8 replies to this topic

[orac69]

Hi, I have a 94 SPi, with a couple of minor tweaks done by the previous owner - K&N, a decent exhaust, bigger wheels.  AFAIK the engine, gearbox are standard.  Its a DAM5626 box - unknown final drive but I dont think the engine has been out of this car so reckon its standard.

 

Im a hobby mechanic, and know very little about the spi apart from what ive read here. Ive never been in another one, and dont know anyone in my area who has one.   I know tuning spi is quite hard with the ecu, fuelling etc. compared to carb cars.

 

The car runs great, its had all the vacuum lines done, intake manifold refurbed, all new sensors inc lambda - it starts, runs, drives great EXCEPT that it totally runs out of steam at about 4000 rpm in any gear.  Just wont rev higher.

 

I have a ECU cable / mems software on a laptop and to my untrained eye all looks in normal ranges.

 

So my question to you guys is is this normal max rev / power for an SPi, or am I being unrealistic to expect it to be doing more?  If it should be doing more, where do I start to troubleshoot.  I dont expect rally car performance out of this small lump, but thought it might go a bit higher.

 

tia !

Edited by orac69, 06 January 2025 - 11:46 AM.

[absx2]

Considering it produces 62 bhp at 5700 rpm there seems to be something wrong there.

 

Hopefully someone with SPI experience will come along soon, does the car hit a rev limiter at 4000 rpm or just doesn`t pull any more revs even in second gear for instance.

It should be fairly easy to hit 6000 rpm in second gear if you`re beating it :) 

[viz139]

I have the low compression 50 bhp SPi. I brought my daughter on a track day when she passed her driving test. At the start  had to keep telling her to hold the gears not to change up too soon. By the end of the day I was shouting at her to change as she rag it out to the limit in second it was up near 6k in third.  Even on a long motorway you won't pull much over 5k in forth, not enough power. You may want to check the fuel filter, I've seen several high mileage injected minis still on there original fuel filter. Add an injector cleaner to your next tank of petrol.

[brivinci]

Yes, an SPi should rev pretty freely to nearly 6k, if you let it. Maybe not in forth but all the rest. I would do a compression test and maybe see what the oil pressure is looking like to make sure you didn't spin a bearing. 

[genpop]

Like Viz said change the fuel filter, change the air filter too..

Have a logfile by means of your diagnostic software and publish it here.If you cant upload it rename it a txt file then it willbe uploaded.But first change the filters.

[orac69]

Thanks for the info all.  It doesnt hit a limiter, just wont pull / rev anymore past 4ish..  

Its on 42k miles so not a high mileage car.

I'll change the fuel filter, compression test and will upload the logs once it back on the road - its currently in the air getting new suspension, hilos etc..

Edited by orac69, 07 January 2025 - 12:44 PM.

[DeadSquare]

It is not normal for an A series to run out of Puff at 4,000 rpm.

 

The specification of the valve springs on the A35 A series engine, was intended to limit the RPM, well within the stress tolerance of the engine's capability, by inducing "Valve-bounce" at about 6,000 rpm.

 

Why, after over four decades of successful amateur and Works competition experience,  would the engine be deliberately limited to less than 6,000 rpm ?

[coopertaz]

is the fuel pressure correct? if so could try running some injector cleaner through to see if this helps

[orac69]

Thanks everyone, I didnt think 4k was going to be "it".   Injector removed sent off for cleaning / testing, new fuel filter ordered, will report back with an update in due course.