Dart Flow Numbers

[Trmnatr]

I use Dart heads but usually dont have them flowed unless there is some porting going on.

I remember a huge flow number when Dart first released the 200cc, 215cc and 230cc platinum heads

I found some information i had saved on the 215 platinums from before they were available, How accurate is this flow number? Do they really flow this much and the magazine articles and Dart lowered the numbers by a great deal to be conservative ?? Here is what i have from .200"-.700" Intake/Exhaust

.200" 136/109
.300" 193/158
.400" 239/198
.500" 273/208
.600" 289/214
.700" 293/219

The main reason i ask is this: Some of Dart's competition advertises a flow number of say 270cfm and a few people did not get that flow number when they got their "New" heads so the maker replaced the heads with a new set that did deliver

I recall those flow numbers being accurate for the Dart 215 platinum style iron eagles, Is it that Dart is advertising a lower flow number so they dont send out a set of heads that flow 1cfm less than advertised and get stuck with an unhappy customer such as the other brand head that i have seen this take place twice?

[Dart Vader]

To be honest we almost never use flow numbers these days. Our newer heads are all developed on a wet-flow bench, which has completely different flow figures and referrence points than a typical flow bench.

Yes, we do still make airflow numbers available, I'm not sure if we used conservative ones, we do like any figures we release to be accurate and not over-inflated, but it's also entirely possible that those flow numbers are spot on. In wet flow testing we have found that heads with approximately the same (Or sometimes, even lower) airflow numbers can have significantly better performance based on fuel behavior in the fuel/air mixture. Because of that we have started focusing less on airflow and more on the more realistic testing conditions that wet-flow provides.

But in any event, if you do want some idea exactly how conservative our stated airflow numbers are let me know and I'll talk to one of the techs about it.

[Trmnatr]

To be honest we almost never use flow numbers these days. Our newer heads are all developed on a wet-flow bench, which has completely different flow figures and referrence points than a typical flow bench.

Yes, we do still make airflow numbers available, I'm not sure if we used conservative ones, we do like any figures we release to be accurate and not over-inflated, but it's also entirely possible that those flow numbers are spot on. In wet flow testing we have found that heads with approximately the same (Or sometimes, even lower) airflow numbers can have significantly better performance based on fuel behavior in the fuel/air mixture. Because of that we have started focusing less on airflow and more on the more realistic testing conditions that wet-flow provides.

But in any event, if you do want some idea exactly how conservative our stated airflow numbers are let me know and I'll talk to one of the techs about it.

Yes, check on that please. I recall those flow numbers {in post #1} being advertised @ 28" then after the old design Iron Eagle heads were gone they gave the new Dart platinum's a flow number of 268/174 @.600" @28" which was the same as the old - Is this to guarantee they will flow the advertised amount

To be honest, i remember this flow number in the chart in post # 1 plus i did some checking and its the same airflow number Jeg's advertises to compare Dart 215's to World 220's and RHS i think - Identical flow numbers at Jegs as i posted above which i had stored in our old computer system and i had to pull them out :D

I also remember the Dart 200cc platinums being rated at like 274 @ .500" lift @ 28" - Here is what i have for the 200cc from .200"-.600" intake/exhaust @28"

.200" 130/109
.300" 194/158
.400" 242/198
.500" 274/208
.600" 283/214

Here is what i have for the 230cc platinum heads too from .200"-.700" intake/exhaust @28"

.200" 138/109
.300" 201/158
.400" 247/198
.500" 280/208
.600" 297/214
.700" 306/219

And of course the 215cc runner info i have is on post #1

[Dart Vader]

Yeah, the new platinum heads do have mostly the same flow numbers as the old versions of the heads, a couple airflowed a little more. The iron eagles didn't change airflow-wise (not significantly anyway).

The wet-flow numbers (and power output) are considerably better, however.

[Trmnatr]

Yeah, the new platinum heads do have mostly the same flow numbers as the old versions of the heads, a couple airflowed a little more. The iron eagles didn't change airflow-wise (not significantly anyway).

The wet-flow numbers (and power output) are considerably better, however.

Yes, i know this. I have a customers combo i built with 200cc heads and it ran much much quicker than previous combo's did with the same parts - Only differenxe was the old 200cc heads and this engine had the 200cc platinum's

So those flow numbers @28" i have are wrong?

[Dart Vader]

Flow numbers normally show a variance of 2% or so from one set of tests to another.

The flow numbers you have listed here are correct according to our techs.

[Trmnatr]

Flow numbers normally show a variance of 2% or so from one set of tests to another.

The flow numbers you have listed here are correct according to our techs.

Well, thats good to know that im not going crazy !!!!

I have a set of 200cc platinum heads here for a customers engine, If possible and he will let me i will send them up to the local head porter and have a cylinder flowed and let you guys know what it does via e mail

I like the fact that the rated number Dart gives is less than they actually flow - If Dart handed out that the 200cc flows 274 @.500" every customer that only got 274+ would be happy, now they are getting airflow beyond what they thought

QUESTION: Does the Dart 49cc Iron Eagle Platinum flow any less with the combustion chamber design of the 49cc chambers ??

[malihoochie]

The 1st press releases for the Platinum heads did have flow #'s advertised higher than the flow #'s we currently give out. The 1st #'s were from our developed pieces and our 1st production parts. The current flow #'s are an average from heads pulled ranomly fron the shelf. In 2005 a independent small shop flowed a bunch of heads including our out of the box 200 Iron Eagle Platinums. The flow # they came up with matched our intial #'s within 3 cfm up to .600" lift, at .700" our # was a bit higher than theirs.

Advertised flow #'s are a spooky thing though and more people need to realize that they are a small part of the puzzle and not the end all of the "what head is better" question.

[lun40119]

Flow numbers normally show a variance of 2% or so from one set of tests to another.

The flow numbers you have listed here are correct according to our techs.

Are those the numbers out of the box, as cast??????????

Jake

[Dart Vader]

Are those the numbers out of the box, as cast??????????

Jake

Yes indeed.

[lun40119]

I had always assumed lower, cool thanks.

Jake

[stevemc1979]

Yes, check on that please. I recall those flow numbers {in post #1} being advertised @ 28" then after the old design Iron Eagle heads were gone they gave the new Dart platinum's a flow number of 268/174 @.600" @28" which was the same as the old - Is this to guarantee they will flow the advertised amount

To be honest, i remember this flow number in the chart in post # 1 plus i did some checking and its the same airflow number Jeg's advertises to compare Dart 215's to World 220's and RHS i think - Identical flow numbers at Jegs as i posted above which i had stored in our old computer system and i had to pull them out :D

I also remember the Dart 200cc platinums being rated at like 274 @ .500" lift @ 28" - Here is what i have for the 200cc from .200"-.600" intake/exhaust @28"

.200" 130/109
.300" 194/158
.400" 242/198
.500" 274/208
.600" 283/214

Here is what i have for the 230cc platinum heads too from .200"-.700" intake/exhaust @28"

.200" 138/109
.300" 201/158
.400" 247/198
.500" 280/208
.600" 297/214
.700" 306/219

And of course the 215cc runner info i have is on post #1

I wish I could have gotten these numbers out of my Platinum 230's. @ .700 mine flowed 289cfm out of the box. I had mine CNC'd by M2 to get some decent flow numbers out of them. they are now flowing 320 @ .700 and 333 @ .800. Had I knonw it was going to cast me so much to get decent numbers I wold have just bought the AFR's. Now I'm stuck with these heads because I have so much invested. Thanks.

P.S. I also had to get custom offset shaft mount rockers to use with these heads. +.300" intake and -.100" exhaust. The 1.6:1 stud mount rockers would roll off the valve tips before full lift.

Perhaps I got the worst batch of heads ever made? I dunno.

[blown71nova]

I wish I could have gotten these numbers out of my Platinum 230's. @ .700 mine flowed 289cfm out of the box. I had mine CNC'd by M2 to get some decent flow numbers out of them. they are now flowing 320 @ .700 and 333 @ .800. Had I knonw it was going to cast me so much to get decent numbers I wold have just bought the AFR's. Now I'm stuck with these heads because I have so much invested. Thanks.

P.S. I also had to get custom offset shaft mount rockers to use with these heads. +.300" intake and -.100" exhaust. The 1.6:1 stud mount rockers would roll off the valve tips before full lift.

Perhaps I got the worst batch of heads ever made? I dunno.

ALL good info.

[Trmnatr]

I wish I could have gotten these numbers out of my Platinum 230's. @ .700 mine flowed 289cfm out of the box. I had mine CNC'd by M2 to get some decent flow numbers out of them. they are now flowing 320 @ .700 and 333 @ .800. Had I knonw it was going to cast me so much to get decent numbers I wold have just bought the AFR's. Now I'm stuck with these heads because I have so much invested. Thanks.

P.S. I also had to get custom offset shaft mount rockers to use with these heads. +.300" intake and -.100" exhaust. The 1.6:1 stud mount rockers would roll off the valve tips before full lift.

Perhaps I got the worst batch of heads ever made? I dunno.

From flow bench to flow bench you can get a 15cfm difference, 289cfm (yours flow) + 15cfm = 304cfm {they were rated @ 306cfm}

Take that in to the big picture also

[Trmnatr]

I wish I could have gotten these numbers out of my Platinum 230's. @ .700 mine flowed 289cfm out of the box. I had mine CNC'd by M2 to get some decent flow numbers out of them. they are now flowing 320 @ .700 and 333 @ .800. Had I knonw it was going to cast me so much to get decent numbers I wold have just bought the AFR's. Now I'm stuck with these heads because I have so much invested. Thanks.

P.S. I also had to get custom offset shaft mount rockers to use with these heads. +.300" intake and -.100" exhaust. The 1.6:1 stud mount rockers would roll off the valve tips before full lift.

Perhaps I got the worst batch of heads ever made? I dunno.

The only reason the rockers rolled off the valve tip before max lift is your pushrod is too darn long or short depending on which way they rolled off

Pushrods too long and your wear pattern will be towards the exhaust side of the head (on the valve stem)

Pushrods too short and your wear pattern will be towards the intake side of the head (on the valve stem)

Use alot of these heads and always use Crane Gold rockers, Never 1 issue.

[stevemc1979]

Even the first set of Jesel shaft mounts wouldn't work right. They were +.200 and straight up. My net lift with 1.6 rockers is .712". Custom made pushrods were used with all three sets of rockers. And, my engine was built by a professional builder. My engine is relatively tame compared to what he usually builds. He's been racing since the 40's and has built everything from inline 6's to top fuel engines (Larry Minor Racing team).

And just a side kicker, he uses gas porting in the pistons on ALL of his high power engines.

[Trmnatr]

Even the first set of Jesel shaft mounts wouldn't work right. They were +.200 and straight up. My net lift with 1.6 rockers is .712". Custom made pushrods were used with all three sets of rockers. And, my engine was built by a professional builder. My engine is relatively tame compared to what he usually builds. He's been racing since the 40's and has built everything from inline 6's to top fuel engines (Larry Minor Racing team).

And just a side kicker, he uses gas porting in the pistons on ALL of his high power engines.

And? Thats been around since the 70's. Bill Coleman was doing lateral gas ports for local racers here in the early 70's

With shaft mounts you dont use the pushrod to adjust it, You use a longer/shorter pushrod with stud mount rockers.

With a shaft mount you install a valve and mark the valve so you know when your at MAX lift. With the rockers bolted to the stand if the wear pattern is to the exhaust side of the head you need a longer valve and/or mill the stud boss down

If the wear pattern is towards the intake side of the head you need a shorter valve and/or shim the shaft mount stand up

I dont care if you have been doing it 50 years, Its easy to make a mistake

[MOD]

(quote)QUESTION: Does the Dart 49cc Iron Eagle Platinum flow any less with the combustion chamber design of the 49cc chambers ??(quote)

I am curious about this as well.

[want-a-be]

Ron's porting in St. Louis, Mo. has a great cnc program for these heads. We just talked today about them. Think they flowed around 315 cfm at .700" lift.


This is his web site.

http://www.ronsportingservice.com/index.html

His Phone number is 636-447-4042


Don