# What's the rev limit on a Mk2 GTI 8V?



## GTIspirit (Dec 13, 2002)

I'm having a hard time finding an answer to this question on the web or in these forums.  

What is the rev limit on a Mk2 GTI 8V? Specifically a GTI 8V that is equipped with CIS-E, aka, KE-Jetronic. I'm thinking the answer might be about 6600rpm but I'd like to hear confirmation for sure.


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## ziddey (Apr 16, 2006)

beyond the point when you should shift 
before the point the engine is endangered 
rev away 
if you've never felt the rev limiter kick in, brace yourself.


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## WaterWheels (Aug 14, 2005)

It is advertised at about what you posted. I can't recall the exact speed listed but it is a plus/minus range of about 200RPM either side of the speed in the manual if I recall. Still can never understand the big deal with engine speed limits. Everyone is always wanting to know what they are and how to change them, but never give any reason as to why


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## GTIspirit (Dec 13, 2002)

Thanks for the confirmation. Yes, the fuel cut hard rev limiter is a real b!tch. Sometimes I'd rather not shift out of 2nd on an autocross course with my '87 GTI 16V but the hard rev limiter kicking gets in the way. I think it's probably much better for the engine to rev to 7500rpm than have the fuel suddenly cut and then re-engage, cut and re-engage.


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## Glegor (Mar 31, 2008)

my GTI rev limiter is at about 6300. and it seems to pull till your almost at the limiter.


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## WaterWheels (Aug 14, 2005)

> Yes, the fuel cut hard rev limiter is a real b!tch.


 CIS-e is really soft compared to ignition cut-offs like on the KR code 16v


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## GTIspirit (Dec 13, 2002)

Um, it's pretty harsh on the PL code 16V after blowing through the soft rev limiter in the knock box. I don't know how a complete reversal of DPR current and subsequent closing of the DPR valve could be considered "really soft....."


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## Glegor (Mar 31, 2008)

cis-e cuts the fuel by turning the fuel pump relay off... the rev limiter is in the fuel pump relay isnt it?


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## WaterWheels (Aug 14, 2005)

No it is not and does not. The limiter is built into the knocksensor control unit and when it reaches the engine speed limit the signal it sends to the fuel ECU causes it to change the mA signal to the diferential pressure regulator. This does not shut off fuel, but cuts it back (negative mA) and is much softer than others in the past which just kill the ignition in an on/off cycle based on the engine speed. That is why people who have hit the limiter in CIS-e cars say it feels like the engine just goes flat, but not as smooth as EFI systems.


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## GTIspirit (Dec 13, 2002)

I don't know anything about a hard rev limiter in the fuel pump relay as that is not what my car has. CIS-E, at least the later KE-Jetronic, does in fact have a hard fuel cut rev limiter. Negative DPR current does in fact close the DPR valve, it's explained in the yellow covered Bosch technical manual on the KE-Jetronic. 

For those of you who can read German, I have an excerpt from this KE-Jetronic technical manual, auf Deutsch, which explains the point. 








It is so, I have dyno data to prove it.


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## WaterWheels (Aug 14, 2005)

First I have to say that yes, I can read German. Second I also have to point out that although I can't seem to locate that drawing, I believe it came from a basic CIS and not a CIS-e manual. It might have been posted in many manuals as it is more or less a generic example of how a simple limiter works, I'll look to see if I still have it. But all that aside as it really does not matter, I think you're reading too much into the quoted words. "Ein" and "Aus" do not directly translate always into "On" and "Off". It could mean in and out as well, but again this is a mute point as the results are about the same. The real important point to notice in that drawing, and that's their point as well, is the revolution information. If you believe that a fluctuation of injector fuel in an 80RPM (yes eighty) space equals a "Hard Limiter", then you have never dealt with a true hard limiter. I have worked on engines that bounced hundreds of revolutions per minute in short periods and never felt all that punishing. 

As for CIS-e and the limiter, which the above drawing does not depict, fuel is never "shut off". A negative mA signal does reduce fuel at the injectors and can reduce it down a long way, but it does not shut off fuel. If that were the case then when coasting down a long hill at speed with the idle switch closed the engine would die from lack of fuel. The ECU sends a negative mA response to the DPR the entire time until the engine speed lowers to a set RPM (something like 2500) to resume normal mixture. Do the same thing and kill the fuel pump or shut off the ignition and the car would coast to a short halt because the engine dies instantly. 

Also? You began asking about an 8V, or so you posted and then continue about a 16V. The 16V limiter in the PL is not at 6600RPM but I believe more like 7200RPM. Much past the engine speed where any additional power is being produced.


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## Glegor (Mar 31, 2008)

ok, sorry, i was just told that CIS-e had the limiter in the fuel pump relay. it doesnt feel like it shuts the fuel pump off at first, just kinda flattens out. but if you over rev it too bad, it flat shuts the engine off for a second... first time i hit it, i thought i broke something, thats how hard i hit it.


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## WaterWheels (Aug 14, 2005)

Glegor said:


> . . . but if you over rev it too bad, it flat shuts the engine off for a second...


 Maybe I'm just to picky, but this really makes no sense if you think or know about it. The limiter will not allow you to "over rev it too bad". Once it reaches the limiters setting, the engine will not go any further, that's the end of the engine speed increase. You can get to is fast or slow, but once there, your there and that's all she wrote.


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## Glegor (Mar 31, 2008)

ok, well is what im saying is that i blew thru the rev limiter, the engine had enough momentum that it revved higher even after i let off the throttle. tach made it all the way to 7 grand. i was in 1st gear too, so the engine didnt really have any load on it to keep it from revving any higher. i missed 3rd gear, and i was wound out pretty good already in 2nd too. and i meant to say it "feels" like it shuts the engine off. im not saying your knowledge is wrong. i have no doubt you are right actually. i dont pay attention to stupid things like rev limiters, i focus more on things that make my engine go faster, not keep it from going faster. lol..


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## GTIspirit (Dec 13, 2002)

WaterWheels said:


> As for CIS-e and the limiter, which the above drawing does not depict, fuel is never "shut off". A negative mA signal does reduce fuel at the injectors and can reduce it down a long way, but it does not shut off fuel. If that were the case then when coasting down a long hill at speed with the idle switch closed the engine would die from lack of fuel. The ECU sends a negative mA response to the DPR the entire time until the engine speed lowers to a set RPM (something like 2500) to resume normal mixture. Do the same thing and kill the fuel pump or shut off the ignition and the car would coast to a short halt because the engine dies instantly.


 Thanks for confirming the 8V rev limit, I did need to know that value. It seems that my simple question has opened further discussions on KE-Jetronic operation. I am trying to explain some of the intricate details of the function because everyone benefits by having a better understanding of the system. 

I think there are a lot of misconceptions on the internet regarding K-Jetronic and KE-Jetronic operation because there were so many variants. I'm specifically referring to the function of the later KE-Jetronic variant found in the PL engine code, sometimes referred to as KE2.5-Jetronic. I don't know if my statements also apply to the earlier KE-Jetronic versions, sometimes referred to as KA-Jetronic. 

Read the yellow covered Bosch KE-Jetronic technical manual, it's all explained there. A negative mA current really does close the DPR valve. This is confirmed verbatim in that manual. And exactly as you said, when coasting down a long hill the fuel is in fact turned off on KE-Jetronic. This was an advancement over K-Jetronic to save fuel and reduce emissions. If you install an Innovate LC-1 or similar you can very clearly see this behaviour as the engine goes full lean when the idle switch is engaged during coast down. Fueling is resumed as a function of coolant temperature and engine rpm. 









As to why the engine doesn't "die" when coasting down, actually, it does, you just don't notice it because the clutch is engaged and the wheels are turning the engine over. Once the engine rpm drops far enough the injections will resume before the engine stalls.


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## MKIGTITDI (Aug 25, 2007)

See this limit thing intrigues me now i can pull my motor all the way past my 7k thats indicated and it never hits any type of limit. Would this have anything to do with having an ABA(OBD1 block) with a 1.8l solid lifter head running on CIS basic? I have tt heavy duty valve springs and a tt 276/280* cam in there. So Any clues on that one?


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## WaterWheels (Aug 14, 2005)

OK, yeah that's where I saw those graphs, in the booklets. They used to be given for free by VW if you asked for them but stopped some years ago. In fact they no longer have any email addresses to ask questions through, shame. Anyway I trashed those Booklets a few years back. But either you are reading too much into words like "close" than is really there or misunderstanding some things altogether. Positive and negative mA move the plate valve away and towards the hole in the DPR, that is true and how it controls lower chamber pressure. It does not, nor can it due to the design, cover the hole completly and some fuel will always flow through. That your LC-1 indicate maximum lean is fine, it can get real lean, but fuel is always getting through. Sit back and think of the issues you would run into if zero fuel were present for say 5 or 10 seconds coasting down a long steep hill and then all of a sudden fuel is injected back in. And even if the hole were to become cover and the lower chamber pressure was then frozen, the system would act more or less like a basic CIS system in that if the air sensor plate is raised it allows fuel through. Coasting down a hill even with the throttle closed will draw some air into the engine and lift the plate a little and the spring in the lower chamber will not raise the metal shim high enough to close off the port leading to the injector, it just can't happen. Please don't base any "I know I'm right . . " statements on pictures (drawings) in those Booklets or any other manual, they are just to explain the principle of operation. 

If confusion is what you were trying to accomplish by posting the second graph, you did it. It has zero to do with the discussion here, or maybe you don't know just what a "Schubabschaltung" really is? And if that came from the same Booklet as the other, I can't remember, then it does more to confirm my point of the graphs just being "raw" examples of things as that part is only found on the Basic CIS System, at least with VW. 



GTIspirit said:


> As to why the engine doesn't "die" when coasting down, actually, it does, you just don't notice it because the clutch is engaged and the wheels are turning the engine over. Once the engine rpm drops far enough the injections will resume before the engine stalls.


 Com'on, you don't even believe that yourself now do you? Coast down a nice steep hill with the engine running, the throttle closed and foot on the brake one time and then do it again but the second time kill the engine or just the fuel if you can. Then come back and say they both rolled the same and the second time the car didn't come to a quick standstill. I live on a hill and often use it to "jump start cars" for one reason or another. Even after letting it roll for half the hil or more if I let the clutch out the car chugs a time or two and stops dead, ain't no "wheels rotating the engine" for very long.


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## Glegor (Mar 31, 2008)

i dont think CIS basic has a limiter.. yours for sure does not if you can hit over 7 grand.


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## WaterWheels (Aug 14, 2005)

It would appear that I've been away from CIS systems for too long and have to backpedal or retract some of what I've said (to GTIspirit that is). Might have been a good idea to follow my own advice and sit down and think about it a little better. I had been looking for the booklet for KE-jetronic on the Internet and found an English copy in PDF format. Downloaded it and began reading. In doing so it became clear that you, and I, were correct (more you than I though as for the stoppage of fuel to the injectors). The DPR as I stated can not completely shut off fuel to the lower chamber, but the springs in the chamber are strong enough to close the outlet ports when the lower chamber pressure gets down far enough. Who would have thought some tiny springs could cause so much problems  It also seems that due to the narrow engine speed at which it bounces and the fact that it is a "continuous" system, the effects are soft enough on recovery to a) cause a smooth transition and b) not harsh enough to cause any damage. Guess going back and reading some of the stuff I tossed to the side would be a good idea once in a while. 

The graphs are a different story. While searching I came upon the second graph used no less than three times in three different injection systems, one being an EFI system. The words were changes to some degree but the graph was the exact same. That kind of goes for the first graph also, saw it at least twice also under different injection systems. So I still advise using them only as an example of how a simple limiter works and not as the Gospel for KE systems. By the way, Schubabschaltung is a deceleration valve, it is used on Diesel and gasoline engines and the only VW engine I know of that used it was the 16v KR engine. Other basic CIS engines may have used it also, but it deverts intake air from under the air sensor plate to the intake track hense dropping the air sensor plate during coasting. 

Have to say that my "example" of shutting the engine off while coasting down hill was, in a word, dumb. I have no excuse for using such a off base example, and it is in no way the same as what the limiter does dueing coast down. Next time you notice me starting to talking out my rectum, don't wait so long before telling me to "sit down and think about what you're saying".


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## EL DRIFTO (Jul 11, 2004)

rev limit all depends on which specific vehicle
so i'll guess:
in 77 (cis basic) it could of been the rotor on other aircooled, otherwise they had none, i've seen the tach in the gas guage, but the cis pumps have ALWAYS been turned on, only if the engine is spinning, by a logic circuit somewhere, connected to the ignition, to tell if the engine is sparking & only then should the pump run.

so the rev limiter is in that technolgy, wherever located

so in an 87 fox, since it doesn't have knock sensor technology to tell it to go on, but it's cise, it has the old shcool relay & rev limiters in the relay, you can change it to earlier scirocco relay & no rev limiter now

in 87 golf, all had knock sensors, so that technolgy (cis e), the knock brain turns on a simple, large pin, plain old relay. & changing the knock brain to 16v is the only way i know to change it, then the ignition curve is off, but it can work

in 87 16v scirocco hits the rev limiter @ 7100 in fifth gear, it appears to pull a little timing there, keeping it


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## laundryhamperman (May 15, 2010)

A little off topic and possibly obvious at this point, but if one were to take the ignition system from the KE-Jetronic A2 and install it on a CIS-Basic or CIS-Lambda system, there effectively is no rev limiter as the knock box does not communicate with any fuel components on say, an A1 GTI? Point is for people looking to install the knock box ignition on older cars, will there be a rev limiter?


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## teknikALLEN (Jul 14, 2010)

fuel pump relay part #321 906 059E with NO REV LIMITER with a knock box from a 86 Jetta Carat part #811 907 397 F for 8v CIS-E

how about CIS with out a knock box?


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## Glegor (Mar 31, 2008)

teknikALLEN said:


> fuel pump relay part #321 906 059E with NO REV LIMITER with a knock box from a 86 Jetta Carat part #811 907 397 F for 8v CIS-E
> 
> how about CIS with out a knock box?


i havent found the rev box on my CIS-lambda car, its an 86 golf, and ive spun it clear to 6500, while still making power 

my GTI would shut off just as the tach needle was touching the red.

im kinda thinking that i have one of those special limiter-less fuel pump relays..

also, if you wanna get rid of the rev limiter in the fuel pump relay, just throw a horn relay in there!


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## TheMajic86GTI (Aug 9, 2009)

I had this conversation last year with the guys at TT. They said it has 2 limiters, the ecm and the fuel relay. Their advice was to change out the 8v ecm #0280800140 to the 16v ecm #0280800180 and call it a day! You'll go from 6300 to 6700rpm. Removing it completely was dangerous cuz it overides the fuel cutoff and if you got into an accident it wouldn't shut the fuel pump off according to them but dont know the whole truth behind that.....


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## ziddey (Apr 16, 2006)

The ignition timing curves are different between the 8v and 16v knock boxes, with the 16v being a little less aggressive IIRC. It may be for the better, since we'd be able to advance the base ignition timing.

For people who don't have the knock box setup and want a higher rev limit without using a horn relay (for dangers TheMajic86GTI pointed out), you can use the fuel pump relay from a 5cyl audi/vw without knock sensing. Rev limit will effectively be in the 7000's.


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## Glegor (Mar 31, 2008)

TheMajic86GTI said:


> I had this conversation last year with the guys at TT. They said it has 2 limiters, the ecm and the fuel relay. Their advice was to change out the 8v ecm #0280800140 to the 16v ecm #0280800180 and call it a day! You'll go from 6300 to 6700rpm. Removing it completely was dangerous cuz it overides the fuel cutoff and if you got into an accident it wouldn't shut the fuel pump off according to them but dont know the whole truth behind that.....


yes, if you install a horn relay, the pump runs when the key is on.. there is no wire there to signal that the engine is not running, or is running too fast..

when the engine is not running, and when it runs too fast, the fuel pump shuts off..


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## WaterWheels (Aug 14, 2005)

I believe some have to go back and research engine speed limiters for Volkswagen engines/models. Three different types were installed from the beginning of the watercooled models. Ignition cut-out, fuel pump cut-out and mixture alteration (for lack of a better term), but no vehicle used more than one type. Installing a different relay, like a horn relay, on a CIS-e car will not effect the engine speed limiter. Yes it will delete the safety function, but the engine speed will still be limited.


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## ziddey (Apr 16, 2006)

Stateside, there's select 85 a2's and 87-90 foxes that had cis-e without a knock box, where the rev limit is controlled by the fuel pump relay.


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## WaterWheels (Aug 14, 2005)

ziddey said:


> Stateside, there's select 85 a2's and 87-90 foxes that had cis-e without a knock box, where the rev limit is controlled by the fuel pump relay.


Yes, and that was one of the limiters I stated. It just seems, and there is a lot of clutter in the posts, that some are thinking that multi-limiters might be in play. Maybe just reading things wrong so my post really was just to clear up what could be used in a vehicle but not more that one of them. Like in the "original new" question about the knock box installed on an older A1. Although the knock box is what limits the CIS-e (non Fox) systems, the pump limiter is what will still be in place unless it is changed.


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## Glegor (Mar 31, 2008)

WaterWheels said:


> Yes, and that was one of the limiters I stated. It just seems, and there is a lot of clutter in the posts, that some are thinking that multi-limiters might be in play. Maybe just reading things wrong so my post really was just to clear up what could be used in a vehicle but not more that one of them. Like in the "original new" question about the knock box installed on an older A1. Although the knock box is what limits the CIS-e (non Fox) systems, the pump limiter is what will still be in place unless it is changed.


ok, i have an 86 Golf, it has CIS-lambda, i have not found a rev limiter yet. if it has a rev limiter, what type would it be? fuel cut? or does it even have one? i have not messed with anything on the fuel or ignition system, so it is as it came from the factory, as far as i know.


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## mikefu (Jul 26, 2010)

this is what it looks like and mine is before the needle goes into the red. Its pretty harsh. Mine is an 86 cis -lambada as well


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## TheMajic86GTI (Aug 9, 2009)

mikefu said:


> this is what it looks like and mine is before the needle goes into the red. Its pretty harsh. Mine is an 86 cis -lambada as well


It should be 6300 rpm....


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## Glegor (Mar 31, 2008)

TheMajic86GTI said:


> It should be 6300 rpm....


im gonna have to go out and find out today.. i know my GTI had one at 6300 with CIS-e

amazingly, my CIS-lambda car pulls more RPMS than my GTI does.. my GTI fell off power at like 5500 with a 268 cam, this one has useable power clear to 6k, on a stock engine, with the catalytic converter intact..


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## ziddey (Apr 16, 2006)

maybe the tach gets as inaccurate up top as the speedometers?

with the stock fuel pump relay in my fox, I'd hit cutout at 5900rpm, according to the tach.


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## Glegor (Mar 31, 2008)

ziddey said:


> maybe the tach gets as inaccurate up top as the speedometers?
> 
> with the stock fuel pump relay in my fox, I'd hit cutout at 5900rpm, according to the tach.


ive verified that my tach is close enough for my likings.. 100 rpms off is nothing big..

at 6k rpms on my auto meter tach, it was turning 6100 on the dash tach..


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## Jettaboy1884 (Jan 20, 2004)

MKIGTITDI said:


> See this limit thing intrigues me now i can pull my motor all the way past my 7k thats indicated and it never hits any type of limit. Would this have anything to do with having an ABA(OBD1 block) with a 1.8l solid lifter head running on CIS basic? I have tt heavy duty valve springs and a tt 276/280* cam in there. So Any clues on that one?


What car?

I had an ABA crossflow in my old '83 GTI (I believe that it was CIS Lambda?) and I could run it to ~ 7200 before the engine would feel like it was going to vibrate to pieces. It was most likely the hydraulic lifters pumping up and floating valves, as I was running the stock ABA valvetrain...

So, you shouldn't have an issue running a solid lifter head with HD springs a bit over 7k. Do you have any head port work to flow up there?


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