200whp with stock N/A rotating assay? by ForcedFirebird

By diyauto
( 1 )

200whp with stock N/A rotating assay? 

Compliments of ForcedFirebird @ http://www.r3vlimited.com


Title says it all. How close do you think we can get to 200whp N/A with only exhaust, head work, induction and a good factory bottom end?


With the higher compression Euro motors?

Yes, plan is cam, over-sized valves, porting, ITB's, mid length headers with an x and dual exhaust.

Digger, what says PipeMax about the placement of the x pipe? I have Dynomation, and have been meaning to get PipeMax just to help with exhaust.

Here is the subject:

Not going to stop the effort

Rama saw 178whp with ITB's on a stock high mileage engine. Oh yeah, since this is a stock Spec e30, gonna throw your tune on it for back to back comparisons.>

No lying, non biased, facts are facts kinda gig. Same day, same dyno, same car. Let's just see what squid has to offer! I'm going to say minimum 5whp from chip alone....

YES! Will keep you posted. We are in this thing together. Without all this development behind the scenes, and helping each other out, this community would be dead. Let's keep the m20 alive! 24v swaps For The Loss.

Tune can be significant pending what's wrong/right with your hardware. 100% healthy m20 is going to be 150-ish whp. Through dyno testing typical ebay headers are lucky to see 5wtq, no peak HP change with single 2.5"

Still made in China and have lots of copies. These headers are similar to what you are talking about. 24-30" primaries.

Not many m20 enthusiasts are willing to pay $1 plus for proper headers. I have been sitting on my "180 degree" headers for 2yrs plus due to price.


Dyno day. Run 1, pulled on dyno as it sat. Run 2 cut the P/S belt. Run 5 is Sssquid's file. Pretty sure this engine has never been opened, if it did, it was eons ago as the head is pretty filthy inside.

That happens because the ECU stops reading higher RPM's before the rev limiter and the last block in the maps are carried through for fuel/spark. That can be changed, but since this was a Spec e30, it had an unopened ECU.

This was your OEM performance tune, very surprised the AFR's were so behavioral. Client put 19's in and been driving it, and was surprised it had adapted that much - still the common BMW lean conditions.

Idles and drives like junk though, just like everyone else who puts bigger injectors on without a matching chip. Didn't want to waste time dyno tuning this motor, already showed low power.

Best to date on an all stock motor was 157whp header and exhaust only car. It has the Racing Dynamics headers, true merge collector in reverse to a Vibrant 2.5" resonator, back to true merge into a Billy Boat rear section, OEM induction, cam, rebuilt head, dyno tuned.

Everyone loves pic, right?


No argument besides the manifold (ie head to TB design) is at play here. Would your view change if the Jenvey setup made more? Not playing sides here, BUT, am a small independent shop in South Florida who really is testing stuff.

Rama, one day is fine, the next is black. Let's get 'er done. Would love to run your kit for no better reason than you are a gent like me.

Just put a locals' tune up, as mentioned, it is what it is. No hold barred. My job is to deliver to the client.


After installing the Rowland manifolds and Extrudabody ITB's on another customer car and had to do a booster delete. This client and I have decided to go ahead and purchase the RHD kit, so you have an email, Rama.

The head is finished. There was some slight corrosion in one of the coolant passages, so that was welded prior to milling. The head got refreshed with new guides and all, and we went with the +1mm intake and exhaust - flow numbers will be posted soon. Really hoping the kit will get here in enough time to flow test them on the head as a unit - the car is supposed to be on the track mid-September, really would like to meet our deadline.

This could almost happen here on this car, but don't think we will have time before the deadline since we only have 45mm Jenvey stuff here and would be a while before we could get a set, but might just throw the 45's on your manifold to see what happens.

I already have all the flow data from this thread, which included stock manifold on a stock head...


Just need to stack the RHD stuff on the head, maybe even mix things up with Extrudabody, Rowland and perhaps even Jenvey. It all depends on how quickly Rama can get the kit overseas. For a short time we will have all three kits here at once.


Had a little help from my friends (**singing horribly out of tune**).


It's a track only car, they will be run open. The car only does 20min sessions.

Will let you know what they do with a 272, ported head, 272 cam and headers/exhaust.

They were tested previously on a bone stock m20 which made a baseline of 150whp, adding the ITB's made 174. 24whp increase on a tired m20 is significant, 16% increase from a bolt on...


To add, the tune would be useless.

We are tuning the stock Motronic. Currently working on another m20 with ITB's. We have the car running, and are just getting into the tuning stages on this one (pic from last week, it's all buttoned up now)...

We will soon have 3 different setups. I also have ITB's on my m50 powered e36 beater, also running stock Motronic...

Alpha-N, no load compensation. I use an emulator to tune on the fly and a chip burner to burn the final tune.

Because I'm using a 0-5v TPS in place of the AFM. In fact your tune by default was on my emulator from the dyno session earlier in the thread. Car starts and runs, but not good at all. Any touch of the throttle and the AFR's immediately jump to mid 20's. We played with th eTPS angle to match the voltage outputs of the AFM, but the ECU is expecting a LOT less air to be entering the system so early. It's going to take hours of tweaking to get it to run properly. Will post a video of it's current running condition on Extrudabody setup, but the car this thread is about will have similar traits.

Can't embed since it was just uploaded, but here's a demonstration of what's happening now with th eECU in stock configuration.

This is going to take a while. The 413 variants have an AE table that helped a lot with the throttles "gulping" air when a lot of throttle was applied.

m50 TPS wired in place of the AFM, angled to read the same voltage at 0 throttle as the AFM did at idle. Using Tunerpro's tracing, I verified the ECU is seeing basically what it would if the AFM were there. I think it's because the AFM door would open more gradual than the 5v signal is moving with the M50 TPS directly on the throttle shaft.

Basically I am doing the same here. The OEM TPS switch and the m50 variable TPS are both on there with the TPS (m50) going back to AFM input. To do this, he will have to rotate the TPS to match the AFM voltage. Still working out bugs.


After lots of playing around, found a happy medium for AFM input using the TPS. We still haven't done any actual tuning as we wanted the ECU to recognize idle and WOT and it now is. Idle is stable and as long as it goes directly to WOT, it will free rev (AFR's still need some work, but it's a start). Holding partial throttle, get's all wacky. This means we have our minimums and maximums worked out and can change some maps to get it to behave on the street.


Flowing the throttles today. Interesting enough, the m20 head is efficient enough to max the 40mm TB's in terms of flow, which is probably a good thing when taking velocity into consideration (a 40mm throttle with butterfly should flow 167-ish CFM). Here's some data. Bare head with a port entrance fixture attached, ITB's attached, then stock mani attached.

Here's a graph showing the flow difference. Kind looks like RHD's test mule dyno plot.

And pinned open.

You can see more about our flow testing methods here...


And because pics are fun.

It's because the ITB's are maxing flow. I haven't flowed one individually, but it's right where Dynomation says a 40mm throttle potentially flows. .500" is 12.7mm, doubt many people are running that kind of lift, specially on a stock head. Would have to cut a stock manifold to measure diameter, but remember, manifold runner would be also lacking a butterfly (throttle plate).

This is static flow testing resonance and reversion would be in a running engine.

To add, we should be looking at mid lift numbers as that's where the valve spends most of it's time, the valve sees mid lift twice per cycle.

272 IE cam, and +1 valves. with very little porting.

I stand corrected. The dynomation figures are in 1.5" Hg, not 28" h2o. Doing a conversion with math, that should equal almost 200cfm.

I wish it could have happened now. Wanted to get that (green) Extrudabody car together first to do the tuning sessions to have a base for this (white) car since they will both be running Motronic. More on a timeline budget for the white car than the green one. The green car is getting a plenum built and turbo in a few months, so it will be apart again and can test then. There is a spare set of Rowland here that could be messed with, but no extra TB's.

They both have 272 cams, the green car is an automatic transmission (cough, cough), but they will both hit the dyno.

As afr as the peak TB flow, I looked at dynomation's flow and saw what happened with the flattening of the curve on the chart. the numbers matched max in 1.5"Hg and instantly thought it was peak flow for the throttles at 28"H2o, but now it has me curious.

Did a lot of flow testing today, made it to the stock head with over sized valves (standard valve job to fit valves, no porting). Surprisingly the average flow dropped a lot, very little gain below mid lift, and a loss everywhere else.

Wonder how close they will be the the Jenvy stuff. Do you have pics or dimensions? Just would need one throttle/pair for real world testing. Now that we have benches in two states, we have been pondering the pass around plates to calibrate the benches to the network.


It's nice to have the equipment needed to test things.

Newest comparison of data.

You already saw the first three tests. .500 lift was removed to avoid confusion, and the fact that we will not see lift that high. Pay attention to the mid lift areas (under .300") as well as the average flow. Many people get confused and just want to see high numbers, but in fact it's more important WHERE the gains are. The valve sees mid lift twice per valve reciprocation, so peak numbers aren't as important as area under the curve (much like dyno numbers).

Test #1 is a stock bare head with test jig.

Test # 2 is a stock head with the stock intake and TB attached.

Test #3 is a stock head with the ITB's

Test #4 is a stock port, no induction (bare head with test jig) and a 1mm over sized valve. Take note of the mid-lift numbers.

Test #5 is a stock port, again no induction, custom valve job to suit the over sized valves.

Test #6 is same as test #5 with the ITB's added.

Test #7 is also the same as #5 and #6 with some port testing and doing some simple touching of the ports where needed. Almost NO material removed. Not even enough to make a pile.

I have a feeling by doing a little to the manifolds without removing much material, we could see a little more, even, but this is good enough in my opinion. The gains were moved into all the correct lifts. Boundary layer is a good friend of mine. Creating flow and velocity and not increasing port volume by much is a wonderful thing. Do what needs to be done, where it needs to be done can have great effects. "Hogging out" and removing large amounts of material isn't always best for any given situation.

Also, take note of the over sized valve flow. Sure one would think adding bigger valves is better (bigger is better, right?), but, the bench doesn't lie.

Now to finish the head up, get it on the car and let's see what the dyno says.

Unless you want to flow test heads, yes, leave them alone. Been saying that for years. Even if test #7 was explained, it's not the same as real world testing. Besides, let's see if the dyno backs up all these years/tests. These gains/tests are a joke to most, and would laugh at a goal of 200hp. My machinist always laughs at me since he has a 2000+hp drag car, but it is what it is. Just a small shop trying to get hp from a 25+yr old platform for not a lot of money.

It's coming. It really wasn't happy with the modifications as it sat, but it's driving around as of now.



Yeah, theoretical flow according to dynomation using rough math to convert from 1.5" Hg to CFM, a 40mm TB should flow over 200. And yes, you are absolutely correct. The most flow with the smallest CSA possible keeps the velocity up and makes for a good head. People tend to look at peak and high lift numbers (on head flow as well as dyno plots) and often miss the "area under the curve". This is why i like to include AVG flow numbers across the lift points.

On a side note, the Extrudabody throttles were quite out of balance. Your throttles share a shaft which should make them easier to balance since it's really three pairs where the EB kits are 6 individual throttle shafts with adjustments in between. After using a balancing, the EB kits became much easier to tune, and sound much better. Curious to see how well the RHD ITB's are in tune with each other.

If things keep going thew way they are, seems like we will be working together often. Would be great to have a hub on this side of the pond for support/sales, as well as the development of Motronic tuning for those that are looking for a plug and play setup.


The biggest problem is going to be what Digger ran into with booster clearance. Really, the trumpets should have one throttle diameter clearance in all directions, and as they are now, they lay right on top of the booster.


This. Thing. Sounds. Amazing.

Went with dual 2" exhaust, x pipe ~34" from collectors, twin 12" resonators.

10am appointment at dyno.

This one is staying Alpha-N Motronic 1.3.

Cam is broken in. Needs another oil change before dyno, but here is a free rev just for giggles.

More hooning.

Simple, effective and serviceable. The X-pipe that came with the headers are something to be desired.


Didn't get a good pull. Fouled the plugs during tuning, so we attempted to tune another customers' 944t, but his ECU installer botched the wiring. Wasted a few hours of dyno rental with no results on either car. Got another appt later today.


We were trying to sneak between appts on dyno, as the owner is a friend of mine, but they all ran over their slot on Friday, so we just used the time to iron out the M1.3 Alpha-N, and ended up giving up. Int the M1.3 code, Bosch used a transfer function map to save valuable space on he 256k chip and dies to the nature of the formula, airflow could not be transferred to a linear table. One might be able to get it to work, but it will never be street-able. Since there is an exponent in the formula, the final air flow calculation can never be linear (as the TPS is putting out that replaced the AFM).

Standalone will be at the shop tomorrow afternoon, and it will be tuned with a P&P MS from Whodwho (Keith).

We kept fouling plugs trying to get the M1.3 to behave, but it simply wasn't working. Just pulling the car from trailer to the dyno on the stock ECU with a free-rev tune fouled the plugs. Changed them, got it to pull a couple times, but could never get over 135whp, and after each run, there was a dead cylinder from a fouled plug - laser thermo on header primaries was always showing the dropped cyl at 120 degrees, the rest were in the upper 200's when the dyno brake stopped the wheels. We would change the plugs, then it would happen again and not always on the same cylinder, and at times it dropped 2 after a pull. I went out of town for the weekend for a planned family visit, just ran out of time.

If one had a LOT of time to change plugs and change the AFM transfer function multipliers in the Motronic, you MAY be able to get it to behave, but then it would still be finicky. When you tune the part or wide open throttle, the other suffers. Idle was never good, even putting the stock throttle switch on it to revert back to idle maps since the AFM tranfer is still calculated in.

I know this may as well be Chinese to some, but trust me, it's nearly impossible compared to the Motronic 3.x (413 and 506 ECU's) we were able to run in Alpha-N. If one was to start with an M50 Vanos harness and M3.x ECU on the M20 with ITB's, I feel it would be a better starting point.


Didn't hit 200, but it's healthy. Before and after.

With spacers. Wanted to try with them and hood closed, then without hood closed, but already over stayed the welcome on the dyno as it was. First few pulls, it was breaking up over 4500rpm, had to adjust the CPS closer to the wheel. Whodoo was kind enough to answer the phone and gave the tip. Figured it may be failing, but guess the MS is more sensitive than the stock ECU.

To add, judging by the graph, I feel a larger cam would have kept pulling and not drop the lower end power by much, or maybe adjust timing instead but we used a stock fixed gear on this build.

My JY m50b25 with 45mm ITB's vs the modified head/cammed m20 with 40mm ITBs...

I will take the single cam all day


Customer brought the car back to do a 2.8 stroker, almost a year to the day later.

The fresh 2.8 REALLY woke this thing up, gains everywhere. Went to the dyno today and top power was 211whp/198wtq with more left in it, but the injectors are at 126.6% duty using 19lb - 100% duty at 5500 as you can see in the AFR graph. For some reason I never even thought about the injectors (partly because I didn't think it would make this much). Goes to show you how much better sequential fire is, as I have been to 223whp with 17lb in an e36 with some room.

Brought the FauxPro and mount this time, so got video. Will post a link once it's edited.

Here's the graph so far...

Time for some bigger injectors and a another trip to the rollers.

Not sure why it looks like that on the screen shot, doesn't in the dyno software. Replaced it with one that's more clear.

Better screen shot that includes the pull before we started any work.

The graph below is a comparison of a modified s52 vs this m20. Now I really can't wait to go back! We only did a few pulls, so the m20 graph will be much smoother.

VAC stage 2 head
Sunbelt cams
generic long headers
m50 manifold
10.5:1 forged pistons
TRM tune


Probably could use an adjustable gear with the block and head being shaved, but it doesn't have one. Probably just going to keep it simple, put larger injectors in and call it a day.

It does. 100% duty at 5500 and you can see the graph go lean after.

Thinking about 36lb to give some room, 850c would be a bit overkill lol.

24's might do it, but want to leave some margin.

It did go over 14 a few instances. Looking through the logs now. Was wondering why we got a stutter a couple times at high RPM. We only did about 7 pulls and a couple of them weren't full. There's a couple places the duty was much higher and the AFR's spike as if the injector just stopped firing.

EDIT: Found one log to be at 146.2% DC lol


Put 24lb in tonight and preliminary tuned it, will dyno tune tomorrow.

Yeah. Just tough to get in high gears with a loud race car and industrial/public streets. If they are too small, will order, but the customer is getting antsy about having his car back. Did some rough calcs based on old vs new flow etc, should be in the 80's duty as you suggested. Time will tell though, eh?


Had some fun today at the dyno. Made a best peak hp @ 217, but that was with the runners shortened and mid range TQ suffered. Overall best "power under the curve" was a peak of 214hp/202tq.

Sorting the graphs, will post some up.

Ugh. First I grabbed the wrong folder from the dyno PC, so can't post any graphs right now, but that's not the worst part.

The vapor in the video turned out to be a developing problem. Got worse today, so opened up the valve cover when we got her back in the shop. Lots of milkshake on the back of it, but dip stick looks clean - threw the pressure tester on it and that stupid #6 cam journal cracked

Pretty consistent with here. Duty cycle is close to yours, too. These Ford 24lb injectors are the single pintle and shoot pretty sharp.


Head is off, new core is being prepped/ported/machined. Owner was a bit bummed, but happy it was noticed now, and not after the coolant wiped out his new engine.

Worst part is, the old head was pressure tested and ran for a year before it cracked. Never overheated, but was abused.


Replacement head has been machined and is on the bench. Between this and the other e30 being ready for the 14hr race in Atlanta, Murphy's Law is in full effect.


Availability and timing. Wanted to use the 36lb foggers but they didn't pass the flow tests, so went with the 24's we had on hand.


Just happen to see this finally. Not much to update

We found more flow from the 885 heads, and wanted to go with the new IE 284 cam to get a few more ponies, but the owner had his second child recently (at 46yrs old at that). So, he decided to put the car up for sale and buy a more manageable street/track car to avoid having to trailer this one to/from the track.

It was hitting top speed at Daytona, and having to feather it with the needle buried at 7000rpm with the 4.10 and 225/50-15 slicks. With a larger cam and 3.73, this thing would be even crazier. He went with GC coils, BBK, and stripped the car down to 2400lb sans driver.