7A car to 3B engine

[Rocco]

hello guys.

i have a friend who "wish" to mount a 3B engine in he´s 2.3 20v coupe....

homologation it´s not a problem


wich will be the main mechanical parts that he will need??

-complete engine with manifolds,wastegate,turbo...

- 3B ECU

-turbo back sistem

the gearbox it´s the same true??? and the rear diff maybe yes too

someone made this the same project??? i think that it´s not to hard ..or not??



all small helps will be apreciated


-Tomas-

[20Vcqdriver]

conversion

Done this myself on my series 2 Cq (series on the work required started appearing in the Audi Driver magazine this month). Quite a lot of work involved but if you take your time it is not a major headache in the series 3 as a bit more room for tings like intercoolers etc and most of the loom is plug in and go, wheras I had to plug and splice, chop and change!!..

[Azman]

Straight swap matey, just take your time, or you could do two day swap like ala Wab and Az. We did it to my old CQ20 in two days, in feb, in the snow(well it was snowing otside the barn we were in), and feeling like extras from A River Runs Through it !!!!

Alll good fun and would do it again!!

[Rocco]

thanks for the info friends


my friend will take this next sunday all the engine + ecu + exhaust.... 1700€ for all

[stiglet]

Gearbox ratios are different from what i've heard (apparently you can hit 110 in 3rd on a 3B, only 90 in my 7a on the limiter) but the casing is the same so all will bolt straight up.

Rear diff is identical with 4.11 ratio.

He'll be adding a fair amount of weight too, not as much as he would with the ABY but still.... consider uprating the brakes if he hasn't already!

[Rocco]

Gearbox ratios are different from what i've heard (apparently you can hit 110 in 3rd on a 3B, only 90 in my 7a on the limiter) but the casing is the same so all will bolt straight up.

Rear diff is identical with 4.11 ratio.

He'll be adding a fair amount of weight too, not as much as he would with the ABY but still.... consider uprating the brakes if he hasn't already!

yeah¡¡

today i´ve discovered that the 20v gearboxes (nm /7a) have the same gearbox BUT the best of all will be the "shorter" gearbox ratios as you said very well.

i´ve calculated max speed in the S2 3b gearbox in 5 gear and if it goes to 7500rpm in 5 gear it does 285 REALLY km/h , and the 20v gearboxes does at 7500 around 245km/h max. other thing it´s that the 3B clutch i think that will fit 100% in the nm/7a gearbox because have the same diameter disc...

aniway i am not 100% sure about the front differential diamater in to the gearbox... maybe it´s diffent... S2 3b have i think 108mm and maybe the nm/7a the same or less like 100mm...

and other way will be to try "open" complete all gearbox and change if we can the gear "nuts" understund me??

sorry my english it´s poor



rear diff ratios yes, are the same in the nm/7a and 3b for sure


nice weekend for all

[stiglet]

The front and the rear diff ratios are the same, they have to be! So you are fine using the 7A Gearbox.

[20vQC]

Hola rocco! Mi coche era...y lo seguirà siendo hasta diciembre... un NM 2.0-20, es como el hermano directo del 7A 2.3-20. No te preocupes por las cajas de cambio porque tendran un encaje directo al motor sin problema alguno. Para mi mala suerte, la caja de cambios tiene las relaciones mucho mas cortas que la del 3B (3ra, 4ta, y 5ta marcha) y caminando a 100kph las rpm estan a alrededor de 3200 y tocarà los 260kph en el corte de vueltas de 7200rpm. Mi preparaciòn trabaja con 1.3bares de presion del turbo con todo original (excepto la centralita VEMS, escape hecho a mano con doble stage, y una panty media como filtro de aire, lo llamo filtro e' pu#@ hehe) y el coche puede lograr los 260kph en un corto lapso de tiempo relativamente.

Hey rocco! My car was ...and still being my car till december... a NM 2.0-20, is like the direct brother of the 7A 2.3-20. Don't worry about the transmissions cuz they're all a direct fit onto the engine w/o problems. For my bad luck the gearbox has some much shorter ratios than the 3b one (3rd, 4th and 5th gear) and running at 100kph (62mph) in top gear the revs are around 3200rpm, and will hit 260 (160mph) at the rev limit of 7200rpm. My setup is running 1.3bars of boost with everything stock (but VEMSecu,hand made exh with double stage and a panty air filter... bitchie filter is the nickname I gave it) and the car can reach 260 in just a relatively short time .

[anton]

yeah¡¡

today i´ve discovered that the 20v gearboxes (nm /7a) have the same gearbox BUT the best of all will be the "shorter" gearbox ratios as you said very well.

i´ve calculated max speed in the S2 3b gearbox in 5 gear and if it goes to 7500rpm in 5 gear it does 285 REALLY km/h , and the 20v gearboxes does at 7500 around 245km/h max. other thing it´s that the 3B clutch i think that will fit 100% in the nm/7a gearbox because have the same diameter disc...

aniway i am not 100% sure about the front differential diamater in to the gearbox... maybe it´s diffent... S2 3b have i think 108mm and maybe the nm/7a the same or less like 100mm...

and other way will be to try "open" complete all gearbox and change if we can the gear "nuts" understund me??

sorry my english it´s poor



rear diff ratios yes, are the same in the nm/7a and 3b for sure


nice weekend for all

your right about the front diff spline diameter, s2 is 108mm and 7a 100mm, you can change the splines over, but s2 driveshafts are harder to get hold of.

Ant

[Rocco]

Hola rocco! Mi coche era...y lo seguirà siendo hasta diciembre... un NM 2.0-20, es como el hermano directo del 7A 2.3-20. No te preocupes por las cajas de cambio porque tendran un encaje directo al motor sin problema alguno. Para mi mala suerte, la caja de cambios tiene las relaciones mucho mas cortas que la del 3B (3ra, 4ta, y 5ta marcha) y caminando a 100kph las rpm estan a alrededor de 3200 y tocarà los 260kph en el corte de vueltas de 7200rpm. Mi preparaciòn trabaja con 1.3bares de presion del turbo con todo original (excepto la centralita VEMS, escape hecho a mano con doble stage, y una panty media como filtro de aire, lo llamo filtro e' pu#@ hehe) y el coche puede lograr los 260kph en un corto lapso de tiempo relativamente.

Hey rocco! My car was ...and still being my car till december... a NM 2.0-20, is like the direct brother of the 7A 2.3-20. Don't worry about the transmissions cuz they're all a direct fit onto the engine w/o problems. For my bad luck the gearbox has some much shorter ratios than the 3b one (3rd, 4th and 5th gear) and running at 100kph (62mph) in top gear the revs are around 3200rpm, and will hit 260 (160mph) at the rev limit of 7200rpm. My setup is running 1.3bars of boost with everything stock (but VEMSecu,hand made exh with double stage and a panty air filter... bitchie filter is the nickname I gave it) and the car can reach 260 in just a relatively short time .

hehehe nice to see you speaking in spanish language

yo la verdad estoy contento con el S2 y su caja de cambios,aunque de todas formas me encantaria poder probar la caja del 7A/NM para ver los resultados en aceleracion.
Tengo entendido que en tu caja en 2ª velocidad llegando al corte ronda los 98km/h REALES ,asi como en el S2 3B en 2ª ronda los 112km/h reales tambien

me,really i am happy with my S2 and it´s gearbox but aniway i would can test the
7A/NM gearbox in to my s2 3b for apreciate the aceleration scores. i think that your gearbox at 7500rpm in second gear comes to really 98km/h, the audi s2 3b gearbox in second gear touch around 112km/h (the speedo always mark wrong)

[Rocco]

your right about the front diff spline diameter, s2 is 108mm and 7a 100mm, you can change the splines over, but s2 driveshafts are harder to get hold of.

Ant

hmmm i´ve supossed it,aniway with 100mm maybe it´s enough

[20vQC]

La verdad en mi caja en segunda llego a menos de unos 98 reales; tarè la aguja de velocidad mas acorde a la velocidad real desde los 80 (50mph) hasta los 130kph y la ultima vez que vi subiendo la aguja, a duras penas llegò a 95kph mas o menos pero venga, estamos allì!! No vì con tanta exactitud ya que de verdad subiò muy rapido al corte! hehe Pero sè que en 3ra llega solo a ~145, en 4ta a ~200 (velocidad real tomada con el GPS). En cuestion de dureza comparado a la del 3B no tengo idea, ha de ser igual de delicada que la caja del 3B que segun tengo entendido, el 90% tiende a romper uno de los ejes internos si se hacen arrancadas muy fuertes con frecuencia. Quizàs podrìa NO recomendarte mi caja si quieres mejores resultados de 0-100kph e incluso en el consumo de combustible, PERO sì si buscas buenos resultados en el 1/4 de milla o los 1000metros. Por cierto, mi limitador de rpm lo bloqueè a las 7200! Un saludo Rocco, espero te sirva de ayuda!!

On my tranny in 2nd gear it reaches a little less than some real 98kph. I've adjusted the arrow from the speedo to be more likely the real speed between 80 (50mph) and 130kph (70mph) and the last time I saw the arrow going up it has hardly reached 95kph (60mph)... but com'on, we are there! I didn't see with so much precision cuz it really got up fast to the rev limiter But I can say you that in 3rd gear reaches only about 90mph, in 4th ~125mph (real speed taken with the GPS). On resistance I don't have any idea if is as delicate as the 3B tranny, that as I know the 90% of them use to brake one of the internal shafts if hard standing starts are done with frequency. I maybe could NOT recommend my tranny if you want better 0-62mph and milage results BUT I do if you're looking for nice 1/4mile and 1000meters results. BTW I have blocked my rev limiter at 7200rpm.

[Rocco]

La verdad en mi caja en segunda llego a menos de unos 98 reales; tarè la aguja de velocidad mas acorde a la velocidad real desde los 80 (50mph) hasta los 130kph y la ultima vez que vi subiendo la aguja, a duras penas llegò a 95kph mas o menos pero venga, estamos allì!! No vì con tanta exactitud ya que de verdad subiò muy rapido al corte! hehe Pero sè que en 3ra llega solo a ~145, en 4ta a ~200 (velocidad real tomada con el GPS). En cuestion de dureza comparado a la del 3B no tengo idea, ha de ser igual de delicada que la caja del 3B que segun tengo entendido, el 90% tiende a romper uno de los ejes internos si se hacen arrancadas muy fuertes con frecuencia. Quizàs podrìa NO recomendarte mi caja si quieres mejores resultados de 0-100kph e incluso en el consumo de combustible, PERO sì si buscas buenos resultados en el 1/4 de milla o los 1000metros. Por cierto, mi limitador de rpm lo bloqueè a las 7200! Un saludo Rocco, espero te sirva de ayuda!!

On my tranny in 2nd gear it reaches a little less than some real 98kph. I've adjusted the arrow from the speedo to be more likely the real speed between 80 (50mph) and 130kph (70mph) and the last time I saw the arrow going up it has hardly reached 95kph (60mph)... but com'on, we are there! I didn't see with so much precision cuz it really got up fast to the rev limiter But I can say you that in 3rd gear reaches only about 90mph, in 4th ~125mph (real speed taken with the GPS). On resistance I don't have any idea if is as delicate as the 3B tranny, that as I know the 90% of them use to brake one of the internal shafts if hard standing starts are done with frequency. I maybe could NOT recommend my tranny if you want better 0-62mph and milage results BUT I do if you're looking for nice 1/4mile and 1000meters results. BTW I have blocked my rev limiter at 7200rpm.

OK thank you very much.

surelly the best choices for five speeds gearbox are the old 80´s ur-quattro gearboxes with less maximun speed than our gearboxes but stronger and more reliables