desired.. it was like driving a 5 speed with a blown up 4th gear.

the ACN was GREAT, but it didnt get as good of mileage in the city..

you may want to leave the trans in your n/a thats in it now.. 600 revs @ cruising speed may very well bring it right out of its powerband, and make it lug, rather than actually get you gains..

what code is the trans you want to swap in your car? what trans is in there now?

[91jettaidi]

yea, thats what i was thinking to. Um ill have to go dig it up ill post it as soon as i know

[R.O.R-2.0]

basically, what i was saying in my first post, is that the trannies that allow the engine to rev a bit, seem to get the best mileage, because the engine is using barely any fuel.. it may be turning more RPMS, but its working less hard to turn those higher RPMS.. lower revs could result in higher fuel consumption, because of lugging the engine..

FWIW, a VW diesel with a stock governor, stock fueling, and a good cooling system.. you could fire it up, lay a brick on the pedal, and the engine would rev out to the top of the governor ALL DAY LONG with no damage.. the only thing that would kill the engine, is running out of fuel.. these are tough engines, and turning them 3-4 thousand rpms is safe, literally all day long.

look at the old diesel rabbits, the first ones ALL HAD 4 SPEEDS, and most of them were the low geared 4 speeds that would only allow you to go 83mph on the governor.. those rabbits all got good mileage.. some people claim the 4 speeds get you the BEST mileage.

anyways, i wouldnt do anything till i figured out what tranny codes you were dealing with.. almost sounds like the 91 TD may have an ACN attached to it, judging by the rpms @ 60 mph..

an ACN trans, (or something high geared like that) probably WONT get better mileage than a slightly lower geared trans..

[91jettaidi]

Well thats great info to hear. I know there tough but I'm always second guessing when I'm cruising at 120km and turning over a conservable amount but i was going to add a giles pump then maby add that 5th gear but I'm still going to check out those codes. Hahaha thats why i love n/a's there meant for work i do hold it quite high on the highway some times but i do baby her in the city and never boot her up a hill.

[BigVWman]

Should double check the ratios and make sure its the 5th gear that is the difference, it could be final drive ratio making the difference!

[91jettaidi]

So just for ***s and giggs I could hold that engine at full throttle 130-140ish for a while and it won't excessively ware the engine?

[8v-of-fury]

Should double check the ratios and make sure its the 5th gear that is the difference, it could be final drive ratio making the difference!

Very true, we need the ratios before any advice can accurately be given.

So just for ***s and giggs I could hold that engine at full throttle 130-140ish for a while and it won't excessively ware the engine?

If everything is stock and nothing has been messed with yes. You could set the car in neutral and hold the pedal to the floor until you ran out of fuel. With the stock governor in the pump it will only allow the engine to reach 5300rpms (+/-50). This isn't a Honda your talking about vw engines were built to withstand high rpms.

[R.O.R-2.0]

Should double check the ratios and make sure its the 5th gear that is the difference, it could be final drive ratio making the difference!

Very true, we need the ratios before any advice can accurately be given.

So just for ***s and giggs I could hold that engine at full throttle 130-140ish for a while and it won't excessively ware the engine?

If everything is stock and nothing has been messed with yes. You could set the car in neutral and hold the pedal to the floor until you ran out of fuel. With the stock governor in the pump it will only allow the engine to reach 5300rpms (+/-50). This isn't a Honda your talking about vw engines were built to withstand high rpms.

stock governor is around 4800... TD governor is 4850..

[8v-of-fury]

Nope, straight from Giles in an email between him and I. 5300 for the NA and 5350 for the TD.

[keaton]

easiest solution: add a turbo to your NA and turn the IP screw up.....

[R.O.R-2.0]

Nope, straight from Giles in an email between him and I. 5300 for the NA and 5350 for the TD.

then why do all the other sources say otherwise? i have a FEW manuals that claim 4800/4850

you guys are the only ones ive seen claiming 5300/5350.. are you sure thats not AFTER the gov mod? my engine has a tough time even turning that high in neutral, i have the gov mod done, and my fuel CRANKED UP.

this is completely pointless tho, and has nothing to do with this thread..

starting another thread, see you there Jeremy!

[91jettaidi]

Um well god didn't intend my Non turbo to have one so thats a no no and if you look at the cluster I'm pretty sure that 4,000-4,500 is a doted red for the red line then after 4,500 its a solid red I'm sure mine cuts off at the solid red.