low end power issues, again
Discussion
I'd like to hear from any 4cyl Esprit Turbo owners, G cars in particular, to the low end power of the car. I brought this up about a year ago, but I've become annoyed with it enough to try again. My car seems to crawl off the line from a rolling start, and even if I release the clutch at up to 3000rpm, the car seems to launch pitifully (I don't want to dail in more revs than that, mostly to preserve my clutch and transmission). Yes, yes, I know the car was meant for higher RPM and was meant for handling rather than straight line acceleration, and yes, all hell does break loose above 3000rpm, but until then, it's PAINFULLY slow, slower than I could imagine from an exotic car like this. Plus, I've read a bunch of magazine and book articles that claim the Lotus 910 engine had relatively good low end torque. I did have my mechanic check this out himself about six months ago, and in his words, the car ran "ok", and managed to improve the car slightly by installing better spark plugs. I accepted that for a few months, but now I'm really becoming disappointed. I'm going to call my mechanic again tommorow, and have him check the car out again. Keep in mind I love everything about the car except for this percieved issue, and the car runs fine other than that. So if you own a non SE turbo, could you give me an idea of how your car performs, so I can compare it with mine? Also if there are any of you in Southern California, perhaps we could meet and drive each other's cars for comparison. If it turns out that this is not a defect in my individual car, I might be "forced" to trade up in the model line to an SE, perhaps. So could anyone who has driven both give their opinion on how much better the powerband on an SE is compared to an 86 turbo?
Thanks in advance,
Dan
editted to say: by the way, my engine just passed 50,000 miles a few weeks ago, and runs fine other than the problem, does not burn oil, etc. Also my car has Bosch Kjetronic and an upgraded turbo, not sure of the exact nature of the upgrade except that the turbo is now water cooled. Previous owner did claim that the low end power "crapped out a bit" after he swapped in the new turbo, I thought I could get this issue settled by taking my car in to the shop, but my mechanic didn't seem to think there was anything wrong with it so... Sorry for being long winded, any advice will be useful
>>> Edited by 86turbo on Monday 12th April 01:58
Thanks in advance,
Dan
editted to say: by the way, my engine just passed 50,000 miles a few weeks ago, and runs fine other than the problem, does not burn oil, etc. Also my car has Bosch Kjetronic and an upgraded turbo, not sure of the exact nature of the upgrade except that the turbo is now water cooled. Previous owner did claim that the low end power "crapped out a bit" after he swapped in the new turbo, I thought I could get this issue settled by taking my car in to the shop, but my mechanic didn't seem to think there was anything wrong with it so... Sorry for being long winded, any advice will be useful
>>> Edited by 86turbo on Monday 12th April 01:58
Sounds like the turbo addition might be the problem to me. If it's any bigger than the original T3 turbo then it will have a lot more lag with it.
I made the mistake of putting a bigger turbo into my S4 and had to change back as the thing was undrivable almost below 4k rpm.
The standard setup from the factory should be more than enough for you, and if not, chargecooling (i.e. going to an SE) is the way to go.
I'd check the turbo to find out what spec it is. If it's water cooled then it's definitley not a direct OE replacement for an non-SE and might in fact be an aftermarket "upgrade".
Also checking the wastegate is closed tightly and for vacuum leaks as these might account for slow boost build up.
michael
michael.
I made the mistake of putting a bigger turbo into my S4 and had to change back as the thing was undrivable almost below 4k rpm.
The standard setup from the factory should be more than enough for you, and if not, chargecooling (i.e. going to an SE) is the way to go.
I'd check the turbo to find out what spec it is. If it's water cooled then it's definitley not a direct OE replacement for an non-SE and might in fact be an aftermarket "upgrade".
Also checking the wastegate is closed tightly and for vacuum leaks as these might account for slow boost build up.
michael
michael.
My car does seem to have more lag than it should, the turbo doesn't spool up so instantly as I've heard it should. If it means anything, my boost guage needle begins to flicker at about 2700. When does turbo boost kick in on a stock car? I suppose a larger turbo would explain why max boost on my car is only .5 bar... I'll check the casting numbers on the turbo tomorrow, it was dark but I managed to make out some of the casting numbers '36' on the turbine side, and 'FCC' on the compressor side, don't know what that means, can't seem to find anywhere on the internet that tells me either. Can anyone explain, please? Also, I recently had more than a few of the vaccuum hoses replaced by my mechanic a few months ago when the car was running roughly, so I don't think that's the problem.
Dan
Dan
You likely have some wastegate issues with the larger turbo. Exactly 0.5 bar sounds suspicious - that is where it will go with a few different problems.
If you selected poorly with a larger turbo then you'll have a lot of lag. But, if you use a hybrid turbo, with a T3 turbine stage and a upgraded compressor you should not increase the lag very much while enjoying the benefits of a more efficient compressor, i.e, cooler intake temps under high boost.
If you selected poorly with a larger turbo then you'll have a lot of lag. But, if you use a hybrid turbo, with a T3 turbine stage and a upgraded compressor you should not increase the lag very much while enjoying the benefits of a more efficient compressor, i.e, cooler intake temps under high boost.
Hi,
You have me a little confused. You complain of low end power and then start talking Turbo boost.You acknowledge that it's a high rev top end car, but then complain because it's behaving exactly as it was designed to do.
Low end power is usually off boost power as there isn't really enough exhaust pressure to spool up the turbo to boost below 2500 or so. Boost coming on at around 2700RPM is pretty much normal.
Don't look for much power off boost in the low RPM range, torque is more what you'll get.
Low end is usually determined by ignition and cam timing and cam lift. If you want more low end, recurve the distributor to bring in full advance earlier, although by 2700 it should be all in. Also, setting the MOP to 104°, by swapping your stock 110° pulley for a 104 will add to the bottom, but only marginally. A lower lift cam will help, but at the expense of high end. It's all pretty much a trade-off. What cam are you running now? If the P.O. added a high lift cam, a popular mod, he did this at the expense of low end power. I have a 104 cam on my car (0.412" lift vs. stock 0.378") I gave away a small amount of bottom end, but got a great deal more after 2800 all the way to the limiter.
Simply adding a bigger turbo without addressing fuel supply (injectors) and Flow (Porting, Cam duration, lift and overlap, reducing Exhaust restrictions etc.) will actually impede an engine's performance rather than enhance it.
V8s typically have lots more low end grunt, courtesy of the additional 4 cylinders, which you don't have. Happy Motoring! ...Jim'85TE
You have me a little confused. You complain of low end power and then start talking Turbo boost.You acknowledge that it's a high rev top end car, but then complain because it's behaving exactly as it was designed to do.
Low end power is usually off boost power as there isn't really enough exhaust pressure to spool up the turbo to boost below 2500 or so. Boost coming on at around 2700RPM is pretty much normal.
Don't look for much power off boost in the low RPM range, torque is more what you'll get.
Low end is usually determined by ignition and cam timing and cam lift. If you want more low end, recurve the distributor to bring in full advance earlier, although by 2700 it should be all in. Also, setting the MOP to 104°, by swapping your stock 110° pulley for a 104 will add to the bottom, but only marginally. A lower lift cam will help, but at the expense of high end. It's all pretty much a trade-off. What cam are you running now? If the P.O. added a high lift cam, a popular mod, he did this at the expense of low end power. I have a 104 cam on my car (0.412" lift vs. stock 0.378") I gave away a small amount of bottom end, but got a great deal more after 2800 all the way to the limiter.
Simply adding a bigger turbo without addressing fuel supply (injectors) and Flow (Porting, Cam duration, lift and overlap, reducing Exhaust restrictions etc.) will actually impede an engine's performance rather than enhance it.
V8s typically have lots more low end grunt, courtesy of the additional 4 cylinders, which you don't have. Happy Motoring! ...Jim'85TE
Hi,
I think you've misunderstood me. First of all, I was not responsible for the turbo conversion, it was already done to my car when I bought it. Second, I think I didn't quite emphasize how much my car CRAWLS off the line. Until 3000 rpm, it is actually the slowest car I have driven. I simply want to know if this is normal or not.
I did not initially bring up the turbo conversion as the source of the problem (and as I stated I really don't know the nature of the turbo modifaction, and am looking into that), Michael is the one who brought up the possibility of an inept turbo swap, as on his car, and I simply commented on what I had experienced in my car.
I did not know exactly the extent to which the turbo boost affects the low end performance, because I had no idea how early the turbo would come on in a normal car. (Thanks to Jim, I now know that my car is about normal in this respect). Also, the previous owner stated that after he swapped the turbo, the car did run worse in low RPM which leads me to think, somehow, that this has something to do with what I am experiencing. Perhaps not the turbo itself, but something in that area (as has been suggested, the wastegate for example).
Admittedly I know very little about turbochargers and am currently trying to read up on them. Anyways, I've called my mechanic, and my car is going to the shop later this week, so hopefully I will have all my issues adressed soon.
thanks,
Dan
I think you've misunderstood me. First of all, I was not responsible for the turbo conversion, it was already done to my car when I bought it. Second, I think I didn't quite emphasize how much my car CRAWLS off the line. Until 3000 rpm, it is actually the slowest car I have driven. I simply want to know if this is normal or not.
I did not initially bring up the turbo conversion as the source of the problem (and as I stated I really don't know the nature of the turbo modifaction, and am looking into that), Michael is the one who brought up the possibility of an inept turbo swap, as on his car, and I simply commented on what I had experienced in my car.
I did not know exactly the extent to which the turbo boost affects the low end performance, because I had no idea how early the turbo would come on in a normal car. (Thanks to Jim, I now know that my car is about normal in this respect). Also, the previous owner stated that after he swapped the turbo, the car did run worse in low RPM which leads me to think, somehow, that this has something to do with what I am experiencing. Perhaps not the turbo itself, but something in that area (as has been suggested, the wastegate for example).
Admittedly I know very little about turbochargers and am currently trying to read up on them. Anyways, I've called my mechanic, and my car is going to the shop later this week, so hopefully I will have all my issues adressed soon.
thanks,
Dan
You need to drive another G car. That's the only way to know if your car is normal or not.
I drove a stock '86 a few weeks ago and thought it was just fine at the bottom end. Sure, it's slow but I've driven slower. Subjectively, I thought it was a little snappier off the line than my S4s (likely due to shorter gearing).
Tangent: a buddy of mine down in NoVa has an '82 Renault R5 Turbo II with a bunch of engine work done to it. He has to run a mix of 50/50 race gas and Sunoco 94. That is a car with no bottom end power. Off the boost, it is completely useless. It could barely maintain speed up a steep hill in 2nd gear at 25mph. On the boost: Yeee haaaaa!
I drove a stock '86 a few weeks ago and thought it was just fine at the bottom end. Sure, it's slow but I've driven slower. Subjectively, I thought it was a little snappier off the line than my S4s (likely due to shorter gearing).
Tangent: a buddy of mine down in NoVa has an '82 Renault R5 Turbo II with a bunch of engine work done to it. He has to run a mix of 50/50 race gas and Sunoco 94. That is a car with no bottom end power. Off the boost, it is completely useless. It could barely maintain speed up a steep hill in 2nd gear at 25mph. On the boost: Yeee haaaaa!
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