Advice needed sm inlet remap

[richardspeed10]

Had my car booked into efi yesterday and unfortunately Chris is saying something is holding the car back he’s had to pull back the vvt and lean it our after 6500k he’s suggesting it’s either the exhaust I.e damaged and restricting airflow or the timing but as the car is running perfectly up to 6500k he’s pretty sure it’s the exhaust. Anyone ever had a problem like this before?? Currently running a scorpion rs192 with de-cat with standard cams and sm inlet.

 

[imprezaworks]

@bloke

 

[simon_b]

That looks like a nice torque curve to me!
Why has he had to pull back the vvt and lean it out after 6,500 rpm, what happens if leave the vvt advanced and keep the AFR optimised?

 

[simon_b]

Or do you mean it made more power with vvt retarded after 6,500 rpm, and also by lean it out, do you just mean that the injector pulse width had to be reduced to keep AFR optimised? Do you have an AFR graph?

 

[richardspeed10]

Yes it made more power with the VVT retarded and the fuel leaned out after 6500, I’m pretty clueless when your asking from AFR graphs. He said it’s not breathing right and something is holding it back

 

[simon_b]

I understand, so if it’s losing air flow above 6,500 rpm, particularly with vvt advanced, high exhaust back pressure could cause this. I know that the RS192 (if it’s post 2014) has a 6” odd length of pipe upstream of the centre silencer that is only 2” diameter, so it’s possible that the exhaust is costing a bit.

You’re still making 184 bhp on I assume standard cams though, which doesn’t sound too far off, so even if the exhaust back pressure is costing you some airflow, it’s not costing a lot is it? What power were you expecting with this setup? What do others make?

 

[imprezaworks]

I’d be expecting 190 with the inlet.

Mine made 183/163 after the efi map, standard cams/inlet.

 

[simon_b]

The other thing you could check that might be hurting the top end power is if the SM inlet isn’t very well aligned with the head and there is a step between the inlet manifold and head ports.

And check that the air filter is nice and clean if you’ve not already checked.

 

[richardspeed10]

Chris showed me the results of a car he mapped earlier in the week with the same setup as mine standard cams and sm inlet and our graphs are identical until 6500, his keeps on pulling to 200bhp and the torque line is even till the redline where my starts dropping off after 6 and the bhp does after 6500, Chris is 100% something is holding the car back quite a bit could this possibly be timing

 

[richardspeed10]

I understand, so if it’s losing air flow above 6,500 rpm, particularly with vvt advanced, high exhaust back pressure could cause this. I know that the RS192 (if it’s post 2014) has a 6” odd length of pipe upstream of the centre silencer that is only 2” diameter, so it’s possible that the exhaust is costing a bit.

You’re still making 184 bhp on I assume standard cams though, which doesn’t sound too far off, so even if the exhaust back pressure is costing you some airflow, it’s not costing a lot is it? What power were you expecting with this setup? What do others make?

Any have you could show me a photo of the 6inch pipe your talking about pal

 

[bloke]

had one the other month with 197 cams that was the same top end, thought it was being held back, we knew cam timing was spot on so went with exhaust, didn't do back pressure test, possibly on standard cat and think it was scorpion system? stuck a pms manifold back on, back to tweak the map, gained a bit but not much at all. think it made just on 190bhp or near as.

 

[bashracing]

As Simon b has said the SM inlet needs port matching to the head but I still doubt it'll make any more power

 

[imprezaworks]

Any have you could show me a photo of the 6inch pipe your talking about pal

Not on the first date, no.

 

[simon_b]

^^^ LOL!
Yeah sure, if you look at the pic below, the bit I circled in red is only 2" diameter pipe. I know because I just bought one and it's currently on the work bench in my garage and I measured it. But like Bloke says, it'll not be worth a massive amount.

 

[simon_b]

One thing that would be really interesting to compare between the engines that make really good power and ones that don't is the air filter setup and more importantly, the intake pipe between the air filter and the SM inlet. The dimensions of this intake pipe can really influence the performance of an engine - not saying it definitely is in this case, just saying it can do, so would be interesting to see if people are running different setups.

 

[richardspeed10]

I’m running a 70mm pipe and a brand new ram air filter

 

[richardspeed10]

One thing that would be really interesting to compare between the engines that make really good power and ones that don't is the air filter setup and more importantly, the intake pipe between the air filter and the SM inlet. The dimensions of this intake pipe can really influence the performance of an engine - not saying it definitely is in this case, just saying it can do, so would be interesting to see if people are running different setups.

Do you think my battery cover could be causing any issues

 

[Chambers_RS]

Mine had a similar issue at efi about a week ago. But mines on a RS2 inlet. Chris had to add a lot of timing to even get the power upto standard. He thought compression was down or timing was out but I’ve checked compression and it’s spot on.

Chris checked the throttle body and check the air filter wasn’t restricting the air flow.
Not sure what else mine could be lol

 

[Aydon182]

Wheres your before run? if the car made 160 bhp before id be happy with the gain.
When people make the generalization that part a bolted on should = 190 bhp is when people start getting very upset, these cars dont all make the exact same power from factory, few cars do.
Ive never heard of the scorpion actually causing hinderance to a setup, it might not be the best performing system and a few bhp might be better gained off an alternative system but ive seen plenty of itb'd cars run over 200 bhp with the scorpion system.
The miltek system is probably one of the best ive seen its all sleeved with no pipe diameter variations, but it has 2 back boxes, the few bhp extra is worth the same as the weight saving of one box on the scorpion.
Just enjoy the car now, you're making peak torque at 2.5k rpm, thats ridiculous. Dont start spending out on things that dont need doing

 

[richardspeed10]

Mine had a similar issue at efi about a week ago. But mines on a RS2 inlet. Chris had to add a lot of timing to even get the power upto standard. He thought compression was down or timing was out but I’ve checked compression and it’s spot on.

Chris checked the throttle body and check the air filter wasn’t restricting the air flow.
Not sure what else mine could be lol

Have you checked the timing pal

 

[Chambers_RS]

Have you checked the timing pal

On GrpN timing so makes checking rather hard lol

 

[simon_b]

I reckon the timing is fine on Chambers_RS’s car because can see from his other thread that it’s making 160 ftlb which is good ... that’s the group n timing working.

 

[bloke]

On GrpN timing so makes checking rather hard lol

check it by eye...be easy :wink:

 

[Chambers_RS]

check it by eye...be easy :wink:

Haha will it?

 

[bloke]

Haha will it?

yeah, it's how i made my timing tool for the 197 cams :tonguewink:

 

[Chambers_RS]

yeah, it's how i made my timing tool for the 197 cams :tonguewink:

Ok I’ll grab a picture for you to cast your eye over :tongueclosed:

 

[bloke]

Ok I’ll grab a picture for you to cast your eye over :tongueclosed:

make sure it's wonkey...